Delta connected secondary service (customer connections) are no longer offered by most utilities. Some remain in large industrial systems, but are no longer installed. Three phase 120/208 volt distribution is what’s normally provided to apartment buildings, hotels, and businesses. Larger industrial customers , high rise office buildings etc have 277/480 volt service and have step down transformers to produce 120/208 volt. Most low voltage three phase motors are rated 208-230/460 meaning they can run on 208 volts, 240 volts or 480 volts. Single phase motors are generally rated 200-230 volts so operation on either 208 volts or 240 volts is acceptable.
We also, in this canadian province don't use 277/480 that much. Almost always 347/600, or 120/208 . Seen some 277/480 in a few older 60s buildings. But very rare still here. No deltas either..since the 50s probably.
Being a non electrician it was a little confusing however I've always wondered where these numbers came from. This was an excellent topic to cover. I did learn a lot from it. Saving this video for future reference. Thanks for taking all your personal time to educate us, truly appreciated.
The main thing is you have a crap electrical system in the USA and had it been designed properly from the outset you wouldn't need all these different voltages. You only need one voltage, one voltage on the income supply. That's the phase voltage. A single voltage. Then by virtue of the fact you could supply multiple phases at that voltage, you then end up with a second voltage which is the line voltage which is higher. That's all you need is a single supply voltage. But you haven't got that. You've got over 50 different types of receptacles and matching plugs to handle all the different voltages and current ratings. It's a complete and utter mess. Overly complex for no good reason or benefit. And no one in the government over the decades has had the balls to sort it out.
Great channel. Practical bits - well explained - very clear. I wish more of us (engineers) had the practical sense of electronics. There's not enough mixing of the theoretical people with the practical get-it-done people these days. That mixing would benefit both groups.
You get a lot of practical and theoretical in construction. It just happens after the contracts are signed. What I don’t get is, somehow someway, the engineer of record is never wrong. 😂
One way of avoiding frying your appliances or motors is to check the voltage using your multimeter before you hardwire in or plug in your new device. Absolutely great video though.
I used to be an aircraft electrician in the Navy. Now I'm a Locomotive electrician. Locomotives generate 1200 volts (dc) at 2400 amps (for 4400 hp). Paranoia is a healthy thing I always tell the Noobs...
Good points. It's not the bolts that kill you. It's the Amps. A Static discharge that shocks a person in their home, can be 100,000 volts. Luckily, it's very low amps. One half of an amp can kill.
OMG. In 14 minutes, You have explained what I had to learn on my own 50 years ago. It took me a whole lot longer than 14 minutes. And there was no such thing as 5v and 12v lighting controls, etc. Thank You !!
@@bruceb3786 actually, there is 12v lighting controls and systems. some smaller lights use 12vac (under-counter lights, garden lights, some track lights). it is rare to see 5vac but there can be 8vac for older doorbells
PLC CONTROLS ARE 12 V. & 24 V.and Fiberoptic here where I work AND MOST FIELD DEVICES ARE 120 ALL MOTORS WE GOT ARE 480V. AND SOME 4160 VOLTS , BUT PLC'S ARE 12 V. & 24 V. An Fiberoptic from control room to mcc where PLC CONTROLS are located .
I have seen a 762 volt system in an oilfield before. Phase to neutral was 480 but line to line was 762. This was a rare system that I am sure is obsolete by now.....Great video by the way!
I'm in high school and been watching your videos and they are excellent. They have gotten me interested in becoming an electrician. Do you think you could do a video about switchboards or switchgear. What they are for, all the different components on them and what they do, and showing us one in real life. I've seen them whenever I pass by some buildings but I don't know anything about them. Thanks! Keep up the great work.
Thanks for taking the time to reply. When I applied for an apprenticeship (in 1967) you needed a sponsor, or relative in the business. Unfortunately I didn't qualify. Now they are begging for young people to become apprentices. So sad the school counselors for many decades have discouraged students from going into the skilled trades. There is a tremendous shortage of skilled labor today for this very reason. It is an honorable profession and everyone in the business should be proud to be involved.
Good point i look on the bright side. Less competition. Not that, the field isnt competitive in several aspects.. but it should make it easier for us young bucks to get in and that should make us feel way more excited about the future in the trades. Thank you
48V is also a common low voltage in the IT world as it's the voltage used for PoE equipment. Good explanation on how the voltages are derived. Was hoping for a bit more of a history lesson as to why the various service voltages and configurations were chosen and have fallen out of favor.
Great job Dustin !!! My first experience with 277 was with a metal fish tape into a florescent light fixture., doubled over as the current went across my chest. #@%^&I* it hurt like HELL !!!
