CORRECTIONS, thanks to the folks who commented below: 0:08 - Unbonding is removing the ground strap that connects ground and neutral, not ground to frame. 3:25 - The generator is a single phase, so it couldn’t run “out of phase.” Instead of 120v going to each leg, most or all of the 240v was going to one leg, and almost none to the other.
I just removed the ground wire from the plug terminal that goes into my generator and left my generator bonded. That way I can still use it around my property remotely and have the bonded ground.
Each leg always has 120v to neutral. The 240v is across the two legs without a neutral. With a missing neutral, 240v is present across the loads of the two legs in series. Since the loads will not be equal, the voltage drop across devices on each leg is different and some devices will see too high of a voltage and may burn up as happened with your surge suppressors.
@bluesrider. The 240v cable between my generator and box plugs into the generator carrying the 2 hits, ground and neutral. When the wires from the female receptacle on the generator go down to where you unbounded your Westinghouse they connect to their respective tabs, which are then bonded. What’s the difference between removing that jumper bond wire on the generator and having your transfer switch only connect the neutral, 3 wire config, and me removing the copper ground wire in the cable from the male ground pin on the plug? I don’t have a transfer switch I’m wired into a 50 a breaker in the main panel and manually switch off the grid after the Power goes out.
(Unbonded) For 20 years I’d been connecting my bonded generator to my main panel with no problems. After seeing a James Condon video on this topic I unhooked the cable ground at the plug. Had a power outage and no problem, but I don’t want any problems. I just don’t see the difference between what I did with the cable and unbonding inside the genny. I have an 8’ ground rod right below the main box I plug the gen into.
@@jtjones4081 That was very foolish . Now you have no ground to the generator. If there is a ground fault the circuit breaker on the generator won't see it and it will burn until the wires burn through. Not to mention various code violations.
A 120/240 generator cannot go out of phase as it only has one phase. What probably happened is loosing the neutral caused the power being consumed to find an alternate route back to the generator. Meaning that instead of 120 -N - 120. you had for example 50-N-190. Those surge protectors operate by clipping any over voltages. depending on the specific component (a metal oxide Varistor is usually used and rated around 140-150v) will cause the Protector to try to protect. IN this case the Surge it was seeing wasnt due to power issues as a fault in the wiring of the cable. Glad you found what caused it.
Over revving will also clip them MOV's, Diodes, trans, IC and wipe out most battery chargers, computers, digital equipment etc. 130v at 65 hz starts driving shit crazy and turns the Genie into smoke
Your partially correct, You will read different voltages at the loads but keep in mind that the generator still only does 120vpk 240v p/p If you have equal loads say two identical fridges can you run them in series no neutral? Or say have 120v compressor in series with a deep freezer in the garage? Will one run and not the other? Ahhh the age old question? Yes or no, in or out, up or down, right left, 1/0, will one burn up and not the other? Keep in mind what is in series and what is in parallel, isn't electricity fun.
@@bluesriderDFhe's on the right track but his explanation is erroneous. The lost generator neutral caused a backfeed through all the branch circuit neutrals putting 240v on your 120v equipment.
@@ianbelletti6241 No. he is spot-on. It does not put 240V on your 120V legs, it depends on the impedances of the connected loads at any given time. It can vary between 0V and 240V on a leg (and the converse on the opposite leg). I did not see any errors or typos in what he stated.
Definitely a classic example of a floating neutral. A couple years back went on a service call in a late 1970s home, where the TV, DVR, DVD player and stereo system in living room smoked up so bad it set off the smoke detectors in the hallway and master bedroom after a 1500 watt electric fireplace had been running for over an hour, plugged into a different outlet on the other end of the living room. Come to find out, all the receptacles were backstab connection and part of a multiwire circuit (L1 & L2, sharing a common neutral) and the neutral burned up on a receptacle upstream, making everything downstream into a series 240V circuit and depending on the load balancing, voltages applied accross the load can range from nearly 0, to nearly 240. Also pointed out to the homeowner and corrected, the two single pole breakers controlling the multiwire branch circuit, by installing an identified handle tie to ensure that if either leg trips the entire circuit is dead, protecting anyone working on it thinking its dead when in fact one leg is still hot, evidently this wasn't required when the home was built. This whole catastrophe could have been avoided, had article 300.13 (B) of the NEC been applied which states that for multwire branch circuits, the continuity of the grounded (neutral) conductor shall not depend on connections to receptacles, lamp holders and so forth, where the removal of such devices would interrupt continuity. What this means, is that the neutral on those receptacles should have been connected via a pigtail
That unfortunately isn't as true as you would normally hope. With the increased use of better protective earth connects you can easily get a competition between the supply company's attempts at providing a low impedance neutral (truly reference to earth at the generators, subs, and transformers) and the parallel earthing impedances for the multipoint safety protections. It gets worse in three phase supplied zones where the individual phase takes are unbalanced and the protective earth-neutral bonding enhances the diverted neutral current. It will depend on your generic location as to whether the local buildings and construction styles will make it more or less likely , and not forgetting 'fault' conditions.
This was one of my arguments for not unbonding my generator, having more or less a redundant neutral. In the end I did unbond it and have not had any issues, but this video shows the importance of having a good solid connection all the way around.
Why did you unbind it if you were for bonding? This topic is so confusing, nobody has a definitive answer. I haven't had an issue running my generator bonded.
The surge protector did catch on fire because it had a very /low/ resistance. Not high resistance. The MOVs inside go low resistance when exposed to over voltage, and they are supposed to short out and blow your fuses. It can be dangerous supplying power from a generator as it might no be able to make enough short-circuit current to trip thr fuses.
The following is an experience I had a friend asked me to look at. What I found out I had never heard of. When turning on several lights in the house, the house lighting would slow flicker or surge up and down, get brighter then dim. Everything checked out to be normal throughout the house, so I assumed it was a lost neutral somewhere in the house. I have years of experience in residential, commercial, and industrial electrical field's but I'm not a licensed or insured electrician and screwing with a lost neutral can burn down your house, so I recommended having a licensed and insured electrician take a look. They did. The electrician found everything was normal throughout the house also. Eventually he found the problem. It was a mixture of different brands of LED light bulbs throughout the house causing the fluctuation. My friend changed all the LED light bulbs to one brand and that fixed the problem.
Before you unbonded your ground at the generator, your neutral current was flowing through the ground conductor in the extension cord and the bonding jumper. So it was a related problem and unbondining your generator is correct. A ground rod would NOT have mitigated this problem even if you had connected it directly to your service entrance rod. That would have made the neutral current flow through your ground rod wires.
@@bluesriderDF That's rough. A continuity test is usually enough. My first thought after all the troubleshooting was "why didn't you test the cable first since it's the easiest? "And then I realized I would have followed the same process as..."it's just a cable and how could THAT be the issue?"
there are a lot of lessons in this video. This could be a whole lesson for an apprentice or journeyman refresher course. Open neutrals are something we run into a lot and are often times at the service point. Interesting video and I am glad that you are safe!
That generator bond covered up the cable's unconnected neutral. By removing the bond, there was no more neutral. All unbalanced circuit loads would get up to 220v pumped through it . Only balanced loads will get 110v.
Side note: 250.30 of the NEC requires separate bonding wire to the service panel when connecting a generator in this situation if the neutral remains connected to the grid. However, if the transfer switch also separates the neutral from the grid, then the generator needs to be internally bonded.
Interesting. Thanks for sharing. Lost neutrals and meltdowns are not something I normally associate with generator usage. I made up my own generator extension cords. After watching, I'll open them up to absolutely sure connections are still snug after 2 years...especially the neutral.
I swear I said to myself about 10 seconds after you suggested an immediate fire, "His cord has a faulty neutral, and the ground wire previously provided neutral because they were bonded at the generator." I'm glad you and your house are still standing to talk about it.
When the neutral get loose like that one leg goes high, the other one goes almost to zero volts like you said on the video and everything is connected in series between the two phases. The culprit is the loose neutral connection. It can also happen on the utility side of the installation.
Thanks for sharing your experience. Great information. I am wondering if the constant vibrations of the generator ended up working the screws loose over the 20 years.
Thanks for sharing on your experience with this!!!! I'm an electrician, have installed many different types of home generator connections and transfer switches, panels , etc. But that Generator "Cord Set" some call it could be a failure that me as an electrician may not catch in my Testing, after an installation. If the home owner replaces a cord, and gets a bad/defective cord set, the result could be very bad. So important to validate/inspect/test the cord set as well. God bless
If you haven’t already done so, I’d recommend a whole house surge protector. Although if it’s installed at the main panel and you are running over the transfer switch circuits only that would probably be bypassed. One thing I’ve done at my house is install a voltmeter at where the generator goes into the transfer switch. That way I could see abnormal high voltage if my neutral was loose.
I use a generator interlock on our service entrance. Like you I added a generator status panel next to it that shows current and voltage on each leg, and frequency. The generator is electric start so the status panel includes a DC voltmeter to monitor battery voltage and verify the battery maintainer is working properly. I also recommend installing a whole house surge protector in addition to point of use ones and also at hard wired devices.
The same exact condition that you experienced occurs all too often when utility feeds coming into a building looses the neutral connection, usually at the pole due to windy conditions or sometimes in the meter pan due to corrosion. The voltages go out of balance and cause all kinds of grief. The first clue is when some lights are dimming while others are too bright and subsequently burn out. There isn’t much that can go wrong that is worse than this.
I'm a roadie, and I never connect my equipment to a building's power or to a generator without first metering voltages and checking continuity (or expected lack of continuity) between ground and neutral. I've been asked by venue guys a few times why, and this video in part shows why.
You probably have had the neutral on that cord not functioning for the entire time and when your generator was in bonded mode the return path to the generator was provided by the ground wire on the extension cord. When you unbonded your generator you removed the ability of the ground wire to act as the neutral return. So not coincidental that unbonding the generator eliminated the neutral path and caused the issue.
I suspect this is what happened to me. A few years ago we needed the generator, I plugged it in just like I always do and the Keurig coffee maker took a hit. Seems like we lost other electrical appliances also. Inspection of the extension cord showed a loose wire. I don't remember which one it was. But I suspect it was the neutral. I tightened all wires in both ends of the cord and everything began to work correctly. Thanks for posting this, it helps me understand what I experienced.
Thank you, thank you, thank you. I have been stressing about the floating neutral question for about a month now and I am almost finished with the complete installation of my system. You answered my questions and really gave me down to earth answers. I'm good now. Thanks man.
I know the video is from Jan 25 and you may not get notified about this comment but I will leave it for others to see. When you do not have a neutral back to the power source in this case, the two hot legs will try making a circuit through the neutral how ever they can. In this case the MOV's in the surge suppressors were allowing the current to flow between the two hots and try to balance the load. The problem was that the MOV's in both power strips did not like the current flow through them and burned out. There is a reason a good electrician will setup a generator system to have the important systems on generator power and others like TV's and non essentials will be left out. In this case the only things that should be on a generator for a power outage is refrigerators, freezers, furnaces and well systems. Options would be lighting after that, but it should be in necessary areas like kitchens and maybe garages with the door opener. If you want to power the whole house, then I would suggest getting a whole home generator setup and if you want to go cheaper on the setup, then get a load shedding system. The only reason you should break the neutral ground bond in a generator is if the neutral at the transfer switch is using the neutral and ground connections in the main panel or at the main disconnect on the premises per NEC code 250.34(A)
I read all these comments, thanks for writing that up! It was educational, and i'm sure will help others. As you said at the end, I am using the neutral in my panel, which is why my generator is floating. A whole house generator would be nice, but don't have the funds for that and honestly, we don't really get that many power failures. Watch, now I'll get another week-long one. 😮
In the case of using an interlock kit (essentially a manual transfer switch?), does the code and/or mfg call for breaking the generator neutral/ground? Also, when and why are you required to drive a ground rod for a portable generator ?
@TheRobWay1 There is only one call for a ground rod on the generator, and that is when the generator is isolated from a main distribution panel that has no grounding. If the generator is attached to a main distribution panel that has grounding, then the cable that connects the power from generator to panel must have all wire connecting lines, neutrals, and grounding. If not connected, then you are violating NEC code for safe electrical conditions.
Be advised with your surge protector the MOV will blow and protect on the first fault, but instead of just not passing current ( open circuit) then the surge protector goes into bypass and you have no protection which as far as I am concerned is a huge safety issue
I'm an electrician retired after over 40 years in the craft. The reason that the voltage went too high on those Surge Protectors is that without an intact neutral the voltage will fluctuate with the amount of loading on each of the generator's energized conductors. The most heavily loaded side will have the reduced voltage and the lightly loaded energized conductor will have the higher voltage. The greater the difference in the loading the greater the difference in the voltage. In your case the load must have been markedly different on the 2 energized conductors and that produced a destructively higher voltage across the lighter loads which must have included those surge protectors. Why that happened is that in most cord sets of under size 2 American Wire Gauge (AWG) all of the conductors are the same size including the Equipment Grounding Conductor (EGC). Since the Neutral Conductor of the cord had an open connection at one end it was not carrying any current. The EGC (Grounding Conductor) of the cord had been carrying the imbalance current from the Grounded (neutral) busbar of the panel to the frame of the generator. The Main Bonding Jumper of the generator windings had been carrying the unbalanced current of the different loads the rest of the way from the generators frame back to the center point of the generator's windings. Under those circumstances both energized conductors carried their portion of the load current while the Equipment Grounding Conductor (EGC) carried the difference between the current flows on each of the energized conductors. Theoretically that is the wrong pathway for that current to return to the center point of the generator's windings but nobody consulted the electrons about our theory and they don't give a tinker's dam about what we think that they should be doing. Electric current does not take the path of least [resistance + reactance =] impedance. Impedance is the sum of the resistance and reactance to the flow of AC current. AC electric current takes all of the pathways available in inverse proportion to their respective impedances. Once you unbonded the generator winding's electrical mid point from the frame of the generator the difference in the current flowing on the 2 energized conductors had no way back to the source. That shifts the electrical midpoint of the generators voltage away from the heavier loaded portion of the generator's windings and toward the lighter loaded end of the generator's windings. There are devices that are usually used to protect recreational vehicles (RVs) from failures of the RV park's electrical system. One of the things that they do is disconnect the cord from the power source if the neutral conductor develops a high impedance or goes open. Using one of those plugged into the 120/240 volt plug of the Generator will disconnect the cord from the generator if either of those conditions were to develop. Tom Horne
I have a question for you Tom. Would you advise against removing the bonding jumper of the generator when tied in to a residential panel that’s bonded itself ?
@joshe9518 If your panel is bonded, that's why you should remove it from the generator, so you don't have more than one N-G bond in your system, per NEC code.
I am not an electrician, but have been doing home renovations for 30 years. I installed a 120 volt Coleman RV heat pump in my kitchen ceiling. I also installed a dedicated duplex outlet for this purpose. However, when I turned on the heat pump the first time, it ran but was noisy. So I shut it off and went to inspect the heat pump itself. The motor case was extremely hot. I troubleshooted the possibilities, and found I had connected the neutral to the neighboring breaker, so the circuit was 240 volt. OOOPS.. Five years later, by some magic, the heat pump is still working. Oversight happens to everyone, so your extension cord failure is not a surprise, but glad you figured it out. (PS: during the course of home renovations, I found many many electrical and plumbing faults, done by the "PROFESSIONALS".)
So this happened to my house.. the neutral fell off the transformer. This transformer fed my home and my neighbors, we both had our AC on. My house was the first in line, and the first breaker down from the service connection went to the living room. Let’s just say it found a ground, arched through the outlet and caught the wall on fire. Been out of my home for almost 6 months as they do repairs and replace/paint everything
Thank you very much, we need more people to learn how to figure things out. Everybody in they're life will need to have this type of reasoning in order to survive, can't just leave it up to somebody else all the time Thanks again for teaching people.
Very common issue on RV's that have 50a service connection. Im RV service tech electrical specialist. Old cords or old power pedistals at RV parks. For various reasons if the neutral line fails plug, cord, etc and a low resistance appliance like the hot water heater kicks on electric causes a huge imbalance on the two lines of 120 and typically fries a bunch of stuff in seconds.
I believe that the connections were tight from the factory, but got loose over the 20 years the cable was in service. Screws get loose over time from vibrations, so I believe that all the rough handling that the cable endured (specifically the plugs) from being dropped and dragged around made the screws loosen over time. It's a good reminder (even for myself as I haven't thought about this until now) to check all the cables that have plugs mechanically connected to them (with screws, not soldered on and potted in rubber fom the factory).
So basically the lesson here is that it takes maybe 15 seconds with a meter to check the continuity of your cord. And probably 99% of us have never done that. We all just assumed that if we didn't make it up ourselves, that it came from the factory correctly wired. That is a dangerous assumption, more dangerous than most of us realized. Thanks buddy, I am going to go get my meter out right now.
What I have just dealt with is a dropped neutral. As pointed out already, the current tried to find another route. If it's balanced between the two hots, it could operate without too much issue. However, if it goes out of balance (and that could be the difference of one lightbulb being on or off) it changes voltage on each line,(As already pointed out). Potentially feeding 220v to your appliances and lighting. It looks like Those surge protectors detected the higher voltage, saving your tv. Bulbs can explode and tvs can start arcing, but luckily you avoided that.
I had a series arc fault that started a fire in my basement. The load was a 120V 10A steam humidifier fed from a 15A outlet through a 25ft 14ga extension cord. It ran this way for many years. The cause was a poor connection at the female end of the extension cord. The arc persisted for a long duration and it burned itself open without tripping the standard 15A breaker. It started the wall on fire. Fortunately I was able to extinguish the fire before it got out of control. The solution: I ran a new dedicated 15A AFCI circuit to a GFCI outlet mounted clear of any flammables to feed only the humidifier. Running continuous unattended high current loads through manufactured cables or extension cords is hazardous because the connections in such cheaply manufactured cables cannot be inspected and verified. Arc fault circuit protection is my new best friend. 😊 And all extension cords get side eye from me now. 😒
Oh man! Glad you caught that. I had this house built and I'm familiar with it. When you buy somebody else's place, you have no idea what they did. One thing I wish they did here was use 12ga / 20amp for more circuits, especially in the garage. That might actually be required now.
Thanks for taking the time to make and post this video. I had this happen to a friend of mine as well. It blew out a GFCI wall socket in the master bath, and in the master bedroom, a TV and a clock radio. Oddly, everything was isolated to his bedroom and master bath, though the open neutral was on the generator-to-transfer switch cord.
Nice job finding the problem. In my home the surge protectors are in steel boxes next to the fuse box. Yes I still have fuses on the old part of the house. I never, ever use any plastic electrical devices like a UPS, surge protector etc. I had a problem with power and it was due to a corroded aluminum wire feeding my panel. When we had a hurricane and lost power I replaced all those wires. Been good ever since.
The best whole house surge protector is the Ditek brand they have a different MOV called a thermal protected MOV. What happens during a surge most surge protectors MOV's sacrifice themselves. Which is what you want, but the problem is if you get a 2nd surge now you have no protection. Ditek because thermal protected MOV can continue to protect they don't self sacrifice. It installs easily into your main panel.
Thankyou for the reminder to check your generator cords because you can get a defective cord and things do wear out as well as the fact that terminal screws can sometimes loosen.
Without a neutral and an unbalanced panel the leg with the biggest load will be the return for the light loads on the other leg. The less loaded leg will get the high voltage and the more loaded leg will get low voltage. The neutral takes the difference in voltage balancing the circuit. So that surge protector probably saw about 190 volts
Watch out, now all hardware on your electrical system which contains MOVs may have had their lifespan shortened. 2:31 These surge protectors are armed with metal oxide varistors which are simply components in parallel with the mains which will drop in resistance when exposed to transient spikes literally designed to short circuit and “neutralise” “clip” the spikes but with no ground on the generator it’s clear the open neutral put significant disruption in the MOV causing it to clip and short the mains.
@@bluesriderDF They're also referring to your appliances themselves, because their power supplies often have MOVs and suppression capacitors rates for a specific voltage for filtering as well. So, computers, TVs, washing machines, microwaves, etc, ALL have probably had their power supply lifespan shortened. If you have things breaking left and right a year or two down the line.... it was probably that power spike that caused it. If you were lucky though, the powerstrips that burned took nearly all the load and gave their lives to clamp the voltage down. Those components are designed to short as long as there's still a voltage spike. Chances are you'd be replacing a lot more devices if you didn't have them plugged in, so thank APC for making fairly durable equipment. I always recommend their stuff.
@@bluesriderDF Yeah, hopefully things took the path of most luck and least resistance. Good thing you found that though, that cable would have raised hell down the line regardless. Perhaps schedule a routine cable inspection, generators vibrate, and it probably loosened itself, now that I've had a day to think on what I saw in the video. Hey, you got it straightened out, and your system should be reliable again. Best of luck, stay safe, and have a great day.
Thank you for posting this video, in all honesty I have never even given the cord a second thought , but I will from this point forward. thank you again..
+1 on this comment. I’m a licensed electrician, and I f-ing guarantee you that better than 50% of electricians wouldn’t think of the cord. I am in a lot of electrician discussion groups and electricians will be the first to tell you that they are abusive, know it alls. I, on the other hand appreciate any opportunity to learn and grow, and that starts with humility. This is a very valuable, educational video and could potentially save lives.
I am glad you're okay and that it wasn't a lot worse as, from what you said in the video it could have easily have been so much worse. This could have all been avoided it there wasn't that stupid split-phase system as there would be only one possible voltage and loss of neutral would have meant a loss of power rather than massive overvoltage and fire. If there was only 220V, which could be done, things would be a lot simpler.
This was helpful, my new generator (that hasn’t even been fired up yet) is sitting outside waiting for everything else I’m needing to use it to arrive and you’re reminding me to test every aspect of it, the heavy duty cable that came today, etc before I trust any of it… Thank you
I have experienced loose connections at the generator end plug that I suspect is a result of vibration from the generator. These connections need to be checked regularly.
Your split phase imbalanced load could not get back to center tap on genset windings and found a path via N-G surge MOV’s. Typically surge protectors have a thermal fuse that should had taken it out of the circuit. That being said. It could had came back through you if you were a lower impedance path. Would recommend reinstalling that genset bond strap and keep a better eye on your connections and balance. Also check your connections to earth.
This information is invaluable. I’m currently in the process of having a transfer switch installed and have the same generator you used in the original tutorial. Thank you for sharing this.
Do not count your bus bars as phases. They are not phases only bus bar A and bus bar B same phase. Very good content in your post. Thanks for sharing. Rest assured most of us do not think of checking the UL listed store bought extensions. Now I will.