Mine was also a fluorescent light fixture. One of those "designer" ones hidden in a little alcove. Push in connector attached to the ballast disconnect plug came out and touched me, that was nicely grounded to the fixture chassis. Lit me up real good. arm hurt for a couple days for sure. thankfully didn't fall off the ladder because my buddy was holding it for me. Was comfortable with doing light fixture repairs hot before but, won't do that style again if it's 277
Dustin... I've been an electrician for just about 20yrs and I'm glad to learn something new or be reminded of how things works. I've watched several of your videos and have certainly learned things. Anyone who tells me that I should know everything about the trade as a master electrician is just ignorant. Yes I'm a master electrician but I literally only get involved with low voltage work when I do side work. There's lots of things that I've simply never worked on or seen. That's how I found ur channel... Looking up something I was troubleshooting that I had never worked. I work on the utility side now and have since learned that under 2,400 volts is considered low voltage, medium voltage is 2,400v to 69,000v, and high voltage is anything above that (transmission). For years I referred to 50v or less as low voltage, 120/240 as medium, and 277/480 - 600v as high voltage. I've never worked with 600v systems and I never knew that there was such a thing as 347/600v. I appreciate your knowledge and explanations and refer people to ur channel including my own son who has started in the trade. Thanks.
Awesome bro, I’m a maintenance technician who does a lot of electrical related stuff; whether it be lighting repairs, or new installations, or repairs and replacements on motors and machinery. I went to a vocational school to learn electrical and it’s cool to be be able to come to your vids and be able to refresh a bit
i like that you showed the corner grounded delta because it is a situation where a phase conductor can be a grounded conductor without being a "neutral"
Brad Lanier the grounded conductor is only a kludge to equalize manufacturing inequalities due to age or manufacturing mismatches in the coil windings and/or power delivery errors. In situations of utopian perfection, the potential would already be neutral or at least no current would flow through the grounded conductor.
The Canadian medium voltage standard of 600/347V is becoming more and more popular in U.S. industrial facilities instead of 480/277V as it saves 20% of the wiring cost.
There were times that even you looked confused trying to explain A good thing that the UK is much simpler The consumer side of the transformer it star, doesn't matter what application L-N is 240V, L-L is 415, yep, it's that simple For a treet, they drop a live and neutral in rotation to each house, house 1 gets L1, house 2 gets L2, house 3 gets L3, house 4 gets L1 etc. 3 phase is generally only used in commercial properties, they only need one 3 phase supply, and can take single phase supplies from that 3 phase, usually splitting loads to keep the phases balanced (a large room may have 3 sets of lights, one on each phase) Motors can be wired as star or delta, or even use star/delta start/run Because we are all 240/415, our cables can be smaller, this saves on copper.
New to the electrical game watched most but not all your videos really enjoy the authenticity you bring wish more people would be teachers of the craft instead of worrying about what their gonna earn from it #toeachoneteachone
Ohhhhhh boy...you just can't leave out the earnings! What with the overtime, the weekends, the holidays! Time and a half, the double time, the TRIPLE time! The call outs, the storms, the wind-sheild TIME!! And everyone's pal: UNCLE SAM will be riding shotgun...for heavens, * DONT LEAVE OUT WHAT YOU'LL BE EARNING!! 😘😜🙄
Thank you for this video, I love this style content and how you explain things is fairly easy to understand. I’m almost into my second year in the apprenticeship and you have explained so much about transformers and systems that I haven’t understood for my previous time. Thanks man, I really appreciate this video.
In Serbia we use standard EU system. It is actually German standard and it is very neat and reliable. Street transformer is always in wye configuration. Central point is grounded and that is neutral comming from transformer. Between phases you get 400-420V, and between neutral and each phase 230-240v. It is safe. Nobody here is electrocuted, and every household has 3 phase system. It is very practic especially who has a workshop or other business requiring strong motors for woodcutting, or other appliences including electric heating that is allowed to consume 24kW of power per house. Every pole transformer here is rated for 250KVA, 400KVA, 630KVA and 1000KVA. I havent seen stronger than 1000. Great video, keep on going!
@Walkr why? There's multiple different types of electricians most residential and even most commercial electricians don't know anything about industrial. And vice-versa. Also we're in a new era of people who think because they do some electrical work they're a electrician and they don't even know how to use a code book and thats the problem.
Now I am glad tho be an electrician in Europe where we have 230V(/400V) system everywhere. Small houses and huge industrial companies run on the same system
Some countries still have 230V three phase system. In France it's almost extinct, only found in some old factories with private transformer, but in Belgium and maybe other countries both 230 and 400V systems still coexists. Depending on the cities or the street you can have 1 or the 2 systems. I was told it's a real pain in the ass for music festivals or concerts tours. Electricians often have to rewire the panels depending on the voltage
@@lionnelc13 Norway have a lot of 230V IT/TT (Delta configuration) , but greenfield construction is with 400V TN (Y configuration). A lot of old houses or small apartment only have one of the phases into the building, so unless you have a Renault Zoe, you won't notice it.