So, yes, that service cord was definitely the start of the issues. But the fire department was also right about the surge protectors doing their job, or at least attempting to. As you mentioned in the video and in more detail in your corrections note, you had high voltage on one leg and low voltage on the other due to the disconnect of the neutral. Search protectors like what you showed work by clamping the voltage to not exceed a certain set voltage, probably around 210 volts for your particular application. When a lightning strike or motor surge causes access voltage In the buildings, electrical system. A component in the surge protector called a MOV or metal oxide varistor clamps the voltage and prevents it from getting to your appliances. It does this by shorting current between Hot and Neutral temporarily until the surge dissipates. Normally, this short is only for a few milliseconds at most, But in your case, it was sustained because it was being produced by the generator. This resulted in the MOV(s) overheating. The first search protector you showed was too burnt to tell just where it started.. But the second one you showed, I could clearly see the MOV s on the circuit board, and yes, plural, there were several to increase capacity, and on the plastic shell, you could clearly see the melting starting directly below where the MOVs would be when the device is assembled.
You may have overcomplicated your thoughts enough to lead you down the rose colored road. A floating neutral is actually very simple. You have created two 120V busses that of course have 240 between them. Since the neutral is floating, now the 120V loads on each buss are in SERIES with each other, and depending on the loads on each buss, the voltage to the loads on each buss either rise or fall, depending on the amperage they draw. IE if you have two 100W lamps, one on each buss, in theory, they will operate "fine" But if you have say, a 60W and a 100W, the 100W will draw more current, and case more voltage to appear across the 60W lamp. NOW ON THAT fact, you could easily notice this if you installed a pair of voltmeters across each phase. If the loads are badly unbalanced, or if the neutral develops a problem, the voltages will become more and more unequal. I'm not sure that bonding / unbonding is a good strategy for safety here. THE GROUND AKA green circuits are NEVER intended for carrying current. They are FOR SAFETY in the event of shorts/ faults etc. And, this problem really is not unique to a genset, either. Something like an RV cable could have suffered the same problem with a bad cord/ cap connection.
Don't forget that there are now a lot of RFI/EMC filters in all the consumer goods and they all leak current (typ 1.6mA) from the live to wiring earth (not neutral), so you can build up a leakage bias that makes makes the system take up an unexpected potential difference between the systems. They are never truly 'floating'. The surge protectors are also reference to wiring earth. The ground circuits should be sized to ensure that they are capable of carrying fault currents large enough to trip fuses (old & new). It all gets very confusing because "Earth" can mean many different things and the assumption of ideal wiring (zero ohms, infinite capacity) on circuit diagrams can give a false indication of reality (and local 'practicalities';-).
So bottom line is unbond the generator when connecting to your house panel as the manufacturer recommends, but make sure you have a good cable....correct?
Make sure you have good connections all the way through from generator to your main panel. Anywhere there's a connection, there's the potential it could be loose.
If you use a single leg (120V only) generator and neutral or live gets loose you will lose all power, maybe the plug or whatever other loose connection starts arcing and catches fire too. With a two leg 240V generator if the neutral gets loose the 240V will be distributed among the different connected devices according to their power consumption, causing those with higher consumption to receive a too low voltage and those with low consumption to receive a voltage that is too high. But the neutral can also arc inside the plug or wherever it's loose and cause a fire.
I never do portable generators as separately derived services (SDS). I use a 2 pole disconnect and ensure the neutral and ground are bonded at the generator. I'm not saying you can't use a 3 pole and switch the neutral, it just adds unnecessary complexity without any return.
I thought that a separately derived system DID bond the neutral (such as a transformer)? If the ground is bonded to neutral at the generator, is current going back on the ground and neutral?
5:57 If I am not mistaken, your transfer switch is the first “panel” that the electricity flows through, whether running on power from the electric company or from the generator. When that is the case, your “main” breaker panel is a subpanel, and it must be wired as a subpanel is supposed to be wired by code. The big thing that must be done in a subpanel is ALL ground wires and ALL neutral wires have to be isolated from each other - they cannot share the same buss inside the panel. Seems that in your panel grounds and neutrals aren’t isolated from each other.
The load center which is energized from the PC is always the main panel. A sub panel can feed the main panel (or a portion of it) while distributing the isolated neutral and isolated grounds back to the Main panel bus bars along with the hot wires to circuit breakers. Just because the sub panel is back feeding power to the main panel does not mean the sub panel is now the main panel….
Each circuit on the transfer switch has 2 wires going into the main panel, a red and black. The red connects to the breaker you want to power. The black that was on the breaker is connected to the black from the t-switch. So power comes into main, goes to T-switch, then comes back into panel and out to the circuit in the house. There is a neutral and ground from the T-switch L14 plug that is connected to the neutral and ground bars, respectively, in the panel. These are a straight pass through from the generator. The transfer switch was made by Gen/Tran, which is now called Reliance Controls, based in California. They were owned by Generac for a time, and they still make my switch, under the name Pro/Tran. It is UL listed.
I believe you are correct, if I remember you should only have your neutral and ground bonded at the first point of disconnect, that would be your transfer switch auto or manual. ALL other panels should be wired like a sub panel. I just had to separate my main panel and add a larger ground buss.
@@bayouslots3143 - I know I’m correct, as you yourself discovered the ground and neutrals are to be separated in a subpanel. What’s unclear in this particular picture is why there are people who think the breaker panel hasn’t become a subpanel …
Its not coincidence that the cord end that connects at the generator had the issue (while the other end lugs were still tight). The generator shakes, and over the years the screws backed out. I wouldn't assume that the cord was bad from the factory. Thanks for the PSA, I'll go check my lugs and maybe even add some loctite...
Learn two things from this: 1 - Do a trail run before the power goes out. 2 - When you do the test, open all breakers. Make sure you get the proper voltage in the panel (or transfer switch) from both phase to phase and both phases to neutral.
Well, I guess this was a trial run. It literally happened in about 5 seconds. My understanding from what others have posted here is that both legs would be 120 until you start adding load. Unless the load is exactly the same (not likely), things will go south real fast.
Thanks for the story. Glad you figured it out, and glad no one was hurt. I'm sure it was a real head-scratcher. Now... to finish the explanation. When the neutral was bonded to ground on the generator (as well as at the service panel), the ground wire provided a return path for the current despite the disconnected neutral wire. So everything worked, although not as designed. When you unbonded the neutral on the generator, the ground wire could no longer provide a return path to the generator's neutral. I don't pretend to know exactly what fried your surge protectors but obviously it created an overvoltage situation. However, I think it would have been more appropriate and more helpful to title this video "Faulty Generator Cord Started a Fire!"
Thank you for the explanation. That is what I've been told as well. I know it will be nerve racking using the generator the next time I need it until I calm down.
Surge protectors are made to clamp voltage at a low enough level that your electronics aren't damaged by a very brief spike in voltage. But sustained over voltage causes the MOVs to get extremely hot. Plastic surge protector casings can melt or burn. Although the sustained over voltage situation is rare, I decided many years ago to get surge protectors with metal casings. I had seen an over voltage situation at work that melted a hole through the bottom of one of our surge protectors and burned the carpet it was laying on. Fortunately it was only the carpet directly under the hole and the rest of the carpet did not catch fire.
I remember when, as a heating contractor the first electronic controlled furnaces appeared. I was installing one and upon testing it wouldn't fire and shut off on safety. I fiddled with the thing for over an hour and finally got on the phone and called the manfactures engineering dept. The told me to check the polarity of the black and white wire coming. Come to find out the black was the neutral and the white was the hot leg (+). I wired them backwards and let the customer know in case of any future issues. Polarity has become quite critical. The grounding when using a genset is more than confusing to the average user and has been the cause of many a mishap.
Thank you for the lesson. About to install an interlock kit and buy some cables for a new generator. Will definitely be checking the connections all around.
Your description is a little confusing. What happens with a missing neutral is that the only path for current to flow is between the two hots. There is no ‘phasing’ issue going on. Basically what you had was unbalanced phases, ie the load on phase A was different than the load on phase B. All the current is flowing through all the loads on phase A and then flowing through all the loads on phase B. If they aren’t matched, then the 240V from the generator (voltage across the two phases) isn’t evenly split, so the voltage loads have on phase A might be say 180V and the voltage on loads on phase B is 60V Think of hooking two mismatched lightbulbs in series, say a 40W and a 100W and connecting that to 240V. The 40W bulb would see a much higher voltage than 120V and would quickly burn out. That’s why the problem got worse as you started switching more circuits in. Had you switched all circuits at once it’s likely the loads would have been relatively balanced and you wouldn’t have discovered this issue. All that said, throw any of those surge protection bars in the garbage immediately. They are a faulty design in in that situation then starting burning. You NEED protection like that to be self fused, those are absolute junk, and frankly shouldn’t be permitted to be sold.
My electrical knowledge is limited to basic wiring. I described what happened as best I could, based on what I was told. I don't understand why those surge protectors reacted the way they did. I've been using APC products since the early 90s, they've always been considered a top brand. It's hard to know what to have confidence in for an average person, I think. When I switch over to generator, I flip one circuit on each side of the switch, trying to keep the load equalized. It was very scary, I'm glad it wasn't worse. Thank you for posting!
Nothing faulty about the surge arrestors. They were used outside their designed criteria. With a broken neutral you get an imbalance in voltage, exactly as you described. But a surge arrestor can only absorb so much energy and normally with a connected neutral it would have tripped a breaker under a sustained over voltage condition or the surge is momentary. But in this case with no neutral and the current flowing through the arrestor due to a higher than normal voltage AND flowing through a device(s) on the other phase it limited the current to less than the breaker. So the arrestors were clamping and flowing current far longer than they would in a correctly working system. Even with your idea of a fuse, the current may not have been enough to blow whatever fuse you installed, since these were probably feed with a 15A branch circuit to begin with.
2:37 OH MAN those models LOVE to do that when “protecting its load.” I worked in IT at a community college a few years ago. We had a TON of these that looked exactly like this in one of our largest buildings(happened to be administration! Lol!), we had TONS of equipment and cameras go offline and not come back up. We were a little confused until we got into the office Monday morning after spring break to find that the utility replaced the pad mounted transformers and accidentally doubled the voltage somehow and so all of the 120v surge protectors burned up EXACTLY like the one seen here! 2:37 all of the computers that were plugged directly into the wall were fine because they could handle 220-240v. We ended up spending like $35,000~ I believe replacing all of the power strips and old crappy 120v power strip style APC battery backups from the same era. I’ll admit, they sure did their job! Albeit not in the most elegant way possible. 😅 The other surge strip models from APC & Eaton/Tripp Lite were perfectly fine so if you ask me APC made a bad product and refuses to do anything about it or admit it. They all burned up so badly I have NO CLUE HOW NONE OF THE FIRE ALARMS WENT OFF!!! All of our Eaton battery backups were fine as they shut off their internal input breakers and remained on battery/off until the proper voltage was restored. Can’t say the same about that generation of APC battery backups though…
The generator survived the experience? The people who say hire an electrician for everything must be rich. I do dyi because I'm not rich and when I've hired electricians for major projects they haven't impressed me. Thanks for the info.
The generator survived and appears to be unfazed. Its main breaker tripped about five seconds into the event. I've always been a DIY'er with pretty much everything - houses, cars, motorcycles. If I had to pay someone every time you needed something done I couldn't afford half of the things I own. Nobody's perfect...not even certified professionals.
@@user-gq2vn1xj2r Thank you. It took me a couple weeks of researching and asking questions, I was determined to get to the root cause. Definitely scary stuff.
100% this was caused by a floating neutral. In Australia we use three phase and not split/2 phase like North America, however the outcome is the same. The most loaded phase goes low and the lightest loaded phase goes up to the phase to phase voltage of 415 for us. If my eyesight serves me correct, the smoking gun is the wire ends in the female lead socket, they were tinned with solder, and absolute no no! Copper has decent spring tension and will maintain a tight bond under a screw terminal, if the conductor strands are tinned with solder, the lead will slowly flow away from the pinch point with time and become lose. I have seen this more times than I care to remember and always go off my nut when I see people doing it. I was next to a piece of equipment that lost its neutral some time back, it was like firing my 44 magnum without hearing protection, I traced the fault to a lose neutral that had indeed been solder tinned and worked lose with time.
I had a small power strip that I found had the hot and neutral reversed (I was getting buzzing/noise in my 40" monitor plugged into it). I had used it for decades. I opened it and swapped the wires (and tested it... and all my other strips as well, with a tester like you have).
Having seen many pictures of surge protector strips that melted down, some resulting in a fire, I have decided that I will only buy surge protectors that are in a metal case! A good one is fairly expensive but a lot cheaper than the deductible on the insurance policy. Plastic outlet strips that do Not contain surge suppression don't worry me as long as I don't load them heavily.
that APC unit gave its life to try to protect what was plugged it to it. the problem is that all things have there limit. if that was all you lost you were very lucky. i have seen floating neutrals take out everything in a house including refer, washer, dryer, microwaves , TVs and more. the more load differential between L1 and L2 the worse it is.
Yes, actually that's how surge protectors work. They short out the line when voltage goes to high. If the breaker does not shut off, it will just burn itself up. A surge protector is just a device that has high resistance up until a certain voltage and then it drops resistance rapidly acting like a crowbar circuit (it shorts out supply). It's a little $0.10 device called a varister that sort of looks like a fat ceramic capacitor with two legs and its just soldered onto the hot and neutral and in some strips another is soldered between hot and ground. The reason why is burned up is because it was unable to trip the breaker.
@@tomschmidt381 Surge protectors dont always have current protection. Most don't. The switch on top is just a plain rocker switch with a little backlight. If it has a circuit breaker it will be a little black pop out style on the side like what some appliances have. The average surge strip you buy at walmart has zero protection besides the ability to short out when overvoltage occurs. So if you have a surge, the strip shorts out to clamp the voltage and will continue to do so until the circuit breaker in your house trips. If that does not happen, then the strip just self destructs.
Excellent video. You can never be too careful. Great job. Some would have left the other video live and done nothing. You immediately took it down when you had a problem and then had the thoughtfulness of other people to talk about it and walk us through your solution. Bravo and Thanks.
When you drop the neutral the loads on one phase are put in series with the loads on the other phase. If they aren’t balanced evenly you will get a high voltage on one phase and a lower voltage on the other. Think 240 across 2 different value resistors in series. The higher resistor will have a higher voltage drop than the lower. Same current through both.
I have an interlock on my main panel. The generator I use is a Honda EU7000 that has a Floating neutral from the factory. The Honda EU and EM series generators have floating neutrals. The EM series have bonded neutrals.
In order of electrical contact quality you have: 1- soldered. 2- machine crimped. 3- spring loaded. 4- hand tightened. 5- hand crimped. with proper tool. 6- hand crimped with non specialized tool. If you can yank the wire off the terminal with a good tug, the connector fails. Regardless of how it's made.
Earthing and diverted neutrals is also becoming an issue here in the UK for 'similar' (though not exactly the same) reasons. There's a lot of discussion about earth disconnects for EV vehicle chargers where (here in UK) there can be lots of other electrical services near the point of charging that end up (especially under latent fault conditions) with different 'local earth' potentials which is cross bonded produce large unexpected currents (the latent fault becomes potentially patent/obvious!). Obviously if there is a local 'fault' causing your outage, you can have a similar unbalanced earth issues. (edit: e.g. have a look at `e5 group`s webinars on diverted neutrals)
Power bars like the one in the video use a simple device known as an MOV (metal oxide varistor) connected between line and neutral, which does nothing until the voltage spikes above a certain threshold at which point it becomes a dead short. This short then trips the circuit breaker in the power bar. Many of these breakers are not very effective against dead shorts and weld themselves closed. If you are lucky the house breaker will then trip. There is a large selection of surge protectors out there, Choose them carefully, there are a lot of cheap imports around. I personally use computer grade UPC's for all my electronic gear.
Wow! Had sort of a similar-ish thing happen nearby lightning we suspect wasn't home at the time came home to find most of our power strips zapped. Yeah supposedly they wear out overtime that's why you need the ones with the Protection LED assuming they're not just straight wired in. Ended up losing the power adapter for a TV converter box and not the CRT TV the cheap CRT TV! And about a dozen power strips. I salvaged the cords they were still good. I went through every power strip that I can opened and checked the inside. I have just started getting in the habit of anything that is Electrical is inspected before use after purchase. I picked up a inverter and discovered that they didn't slap the circuit board in properly so it was warped.
Thank you for this video. Just a follow up question: Even though the right thing to do with your setup was to float the neutral, do you think the fire would have still happened (regarding the cord problem) if the generator would have had the neutral bonded?
The neutral had been bonded to ground and I was using that setup without a problem. Little did I know that the ground wire was essentially acting as the neutral until I remove that bond, and then the crap hit the fan. 😱
Thanks for bringing awareness!! Will definitely be inspecting all cables as I am currently installing a transfer switch and generator inlet at my house.
You are correct in unbonding the Generator frame. Loose coonections are the true cause of Electrical fires. You should check the terminal screws on your outlets and switches, my expectation is that many will take a 90-120 degree turn , if your home is more than 15-20 years old.
I put new outlets and switches in my house. Didn't find any loose switches or receptacles but did find a couple that were so poorly stripped the wires were almost cut through and broke off as soon as I pulled the switch from the box. I tightened connections at the panel and found that all the connections on the side of the panel closest to the garage door were 1/4 to 1/2 turn loose. I suspect the greater temperature fluctuation near the door caused the connections to work loose over the few decades since the house was built.
Thank you so much! When I was running the generator at the end of the video it was in floating neutral configuration. That's how I plan to run it going forward.
Something you might want to consider if buying a 12" square ceramic floor tile to go under your power strips. The MOVs can wear out and short. A good strip should detect that and open the power. But better safe than sorry.
OK... Let me break this down for you. If the neutral is switched in your transfer switch, then you must keep the bonding jumper in the generator, because then it is considered a separately derived system. This main bonding jumper bonds the neutral bus to the ground bus and frame. However, if the neutral is not switched in the transfer switch, then you need to remove the jumper from the neutral bus to the grounding bus in the generator. The ground bus should still bonded to the frame, but not the neutral. In a nutshell, the 'main bonding jumper' should only exist in one place, and that is at the point of service. The way to tell if your transfer switch has a switched neutral is by the poles; most residential houses have a single phase two pole 240V service. If your transfer switch is two poles then it likely has a solid unswitched neutral aka (SN kit), but if it is three poles then it is a switched neutral. If you are just not sure what you have, then leave all the bonding jumpers in, it won't meet the code but it is much safer than removing the main bonding jumper when you need it.
Thanks Stormy. The transfer switch just passes the neutral from the generator straight through to my panel, it is not switched. I have removed the bonding jumper from the generator. I have confirmed with a meter that the neutral and ground at the generator are not bonded. When I plug in the 30 amp cable to the transfer switch and generator, the meter shows the bond is back. The thing is, I have read so many horror stories here of what loose neutrals can do that I almost wonder if it would be better to just bond the generator, even though it's not code compliant. In my head, I know that's not the right thing to do, but living through this was not pleasant.
@@bluesriderDF It does not meet code but half the generators I service are bonded and on and an unswitched neutral. I have never seen any of them with an issue because of it.
That is the problem with MOV surge protectors in a plastic case. They are inherently dangerous, and will catch fire upon loss of neutral or prolonged over voltage. Burning plastic can quickly set fire to anything nearby. It is safer to get a plain old power strip that does not have surge suppression. The NEC now requires whole house surge suppression, so those point of use units are redundant anyway.
CORRECTIONS, thanks to the folks who commented below:
0:08 - Unbonding is removing the ground strap that connects ground and neutral, not ground to frame.
3:25 - The generator is a single phase, so it couldn’t run “out of phase.” Instead of 120v going to each leg, most or all of the 240v was going to one leg, and almost none to the other.
I just removed the ground wire from the plug terminal that goes into my generator and left my generator bonded. That way I can still use it around my property remotely and have the bonded ground.
Each leg always has 120v to neutral. The 240v is across the two legs without a neutral. With a missing neutral, 240v is present across the loads of the two legs in series. Since the loads will not be equal, the voltage drop across devices on each leg is different and some devices will see too high of a voltage and may burn up as happened with your surge suppressors.
@bluesrider. The 240v cable between my generator and box plugs into the generator carrying the 2 hits, ground and neutral. When the wires from the female receptacle on the generator go down to where you unbounded your Westinghouse they connect to their respective tabs, which are then bonded. What’s the difference between removing that jumper bond wire on the generator and having your transfer switch only connect the neutral, 3 wire config, and me removing the copper ground wire in the cable from the male ground pin on the plug?
I don’t have a transfer switch I’m wired into a 50 a breaker in the main panel and manually switch off the grid after the Power goes out.
(Unbonded)
For 20 years I’d been connecting my bonded generator to my main panel with no problems. After seeing a James Condon video on this topic I unhooked the cable ground at the plug. Had a power outage and no problem, but I don’t want any problems. I just don’t see the difference between what I did with the cable and unbonding inside the genny. I have an 8’ ground rod right below the main box I plug the gen into.
@@jtjones4081
That was very foolish . Now you have no ground to the generator. If there is a ground fault the circuit breaker on the generator won't see it and it will burn until the wires burn through. Not to mention various code violations.
A 120/240 generator cannot go out of phase as it only has one phase. What probably happened is loosing the neutral caused the power being consumed to find an alternate route back to the generator. Meaning that instead of 120 -N - 120. you had for example 50-N-190. Those surge protectors operate by clipping any over voltages. depending on the specific component (a metal oxide Varistor is usually used and rated around 140-150v) will cause the Protector to try to protect. IN this case the Surge it was seeing wasnt due to power issues as a fault in the wiring of the cable. Glad you found what caused it.
Thank you Matt, I appreciate the explanation 👍
Over revving will also clip them MOV's, Diodes, trans, IC and wipe out most battery chargers, computers, digital equipment etc. 130v at 65 hz starts driving shit crazy and turns the Genie into smoke
Your partially correct, You will read different voltages at the loads but keep in mind that the generator still only does 120vpk 240v p/p If you have equal loads say two identical fridges can you run them in series no neutral? Or say have 120v compressor in series with a deep freezer in the garage? Will one run and not the other?
Ahhh the age old question? Yes or no, in or out, up or down, right left, 1/0, will one burn up and not the other? Keep in mind what is in series and what is in parallel, isn't electricity fun.
@@bluesriderDFhe's on the right track but his explanation is erroneous. The lost generator neutral caused a backfeed through all the branch circuit neutrals putting 240v on your 120v equipment.
@@ianbelletti6241 No. he is spot-on.
It does not put 240V on your 120V legs, it depends on the impedances of the connected loads at any given time.
It can vary between 0V and 240V on a leg (and the converse on the opposite leg).
I did not see any errors or typos in what he stated.
Definitely a classic example of a floating neutral. A couple years back went on a service call in a late 1970s home, where the TV, DVR, DVD player and stereo system in living room smoked up so bad it set off the smoke detectors in the hallway and master bedroom after a 1500 watt electric fireplace had been running for over an hour, plugged into a different outlet on the other end of the living room. Come to find out, all the receptacles were backstab connection and part of a multiwire circuit (L1 & L2, sharing a common neutral) and the neutral burned up on a receptacle upstream, making everything downstream into a series 240V circuit and depending on the load balancing, voltages applied accross the load can range from nearly 0, to nearly 240. Also pointed out to the homeowner and corrected, the two single pole breakers controlling the multiwire branch circuit, by installing an identified handle tie to ensure that if either leg trips the entire circuit is dead, protecting anyone working on it thinking its dead when in fact one leg is still hot, evidently this wasn't required when the home was built.
This whole catastrophe could have been avoided, had article 300.13 (B) of the NEC been applied which states that for multwire branch circuits, the continuity of the grounded (neutral) conductor shall not depend on connections to receptacles, lamp holders and so forth, where the removal of such devices would interrupt continuity. What this means, is that the neutral on those receptacles should have been connected via a pigtail
I HATE backstab receptacles!!!!
Always use spec grade clamping connections, or at least use a J hook connection.
Don't confuse neutral with ground. Ground only carries current when something is wrong. Neutral carries all the unbalanced current between L1 and L2.
That unfortunately isn't as true as you would normally hope.
With the increased use of better protective earth connects you can easily get a competition between the supply company's attempts at providing a low impedance neutral (truly reference to earth at the generators, subs, and transformers) and the parallel earthing impedances for the multipoint safety protections.
It gets worse in three phase supplied zones where the individual phase takes are unbalanced and the protective earth-neutral bonding enhances the diverted neutral current. It will depend on your generic location as to whether the local buildings and construction styles will make it more or less likely , and not forgetting 'fault' conditions.
This was one of my arguments for not unbonding my generator, having more or less a redundant neutral. In the end I did unbond it and have not had any issues, but this video shows the importance of having a good solid connection all the way around.
Why did you unbind it if you were for bonding? This topic is so confusing, nobody has a definitive answer. I haven't had an issue running my generator bonded.
@@billyfowler9423
Using the ground as a current carrying conductor, bonded at both ends, is a serious code violation.
The surge protector did catch on fire because it had a very /low/ resistance. Not high resistance. The MOVs inside go low resistance when exposed to over voltage, and they are supposed to short out and blow your fuses. It can be dangerous supplying power from a generator as it might no be able to make enough short-circuit current to trip thr fuses.
The following is an experience I had a friend asked me to look at. What I found out I had never heard of.
When turning on several lights in the house, the house lighting would slow flicker or surge up and down, get brighter then dim. Everything checked out to be normal throughout the house, so I assumed it was a lost neutral somewhere in the house. I have years of experience in residential, commercial, and industrial electrical field's but I'm not a licensed or insured electrician and screwing with a lost neutral can burn down your house, so I recommended having a licensed and insured electrician take a look. They did. The electrician found everything was normal throughout the house also. Eventually he found the problem. It was a mixture of different brands of LED light bulbs throughout the house causing the fluctuation. My friend changed all the LED light bulbs to one brand and that fixed the problem.
Wow, that's wild.
I have the same problem. Thx for the tip.
Before you unbonded your ground at the generator, your neutral current was flowing through the ground conductor in the extension cord and the bonding jumper. So it was a related problem and unbondining your generator is correct. A ground rod would NOT have mitigated this problem even if you had connected it directly to your service entrance rod. That would have made the neutral current flow through your ground rod wires.
I agree. Thanks for posting!
I think the biggest lesson here is to always test before you need it. After making any changes, test and verify.
Glad you weren't hurt.
Thank you Mike. The cable tested okay as far as continuity, but failed when under load. Definitely learned something here.
@@bluesriderDF That's rough. A continuity test is usually enough.
My first thought after all the troubleshooting was "why didn't you test the cable first since it's the easiest? "And then I realized I would have followed the same process as..."it's just a cable and how could THAT be the issue?"
That is truly scary. Thanks for posting this video. Reminds everybody we should never take anything for granted.
You got that right! Thanks for commenting.
there are a lot of lessons in this video. This could be a whole lesson for an apprentice or journeyman refresher course. Open neutrals are something we run into a lot and are often times at the service point. Interesting video and I am glad that you are safe!
Wow, thank you so much for your comment, I really appreciate it.
That generator bond covered up the cable's unconnected neutral. By removing the bond, there was no more neutral. All unbalanced circuit loads would get up to 220v pumped through it . Only balanced loads will get 110v.
Exactly.
Side note: 250.30 of the NEC requires separate bonding wire to the service panel when connecting a generator in this situation if the neutral remains connected to the grid. However, if the transfer switch also separates the neutral from the grid, then the generator needs to be internally bonded.
The neutral is never connected to the grid as it's generated by the center tap of the line transformer on the pole
Interesting. Thanks for sharing. Lost neutrals and meltdowns are not something I normally associate with generator usage. I made up my own generator extension cords. After watching, I'll open them up to absolutely sure connections are still snug after 2 years...especially the neutral.
That sounds like a great plan. Thanks for posting!
I agree, I will check my cord.....
I swear I said to myself about 10 seconds after you suggested an immediate fire, "His cord has a faulty neutral, and the ground wire previously provided neutral because they were bonded at the generator."
I'm glad you and your house are still standing to talk about it.
Thanks man. Yup, that's what happened.
When the neutral get loose like that one leg goes high, the other one goes almost to zero volts like you said on the video and everything is connected in series between the two phases. The culprit is the loose neutral connection. It can also happen on the utility side of the installation.
Yeah, there's nothing like learning in real life, LOL. This is scary stuff.
Also known as a floating neutral.... VERY bad!!!
Thanks for sharing your experience. Great information. I am wondering if the constant vibrations of the generator ended up working the screws loose over the 20 years.
It was actually loose at the side that connects to the transfer switch
Thanks for sharing on your experience with this!!!! I'm an electrician, have installed many different types of home generator connections and transfer switches, panels , etc. But that Generator "Cord Set" some call it could be a failure that me as an electrician may not catch in my Testing, after an installation. If the home owner replaces a cord, and gets a bad/defective cord set, the result could be very bad. So important to validate/inspect/test the cord set as well. God bless
Thank you so much, I appreciate your post.
If you haven’t already done so, I’d recommend a whole house surge protector. Although if it’s installed at the main panel and you are running over the transfer switch circuits only that would probably be bypassed.
One thing I’ve done at my house is install a voltmeter at where the generator goes into the transfer switch. That way I could see abnormal high voltage if my neutral was loose.
I use a generator interlock on our service entrance. Like you I added a generator status panel next to it that shows current and voltage on each leg, and frequency. The generator is electric start so the status panel includes a DC voltmeter to monitor battery voltage and verify the battery maintainer is working properly.
I also recommend installing a whole house surge protector in addition to point of use ones and also at hard wired devices.
The same exact condition that you experienced occurs all too often when utility feeds coming into a building looses the neutral connection, usually at the pole due to windy conditions or sometimes in the meter pan due to corrosion. The voltages go out of balance and cause all kinds of grief. The first clue is when some lights are dimming while others are too bright and subsequently burn out. There isn’t much that can go wrong that is worse than this.
Yeah, scared us real good.
I'm a roadie, and I never connect my equipment to a building's power or to a generator without first metering voltages and checking continuity (or expected lack of continuity) between ground and neutral.
I've been asked by venue guys a few times why, and this video in part shows why.
You probably have had the neutral on that cord not functioning for the entire time and when your generator was in bonded mode the return path to the generator was provided by the ground wire on the extension cord. When you unbonded your generator you removed the ability of the ground wire to act as the neutral return. So not coincidental that unbonding the generator eliminated the neutral path and caused the issue.
Or maybe it worked loose over time, not sure. Either way, definitely a bad situation.
I suspect this is what happened to me. A few years ago we needed the generator, I plugged it in just like I always do and the Keurig coffee maker took a hit. Seems like we lost other electrical appliances also. Inspection of the extension cord showed a loose wire. I don't remember which one it was. But I suspect it was the neutral. I tightened all wires in both ends of the cord and everything began to work correctly. Thanks for posting this, it helps me understand what I experienced.
I guess you were fortunate too.
This is why I build my own cables. I see you went the molded route and that's putting a lot of faith that it was built well.
What gets me is when you know there's a huge amount of good cabling, but all those little mistakes make it all not worth the risk :(
Well, it's UL Listed, and I like the fact that I can see the connections through the clear plugs. I've tested it and everything looks solid.
Thank you, thank you, thank you.
I have been stressing about the floating neutral question for about a month now and I am almost finished with the complete installation of my system.
You answered my questions and really gave me down to earth answers.
I'm good now.
Thanks man.
Well you just made my night. 😊 You are welcome!
"gave me down to earth answers." I see what you did there.
I know the video is from Jan 25 and you may not get notified about this comment but I will leave it for others to see. When you do not have a neutral back to the power source in this case, the two hot legs will try making a circuit through the neutral how ever they can. In this case the MOV's in the surge suppressors were allowing the current to flow between the two hots and try to balance the load. The problem was that the MOV's in both power strips did not like the current flow through them and burned out. There is a reason a good electrician will setup a generator system to have the important systems on generator power and others like TV's and non essentials will be left out. In this case the only things that should be on a generator for a power outage is refrigerators, freezers, furnaces and well systems. Options would be lighting after that, but it should be in necessary areas like kitchens and maybe garages with the door opener. If you want to power the whole house, then I would suggest getting a whole home generator setup and if you want to go cheaper on the setup, then get a load shedding system. The only reason you should break the neutral ground bond in a generator is if the neutral at the transfer switch is using the neutral and ground connections in the main panel or at the main disconnect on the premises per NEC code 250.34(A)
I read all these comments, thanks for writing that up! It was educational, and i'm sure will help others. As you said at the end, I am using the neutral in my panel, which is why my generator is floating. A whole house generator would be nice, but don't have the funds for that and honestly, we don't really get that many power failures. Watch, now I'll get another week-long one. 😮
In the case of using an interlock kit (essentially a manual transfer switch?), does the code and/or mfg call for breaking the generator neutral/ground? Also, when and why are you required to drive a ground rod for a portable generator ?
@TheRobWay1 There is only one call for a ground rod on the generator, and that is when the generator is isolated from a main distribution panel that has no grounding. If the generator is attached to a main distribution panel that has grounding, then the cable that connects the power from generator to panel must have all wire connecting lines, neutrals, and grounding. If not connected, then you are violating NEC code for safe electrical conditions.
Be advised with your surge protector the MOV will blow and protect on the first fault, but instead of just not passing current ( open circuit) then the surge protector goes into bypass and you have no protection which as far as I am concerned is a huge safety issue
I'm an electrician retired after over 40 years in the craft. The reason that the voltage went too high on those Surge Protectors is that without an intact neutral the voltage will fluctuate with the amount of loading on each of the generator's energized conductors. The most heavily loaded side will have the reduced voltage and the lightly loaded energized conductor will have the higher voltage. The greater the difference in the loading the greater the difference in the voltage. In your case the load must have been markedly different on the 2 energized conductors and that produced a destructively higher voltage across the lighter loads which must have included those surge protectors.
Why that happened is that in most cord sets of under size 2 American Wire Gauge (AWG) all of the conductors are the same size including the Equipment Grounding Conductor (EGC). Since the Neutral Conductor of the cord had an open connection at one end it was not carrying any current. The EGC (Grounding Conductor) of the cord had been carrying the imbalance current from the Grounded (neutral) busbar of the panel to the frame of the generator. The Main Bonding Jumper of the generator windings had been carrying the unbalanced current of the different loads the rest of the way from the generators frame back to the center point of the generator's windings. Under those circumstances both energized conductors carried their portion of the load current while the Equipment Grounding Conductor (EGC) carried the difference between the current flows on each of the energized conductors.
Theoretically that is the wrong pathway for that current to return to the center point of the generator's windings but nobody consulted the electrons about our theory and they don't give a tinker's dam about what we think that they should be doing. Electric current does not take the path of least [resistance + reactance =] impedance. Impedance is the sum of the resistance and reactance to the flow of AC current. AC electric current takes all of the pathways available in inverse proportion to their respective impedances.
Once you unbonded the generator winding's electrical mid point from the frame of the generator the difference in the current flowing on the 2 energized conductors had no way back to the source. That shifts the electrical midpoint of the generators voltage away from the heavier loaded portion of the generator's windings and toward the lighter loaded end of the generator's windings.
There are devices that are usually used to protect recreational vehicles (RVs) from failures of the RV park's electrical system. One of the things that they do is disconnect the cord from the power source if the neutral conductor develops a high impedance or goes open. Using one of those plugged into the 120/240 volt plug of the Generator will disconnect the cord from the generator if either of those conditions were to develop.
Tom Horne
Thanks for the excellent explanation Tom, very thorough.
I have a question for you Tom. Would you advise against removing the bonding jumper of the generator when tied in to a residential panel that’s bonded itself ?
@joshe9518 If your panel is bonded, that's why you should remove it from the generator, so you don't have more than one N-G bond in your system, per NEC code.
So, in a nut shell, don't eff with the generator and its factory settings and staging. Leave it alone and it will do its job.
@@243wayne1 Um, what?? The National Electric Code says otherwise.
I am not an electrician, but have been doing home renovations for 30 years. I installed a 120 volt Coleman RV heat pump in my kitchen ceiling. I also installed a dedicated duplex outlet for this purpose. However, when I turned on the heat pump the first time, it ran but was noisy. So I shut it off and went to inspect the heat pump itself. The motor case was extremely hot. I troubleshooted the possibilities, and found I had connected the neutral to the neighboring breaker, so the circuit was 240 volt. OOOPS.. Five years later, by some magic, the heat pump is still working. Oversight happens to everyone, so your extension cord failure is not a surprise, but glad you figured it out. (PS: during the course of home renovations, I found many many electrical and plumbing faults, done by the "PROFESSIONALS".)
I feel like no good deed goes unpunished as they say. I did a lot of research on this ahead of time, and I really thought I had everything covered.
So this happened to my house.. the neutral fell off the transformer. This transformer fed my home and my neighbors, we both had our AC on. My house was the first in line, and the first breaker down from the service connection went to the living room. Let’s just say it found a ground, arched through the outlet and caught the wall on fire. Been out of my home for almost 6 months as they do repairs and replace/paint everything
SIX MONTHS?!?! That suuucks!!!! So sorry. No one got hurt I hope. Hopefully you get your home back soon.
Thank you very much, we need more people to learn how to figure things out. Everybody in they're life will need to have this type of reasoning in order to survive, can't just leave it up to somebody else all the time
Thanks again for teaching people.
Thank so much, I agree. My father and grandfather were DIY'ers, they thought me so much.
Very common issue on RV's that have 50a service connection. Im RV service tech electrical specialist. Old cords or old power pedistals at RV parks. For various reasons if the neutral line fails plug, cord, etc and a low resistance appliance like the hot water heater kicks on electric causes a huge imbalance on the two lines of 120 and typically fries a bunch of stuff in seconds.
Holy smokes! Literally!
You are like a electrician detective. Glad it was only a couple of surge protectors that burned and not you home.
LOL, thank you! I'm hoping things are uneventful going forward!
I believe that the connections were tight from the factory, but got loose over the 20 years the cable was in service.
Screws get loose over time from vibrations, so I believe that all the rough handling that the cable endured (specifically the plugs) from being dropped and dragged around made the screws loosen over time.
It's a good reminder (even for myself as I haven't thought about this until now) to check all the cables that have plugs mechanically connected to them (with screws, not soldered on and potted in rubber fom the factory).
I will never know if they were tight at the beginning. But i'm never going to use a cable like that again. Soldered and molded from now on.
So basically the lesson here is that it takes maybe 15 seconds with a meter to check the continuity of your cord. And probably 99% of us have never done that. We all just assumed that if we didn't make it up ourselves, that it came from the factory correctly wired. That is a dangerous assumption, more dangerous than most of us realized. Thanks buddy, I am going to go get my meter out right now.
Yeah but even then, some things only fail under a load. It was a crazy experience for sure. Thanks for posting.
What I have just dealt with is a dropped neutral. As pointed out already, the current tried to find another route. If it's balanced between the two hots, it could operate without too much issue. However, if it goes out of balance (and that could be the difference of one lightbulb being on or off) it changes voltage on each line,(As already pointed out). Potentially feeding 220v to your appliances and lighting. It looks like Those surge protectors detected the higher voltage, saving your tv. Bulbs can explode and tvs can start arcing, but luckily you avoided that.
Yes, I was incredibly fortunate.
Nice detective work. Thanks for the info.
Thanks so much 👊
I had a series arc fault that started a fire in my basement. The load was a 120V 10A steam humidifier fed from a 15A outlet through a 25ft 14ga extension cord. It ran this way for many years. The cause was a poor connection at the female end of the extension cord. The arc persisted for a long duration and it burned itself open without tripping the standard 15A breaker. It started the wall on fire. Fortunately I was able to extinguish the fire before it got out of control.
The solution: I ran a new dedicated 15A AFCI circuit to a GFCI outlet mounted clear of any flammables to feed only the humidifier.
Running continuous unattended high current loads through manufactured cables or extension cords is hazardous because the connections in such cheaply manufactured cables cannot be inspected and verified.
Arc fault circuit protection is my new best friend. 😊
And all extension cords get side eye from me now. 😒
Oh man! Glad you caught that. I had this house built and I'm familiar with it. When you buy somebody else's place, you have no idea what they did. One thing I wish they did here was use 12ga / 20amp for more circuits, especially in the garage. That might actually be required now.
As others have said, thanks for sharing the story and glad everyone is ok. Sharing these experiences helps others.
Thanks so much. That's why I posted it, I'm glad it's getting some views.
Thanks for taking the time to make and post this video. I had this happen to a friend of mine as well. It blew out a GFCI wall socket in the master bath, and in the master bedroom, a TV and a clock radio. Oddly, everything was isolated to his bedroom and master bath, though the open neutral was on the generator-to-transfer switch cord.
Nice job finding the problem. In my home the surge protectors are in steel boxes next to the fuse box. Yes I still have fuses on the old part of the house. I never, ever use any plastic electrical devices like a UPS, surge protector etc. I had a problem with power and it was due to a corroded aluminum wire feeding my panel. When we had a hurricane and lost power I replaced all those wires. Been good ever since.
Thanks you for posting. I definitely prefer steel over plastic. Everything works until it doesn't, right?
The best whole house surge protector is the Ditek brand they have a different MOV called a thermal protected MOV. What happens during a surge most surge protectors MOV's sacrifice themselves. Which is what you want, but the problem is if you get a 2nd surge now you have no protection. Ditek because thermal protected MOV can continue to protect they don't self sacrifice. It installs easily into your main panel.
Personal experiences - the best lessons for those of us who are still learning! Thank you!
You're welcome!
Thankyou for the reminder to check your generator cords because you can get a defective cord and things do wear out as well as the fact that terminal screws can sometimes loosen.
Even if you had a bonded neutral and ground on the generator it still may have caused problems if the ground is also loose in your plug.
That's true.
Without a neutral and an unbalanced panel the leg with the biggest load will be the return for the light loads on the other leg. The less loaded leg will get the high voltage and the more loaded leg will get low voltage. The neutral takes the difference in voltage balancing the circuit. So that surge protector probably saw about 190 volts
Makes sense
Watch out, now all hardware on your electrical system which contains MOVs may have had their lifespan shortened.
2:31 These surge protectors are armed with metal oxide varistors which are simply components in parallel with the mains which will drop in resistance when exposed to transient spikes literally designed to short circuit and “neutralise” “clip” the spikes but with no ground on the generator it’s clear the open neutral put significant disruption in the MOV causing it to clip and short the mains.
Yup. I will be going through and replacing those.
@@bluesriderDF
They're also referring to your appliances themselves, because their power supplies often have MOVs and suppression capacitors rates for a specific voltage for filtering as well. So, computers, TVs, washing machines, microwaves, etc, ALL have probably had their power supply lifespan shortened. If you have things breaking left and right a year or two down the line.... it was probably that power spike that caused it. If you were lucky though, the powerstrips that burned took nearly all the load and gave their lives to clamp the voltage down. Those components are designed to short as long as there's still a voltage spike. Chances are you'd be replacing a lot more devices if you didn't have them plugged in, so thank APC for making fairly durable equipment. I always recommend their stuff.
@@theLuigiFan0007Productions Time will tell I guess 😢
@@bluesriderDF
Yeah, hopefully things took the path of most luck and least resistance. Good thing you found that though, that cable would have raised hell down the line regardless. Perhaps schedule a routine cable inspection, generators vibrate, and it probably loosened itself, now that I've had a day to think on what I saw in the video. Hey, you got it straightened out, and your system should be reliable again. Best of luck, stay safe, and have a great day.
Good info. Thanks for sharing !! So glad the damage was minimal!!
Ride safe!!
I wonder if it started off tight, and the generator running loosened it up? Good diagnostics!
That is probably the case.
Not likely. The female end is the one that had the loose neutral which plugs into the transfer switch.
@@chrish7927 It was the male side that was loose.
@@bluesriderDFI just watched the video again and it was definitely the female end that pulled apart and the connectors came right out of it.
@@chrish7927Oh, my bad then, sorry.
Thank you for posting this video, in all honesty I have never even given the cord a second thought , but I will from this point forward. thank you again..
I appreciate the feedback. A lot of people have roasted me. I just wanted others to be aware of it.
+1 on this comment. I’m a licensed electrician, and I f-ing guarantee you that better than 50% of electricians wouldn’t think of the cord. I am in a lot of electrician discussion groups and electricians will be the first to tell you that they are abusive, know it alls. I, on the other hand appreciate any opportunity to learn and grow, and that starts with humility. This is a very valuable, educational video and could potentially save lives.
@@TheRobWay1 Wow, thank you so much!!
I am glad you're okay and that it wasn't a lot worse as, from what you said in the video it could have easily have been so much worse.
This could have all been avoided it there wasn't that stupid split-phase system as there would be only one possible voltage and loss of neutral would have meant a loss of power rather than massive overvoltage and fire. If there was only 220V, which could be done, things would be a lot simpler.
Thanks so much. Yeah this scared the bejesus out of me! I don't think I'll ever relax while a generator is running in the future.
This was helpful, my new generator (that hasn’t even been fired up yet) is sitting outside waiting for everything else I’m needing to use it to arrive and you’re reminding me to test every aspect of it, the heavy duty cable that came today, etc before I trust any of it… Thank you
Good plan! Thanks for posting.
I have experienced loose connections at the generator end plug that I suspect is a result of vibration from the generator. These connections need to be checked regularly.
Wow, who knew? I really like the new cable. Because everything is soldered, sealed, and I can see it.
Thank you for everything!
I’m glad you and your family are safe 🙏
Same to you!
Thanks for your help.
That will give me another item to check when I put in a generator.
Your split phase imbalanced load could not get back to center tap on genset windings and found a path via N-G surge MOV’s. Typically surge protectors have a thermal fuse that should had taken it out of the circuit. That being said. It could had came back through you if you were a lower impedance path. Would recommend reinstalling that genset bond strap and keep a better eye on your connections and balance. Also check your connections to earth.
It seems like having 2 paths to ground is "safer" even though not to code.
Excellent work with the diagnosis. Highly educational.
Thanks so much!
This information is invaluable. I’m currently in the process of having a transfer switch installed and have the same generator you used in the original tutorial.
Thank you for sharing this.
@@robertalvarez8128 Thank you for the feedback! This is why I put up the video.
Do not count your bus bars as phases. They are not phases only bus bar A and bus bar B same phase.
Very good content in your post. Thanks for sharing. Rest assured most of us do not think of checking the UL listed store bought extensions. Now I will.
From a UK perspective, I'd say they were anti-phase, so were 'different'. Each of the systems have their strengths and weaknesses ;-)
So, yes, that service cord was definitely the start of the issues. But the fire department was also right about the surge protectors doing their job, or at least attempting to. As you mentioned in the video and in more detail in your corrections note, you had high voltage on one leg and low voltage on the other due to the disconnect of the neutral. Search protectors like what you showed work by clamping the voltage to not exceed a certain set voltage, probably around 210 volts for your particular application. When a lightning strike or motor surge causes access voltage In the buildings, electrical system. A component in the surge protector called a MOV or metal oxide varistor clamps the voltage and prevents it from getting to your appliances. It does this by shorting current between Hot and Neutral temporarily until the surge dissipates. Normally, this short is only for a few milliseconds at most, But in your case, it was sustained because it was being produced by the generator. This resulted in the MOV(s) overheating. The first search protector you showed was too burnt to tell just where it started.. But the second one you showed, I could clearly see the MOV s on the circuit board, and yes, plural, there were several to increase capacity, and on the plastic shell, you could clearly see the melting starting directly below where the MOVs would be when the device is assembled.
You may have overcomplicated your thoughts enough to lead you down the rose colored road. A floating neutral is actually very simple. You have created two 120V busses that of course have 240 between them. Since the neutral is floating, now the 120V loads on each buss are in SERIES with each other, and depending on the loads on each buss, the voltage to the loads on each buss either rise or fall, depending on the amperage they draw. IE if you have two 100W lamps, one on each buss, in theory, they will operate "fine" But if you have say, a 60W and a 100W, the 100W will draw more current, and case more voltage to appear across the 60W lamp.
NOW ON THAT fact, you could easily notice this if you installed a pair of voltmeters across each phase. If the loads are badly unbalanced, or if the neutral develops a problem, the voltages will become more and more unequal.
I'm not sure that bonding / unbonding is a good strategy for safety here. THE GROUND AKA green circuits are NEVER intended for carrying current. They are FOR SAFETY in the event of shorts/ faults etc.
And, this problem really is not unique to a genset, either. Something like an RV cable could have suffered the same problem with a bad cord/ cap connection.
Don't forget that there are now a lot of RFI/EMC filters in all the consumer goods and they all leak current (typ 1.6mA) from the live to wiring earth (not neutral), so you can build up a leakage bias that makes makes the system take up an unexpected potential difference between the systems. They are never truly 'floating'. The surge protectors are also reference to wiring earth.
The ground circuits should be sized to ensure that they are capable of carrying fault currents large enough to trip fuses (old & new).
It all gets very confusing because "Earth" can mean many different things and the assumption of ideal wiring (zero ohms, infinite capacity) on circuit diagrams can give a false indication of reality (and local 'practicalities';-).
So bottom line is unbond the generator when connecting to your house panel as the manufacturer recommends, but make sure you have a good cable....correct?
Make sure you have good connections all the way through from generator to your main panel. Anywhere there's a connection, there's the potential it could be loose.
If you use a single leg (120V only) generator and neutral or live gets loose you will lose all power, maybe the plug or whatever other loose connection starts arcing and catches fire too.
With a two leg 240V generator if the neutral gets loose the 240V will be distributed among the different connected devices according to their power consumption, causing those with higher consumption to receive a too low voltage and those with low consumption to receive a voltage that is too high. But the neutral can also arc inside the plug or wherever it's loose and cause a fire.
I never do portable generators as separately derived services (SDS). I use a 2 pole disconnect and ensure the neutral and ground are bonded at the generator. I'm not saying you can't use a 3 pole and switch the neutral, it just adds unnecessary complexity without any return.
I thought that a separately derived system DID bond the neutral (such as a transformer)? If the ground is bonded to neutral at the generator, is current going back on the ground and neutral?
@TheRobWay1 you are correct, i got them mixed up. It is the reverse of what I said. if it's done as an SDS a 3 pole ATS is required.
5:57 If I am not mistaken, your transfer switch is the first “panel” that the electricity flows through, whether running on power from the electric company or from the generator. When that is the case, your “main” breaker panel is a subpanel, and it must be wired as a subpanel is supposed to be wired by code. The big thing that must be done in a subpanel is ALL ground wires and ALL neutral wires have to be isolated from each other - they cannot share the same buss inside the panel. Seems that in your panel grounds and neutrals aren’t isolated from each other.
Mskes Sense
The load center which is energized from the PC is always the main panel. A sub panel can feed the main panel (or a portion of it) while distributing the isolated neutral and isolated grounds back to the Main panel bus bars along with the hot wires to circuit breakers. Just because the sub panel is back feeding power to the main panel does not mean the sub panel is now the main panel….
Each circuit on the transfer switch has 2 wires going into the main panel, a red and black. The red connects to the breaker you want to power. The black that was on the breaker is connected to the black from the t-switch. So power comes into main, goes to T-switch, then comes back into panel and out to the circuit in the house.
There is a neutral and ground from the T-switch L14 plug that is connected to the neutral and ground bars, respectively, in the panel. These are a straight pass through from the generator.
The transfer switch was made by Gen/Tran, which is now called Reliance Controls, based in California. They were owned by Generac for a time, and they still make my switch, under the name Pro/Tran. It is UL listed.
I believe you are correct, if I remember you should only have your neutral and ground bonded at the first point of disconnect, that would be your transfer switch auto or manual. ALL other panels should be wired like a sub panel. I just had to separate my main panel and add a larger ground buss.
@@bayouslots3143 - I know I’m correct, as you yourself discovered the ground and neutrals are to be separated in a subpanel. What’s unclear in this particular picture is why there are people who think the breaker panel hasn’t become a subpanel …
Its not coincidence that the cord end that connects at the generator had the issue (while the other end lugs were still tight). The generator shakes, and over the years the screws backed out. I wouldn't assume that the cord was bad from the factory. Thanks for the PSA, I'll go check my lugs and maybe even add some loctite...
I agree about the vibration. 👍
Learn two things from this:
1 - Do a trail run before the power goes out.
2 - When you do the test, open all breakers. Make sure you get the proper voltage in the panel (or transfer switch) from both phase to phase and both phases to neutral.
Well, I guess this was a trial run. It literally happened in about 5 seconds. My understanding from what others have posted here is that both legs would be 120 until you start adding load. Unless the load is exactly the same (not likely), things will go south real fast.
Thanks for the story. Glad you figured it out, and glad no one was hurt. I'm sure it was a real head-scratcher.
Now... to finish the explanation. When the neutral was bonded to ground on the generator (as well as at the service panel), the ground wire provided a return path for the current despite the disconnected neutral wire. So everything worked, although not as designed. When you unbonded the neutral on the generator, the ground wire could no longer provide a return path to the generator's neutral. I don't pretend to know exactly what fried your surge protectors but obviously it created an overvoltage situation.
However, I think it would have been more appropriate and more helpful to title this video "Faulty Generator Cord Started a Fire!"
Thank you for the explanation. That is what I've been told as well. I know it will be nerve racking using the generator the next time I need it until I calm down.
Surge protectors are made to clamp voltage at a low enough level that your electronics aren't damaged by a very brief spike in voltage. But sustained over voltage causes the MOVs to get extremely hot. Plastic surge protector casings can melt or burn. Although the sustained over voltage situation is rare, I decided many years ago to get surge protectors with metal casings. I had seen an over voltage situation at work that melted a hole through the bottom of one of our surge protectors and burned the carpet it was laying on. Fortunately it was only the carpet directly under the hole and the rest of the carpet did not catch fire.
I remember when, as a heating contractor the first electronic controlled furnaces appeared. I was installing one and upon testing it wouldn't fire and shut off on safety. I fiddled with the thing for over an hour and finally got on the phone and called the manfactures engineering dept. The told me to check the polarity of the black and white wire coming. Come to find out the black was the neutral and the white was the hot leg (+). I wired them backwards and let the customer know in case of any future issues. Polarity has become quite critical. The grounding when using a genset is more than confusing to the average user and has been the cause of many a mishap.
Found that to be CRITICAL when using twinning control on two 120 volt furnaces running in combined mode.
Wild that a caboe you've been using without incident just suddenly isn't wired right. Circumstances changed and made a huge difference in this case.
Thank you for the lesson. About to install an interlock kit and buy some cables for a new generator. Will definitely be checking the connections all around.
Glad it was helpful!
Your description is a little confusing. What happens with a missing neutral is that the only path for current to flow is between the two hots. There is no ‘phasing’ issue going on. Basically what you had was unbalanced phases, ie the load on phase A was different than the load on phase B. All the current is flowing through all the loads on phase A and then flowing through all the loads on phase B. If they aren’t matched, then the 240V from the generator (voltage across the two phases) isn’t evenly split, so the voltage loads have on phase A might be say 180V and the voltage on loads on phase B is 60V
Think of hooking two mismatched lightbulbs in series, say a 40W and a 100W and connecting that to 240V. The 40W bulb would see a much higher voltage than 120V and would quickly burn out.
That’s why the problem got worse as you started switching more circuits in. Had you switched all circuits at once it’s likely the loads would have been relatively balanced and you wouldn’t have discovered this issue.
All that said, throw any of those surge protection bars in the garbage immediately. They are a faulty design in in that situation then starting burning. You NEED protection like that to be self fused, those are absolute junk, and frankly shouldn’t be permitted to be sold.
My electrical knowledge is limited to basic wiring. I described what happened as best I could, based on what I was told. I don't understand why those surge protectors reacted the way they did. I've been using APC products since the early 90s, they've always been considered a top brand. It's hard to know what to have confidence in for an average person, I think.
When I switch over to generator, I flip one circuit on each side of the switch, trying to keep the load equalized.
It was very scary, I'm glad it wasn't worse.
Thank you for posting!
Nothing faulty about the surge arrestors. They were used outside their designed criteria. With a broken neutral you get an imbalance in voltage, exactly as you described. But a surge arrestor can only absorb so much energy and normally with a connected neutral it would have tripped a breaker under a sustained over voltage condition or the surge is momentary. But in this case with no neutral and the current flowing through the arrestor due to a higher than normal voltage AND flowing through a device(s) on the other phase it limited the current to less than the breaker. So the arrestors were clamping and flowing current far longer than they would in a correctly working system. Even with your idea of a fuse, the current may not have been enough to blow whatever fuse you installed, since these were probably feed with a 15A branch circuit to begin with.
2:37 OH MAN those models LOVE to do that when “protecting its load.” I worked in IT at a community college a few years ago. We had a TON of these that looked exactly like this in one of our largest buildings(happened to be administration! Lol!), we had TONS of equipment and cameras go offline and not come back up. We were a little confused until we got into the office Monday morning after spring break to find that the utility replaced the pad mounted transformers and accidentally doubled the voltage somehow and so all of the 120v surge protectors burned up EXACTLY like the one seen here! 2:37 all of the computers that were plugged directly into the wall were fine because they could handle 220-240v. We ended up spending like $35,000~ I believe replacing all of the power strips and old crappy 120v power strip style APC battery backups from the same era. I’ll admit, they sure did their job! Albeit not in the most elegant way possible. 😅 The other surge strip models from APC & Eaton/Tripp Lite were perfectly fine so if you ask me APC made a bad product and refuses to do anything about it or admit it. They all burned up so badly I have NO CLUE HOW NONE OF THE FIRE ALARMS WENT OFF!!!
All of our Eaton battery backups were fine as they shut off their internal input breakers and remained on battery/off until the proper voltage was restored. Can’t say the same about that generation of APC battery backups though…
I am n IT Director and I use AOC all over the place 😮
The generator survived the experience? The people who say hire an electrician for everything must be rich. I do dyi because I'm not rich and when I've hired electricians for major projects they haven't impressed me. Thanks for the info.
The generator survived and appears to be unfazed. Its main breaker tripped about five seconds into the event. I've always been a DIY'er with pretty much everything - houses, cars, motorcycles. If I had to pay someone every time you needed something done I couldn't afford half of the things I own.
Nobody's perfect...not even certified professionals.
One of the greatest youtube videos I have watched!!!! Good for you for finding the root cause.
@@user-gq2vn1xj2r Thank you. It took me a couple weeks of researching and asking questions, I was determined to get to the root cause. Definitely scary stuff.
100% this was caused by a floating neutral. In Australia we use three phase and not split/2 phase like North America, however the outcome is the same. The most loaded phase goes low and the lightest loaded phase goes up to the phase to phase voltage of 415 for us. If my eyesight serves me correct, the smoking gun is the wire ends in the female lead socket, they were tinned with solder, and absolute no no! Copper has decent spring tension and will maintain a tight bond under a screw terminal, if the conductor strands are tinned with solder, the lead will slowly flow away from the pinch point with time and become lose. I have seen this more times than I care to remember and always go off my nut when I see people doing it.
I was next to a piece of equipment that lost its neutral some time back, it was like firing my 44 magnum without hearing protection, I traced the fault to a lose neutral that had indeed been solder tinned and worked lose with time.
Wow, that is crazy!!
Great info. Glad the family is safe.
Much appreciated, thank you!
Thank you for sharing your experience. By sharing this you may have helped others. Kudos to you sir!
That's what I hope for. Thanks for posting 👍
I had a small power strip that I found had the hot and neutral reversed (I was getting buzzing/noise in my 40" monitor plugged into it). I had used it for decades. I opened it and swapped the wires (and tested it... and all my other strips as well, with a tester like you have).
Wow, maybe replace that strip with a new one.
Having seen many pictures of surge protector strips that melted down, some resulting in a fire, I have decided that I will only buy surge protectors that are in a metal case! A good one is fairly expensive but a lot cheaper than the deductible on the insurance policy. Plastic outlet strips that do Not contain surge suppression don't worry me as long as I don't load them heavily.
that APC unit gave its life to try to protect what was plugged it to it. the problem is that all things have there limit. if that was all you lost you were very lucky. i have seen floating neutrals take out everything in a house including refer, washer, dryer, microwaves , TVs and more. the more load differential between L1 and L2 the worse it is.
I haven't found any other damaged items, which i'm super glad for. Very fortunate!!
Thanks! I’m going to check my cable tonight and my shore power cable also.
Yes, actually that's how surge protectors work. They short out the line when voltage goes to high. If the breaker does not shut off, it will just burn itself up.
A surge protector is just a device that has high resistance up until a certain voltage and then it drops resistance rapidly acting like a crowbar circuit (it shorts out supply).
It's a little $0.10 device called a varister that sort of looks like a fat ceramic capacitor with two legs and its just soldered onto the hot and neutral and in some strips another is soldered between hot and ground. The reason why is burned up is because it was unable to trip the breaker.
Nice explanation 👍
That is true but surge protectors also need over current protection to prevent what happened to OP.
@@tomschmidt381 Surge protectors dont always have current protection. Most don't. The switch on top is just a plain rocker switch with a little backlight.
If it has a circuit breaker it will be a little black pop out style on the side like what some appliances have. The average surge strip you buy at walmart has zero protection besides the ability to short out when overvoltage occurs. So if you have a surge, the strip shorts out to clamp the voltage and will continue to do so until the circuit breaker in your house trips. If that does not happen, then the strip just self destructs.
Great video, well done. I too have unbonded my gen but have never had the need to run any length of time other than the initial test a few years ago.
@@robglennie9526 Thanks so much. Probably good to do a test at least once a year. Be safe!
Excellent video. You can never be too careful. Great job. Some would have left the other video live and done nothing. You immediately took it down when you had a problem and then had the thoughtfulness of other people to talk about it and walk us through your solution. Bravo and Thanks.
Second comment. I wired my own cable but haven’t been unlucky enough to have to use it yet. Going to check behind myself now. Thanks again
@@mindsablank8061Thanks for the comments !
Agree. Nice video @bluesriderDf. I'm an EE (PE) and this is one of the best plain-english explanations I've seen on this topic.
I'm also glad the old video went back up, as it was very helpful too.
When you drop the neutral the loads on one phase are put in series with the loads on the other phase. If they aren’t balanced evenly you will get a high voltage on one phase and a lower voltage on the other. Think 240 across 2 different value resistors in series. The higher resistor will have a higher voltage drop than the lower. Same current through both.
Would a whole house surge protector have helped in my situation? I'm thinking probably not.
@@bluesriderDFprobably not, they need the nuetral to do any work.
@@bluesriderDFit absolutely would have
I have an interlock on my main panel. The generator I use is a Honda EU7000 that has a Floating neutral from the factory. The Honda EU and EM series generators have floating neutrals. The EM series have bonded neutrals.
thank you.. this is a must watch video if you own or plan to own a portable generator
Thanks for posting!
This is a good reason to buy a molded cable, not one that has hand installed plugs on each end.
@@deltabravo1257 I wholeheartedly agree 🖕
In order of electrical contact quality you have:
1- soldered.
2- machine crimped.
3- spring loaded.
4- hand tightened.
5- hand crimped. with proper tool.
6- hand crimped with non specialized tool.
If you can yank the wire off the terminal with a good tug, the connector fails. Regardless of how it's made.
Earthing and diverted neutrals is also becoming an issue here in the UK for 'similar' (though not exactly the same) reasons.
There's a lot of discussion about earth disconnects for EV vehicle chargers where (here in UK) there can be lots of other electrical services near the point of charging that end up (especially under latent fault conditions) with different 'local earth' potentials which is cross bonded produce large unexpected currents (the latent fault becomes potentially patent/obvious!).
Obviously if there is a local 'fault' causing your outage, you can have a similar unbalanced earth issues.
(edit: e.g. have a look at `e5 group`s webinars on diverted neutrals)
Power bars like the one in the video use a simple device known as an MOV (metal oxide varistor) connected between line and neutral, which does nothing until the voltage spikes above a certain threshold at which point it becomes a dead short. This short then trips the circuit breaker in the power bar. Many of these breakers are not very effective against dead shorts and weld themselves closed. If you are lucky the house breaker will then trip. There is a large selection of surge protectors out there, Choose them carefully, there are a lot of cheap imports around. I personally use computer grade UPC's for all my electronic gear.
Nice explanation, thank you!
Wow! Had sort of a similar-ish thing happen nearby lightning we suspect wasn't home at the time came home to find most of our power strips zapped. Yeah supposedly they wear out overtime that's why you need the ones with the Protection LED assuming they're not just straight wired in. Ended up losing the power adapter for a TV converter box and not the CRT TV the cheap CRT TV! And about a dozen power strips. I salvaged the cords they were still good. I went through every power strip that I can opened and checked the inside. I have just started getting in the habit of anything that is Electrical is inspected before use after purchase. I picked up a inverter and discovered that they didn't slap the circuit board in properly so it was warped.
Thank you for this video. Just a follow up question: Even though the right thing to do with your setup was to float the neutral, do you think the fire would have still happened (regarding the cord problem) if the generator would have had the neutral bonded?
The neutral had been bonded to ground and I was using that setup without a problem. Little did I know that the ground wire was essentially acting as the neutral until I remove that bond, and then the crap hit the fan. 😱
thank you
Thanks for bringing awareness!! Will definitely be inspecting all cables as I am currently installing a transfer switch and generator inlet at my house.
This is exactly why I posted it. Thank you!
You are correct in unbonding the Generator frame. Loose coonections are the true cause of Electrical fires. You should check the terminal screws on your outlets and switches, my expectation is that many will take a 90-120 degree turn , if your home is more than 15-20 years old.
Well I never thought of that. Excellent, idea and I will be doing it.
I put new outlets and switches in my house. Didn't find any loose switches or receptacles but did find a couple that were so poorly stripped the wires were almost cut through and broke off as soon as I pulled the switch from the box. I tightened connections at the panel and found that all the connections on the side of the panel closest to the garage door were 1/4 to 1/2 turn loose. I suspect the greater temperature fluctuation near the door caused the connections to work loose over the few decades since the house was built.
Good video here. I'm going to buy a cable like that and will check the connections before use.
Thank you! Glad it was helpful.
Thanks for this video. It definitely made me go "Huh." I think I'm going to check all my connections now.. 😊
lost neutral. and ck cords cause they do discolor oxidize. very good and scary video. great job thankyou
Thank you sir 👍
Marvelous video! Thank you. I assume your generator is still not bonded to ground?
Thank you so much! When I was running the generator at the end of the video it was in floating neutral configuration. That's how I plan to run it going forward.
Something you might want to consider if buying a 12" square ceramic floor tile to go under your power strips. The MOVs can wear out and short. A good strip should detect that and open the power. But better safe than sorry.
I was thinking about this also. Thanks for the tip.
OK... Let me break this down for you. If the neutral is switched in your transfer switch, then you must keep the bonding jumper in the generator, because then it is considered a separately derived system. This main bonding jumper bonds the neutral bus to the ground bus and frame. However, if the neutral is not switched in the transfer switch, then you need to remove the jumper from the neutral bus to the grounding bus in the generator. The ground bus should still bonded to the frame, but not the neutral. In a nutshell, the 'main bonding jumper' should only exist in one place, and that is at the point of service. The way to tell if your transfer switch has a switched neutral is by the poles; most residential houses have a single phase two pole 240V service. If your transfer switch is two poles then it likely has a solid unswitched neutral aka (SN kit), but if it is three poles then it is a switched neutral. If you are just not sure what you have, then leave all the bonding jumpers in, it won't meet the code but it is much safer than removing the main bonding jumper when you need it.
Thanks Stormy. The transfer switch just passes the neutral from the generator straight through to my panel, it is not switched. I have removed the bonding jumper from the generator. I have confirmed with a meter that the neutral and ground at the generator are not bonded. When I plug in the 30 amp cable to the transfer switch and generator, the meter shows the bond is back.
The thing is, I have read so many horror stories here of what loose neutrals can do that I almost wonder if it would be better to just bond the generator, even though it's not code compliant.
In my head, I know that's not the right thing to do, but living through this was not pleasant.
@@bluesriderDF It does not meet code but half the generators I service are bonded and on and an unswitched neutral. I have never seen any of them with an issue because of it.
That is the problem with MOV surge protectors in a plastic case. They are inherently dangerous, and will catch fire upon loss of neutral or prolonged over voltage. Burning plastic can quickly set fire to anything nearby. It is safer to get a plain old power strip that does not have surge suppression. The NEC now requires whole house surge suppression, so those point of use units are redundant anyway.
Good points. I installed a whole house surge device after this fiasco happened.