@ Simon Schertler yes, i'm glad that i'm an electrician in Germany with the 230V (/ 400V) system. only the plugs schould be the same across europe (the world. i think, the poland has the best plug: germen plug whit a ground pin).
In Amsterdam are parts with the old system with 2 fases, each 127 VAC. Making the 220 VAC between those fases. 127 x sqr(3) = 220 VAC Now many countries in europe have 230 VAC and maby in the future 240 VAC. More voltage, so we can deliver more power through the same wires. The current determents the wire gauge, so to get more power (P=UxI) we're getting higher voltages. Same for the higher voltages, 380 VAC come from 220 x sqr(3) and the newer 400 VAC comes from 230 x sqr(3).
It’s called trigonometry. If you draw a dashed line from the top of your delta transformer to the center of the base where you tapped the ground, then you just made two right triangles. You know both sides a can use trig to find the base.
Ultra low voltage - 50 volts and below, low voltage - 50 to 240 so typically 120/208/240 volt systems. Medium voltage is 277 to 600 volts. High voltage is anything above 600 volts. That's just how I differentiate it I know this an old video but I figured I'd put it out there anyway. Then there is data systems, internet Telcom all that and well we just shit talk the data guys cuz why not. Nah I'm playing got a buddy who does internet and security systems he's great but nothing of his blows up, shorts out, arcs or sparks and what's the fun in that.
a wye transformer allows you to transmit high voltages with very little current, whereas the delta virtually does the opposite [allows high current]. such is why transmission lines ie high voltage use wye transformers. typical uses for delta transformers are for industrial uses, but again, they themselves are fed with wye transmission lines. Some deltas have a grounded lead in which they most definately require a ground fault detector/protection. the possibilities are numerous ie wye-delta, wye-wye, delta-wye, delta-delta. each transformer has their own uses, step up, step down, isolation etc.
because i couldn't/wasnt able to adequately explain myself...please check out this guys vids for some relatively easy understanding[easy for me anyways] of what i'd already learned going through my 3 levels[in-school learning] as an apprentice. ua-cam.com/video/rEiukQLCVao/v-deo.html the way "you" explained deriving something like 120/208 or 277/480 is "almost" factually wrong. i say almost because while it could be done your way, and in a few industrial settings it is, that is not how anyone ought to be doing it nowadays[safety reasons etc]. if you want one service and two different 'systems' of voltages, you'd keep your wye sourced power as your main and feed a secondary wye-delta transformer if you need high current and different voltage from your standard 120/208y main service.
K Hills bro, what are you rambling on about? Nothing he said in the video was incorrect. He wasn’t telling anyone how to “do” something. He was just explaining how the voltage numbers work out for different types of transformers.
i didnt want to bring it up, but "you" brought it out, ..: i understand what he's talking about and trying to explain. but he couldnt have done it any worse than you calling out that "he" didnt do anything wrong. your obviously not versed or couldnt be, in the the electric arts lol..[sry for the pun]. i would not have shown or taught voltages "that" way[his way] because i know better and have a better understanding. when i said i didnt want to bring this up, i meant this guy teaching it er..."elec u" etc doesnt have a very good understanding of how shit works. ie transformers. i wasnt trying to literally call him out, but i did leave a link to a guy's vid who knows fuck more than this guy.
lmao, sry, im being a bitcx. my grief is not with you, its with elec u. ive done calculations and such way back when and i remember my lectures etc when i was doing my level 2 and 3, and it annoys the hell out of me when i see :yes this could work; but it is almost never done and i could think and draw diagrams to more easily explain this crap. mostly because i dont want people thinking they can just "tap-off" a 3 phase delta transformer no problem...lmfao!!
You have no idea what you are talking about. I am an electrical engineer. I design systems using a delta-delta and delt-wye every day. Why in the hell do you think a wye transformer allows you to transmit high voltages with very little current, but a delta doesn't? Have you ever taken an engineering power systems course? You are COMPLETELY wrong when you said, "a wye transformer allows you to transmit high voltages with very little current, whereas the delta virtually does the opposite [allows high current]. such is why transmission lines ie high voltage use wye transformers." Where in the hell did you learn this? Did you create this in your head or did some other dumb-ass tell you this?
With the 3 phase 4 wire delta system, the NEC requires you to write or put a warning label on the panel in question " Caution, B phase is 208 volts to neutral.".
If I have a three prong twist outlet that is 208 is there any way to use that for an appliance rated for 240 like a dryer or oven? (I’ve got no 240 outlets in my building). Or do I need to run a new 240 line from the breaker to run 240 appliances
I am wiring a 230volt three phase hydraulic pump from a Lincoln welder/Generator three phase Delta 240volt. My question is do I just run the three hots or do I also wire the neutral to the pump. Thank you I would really appreciate your answer.
3 phase 240 is a delta low side, your not going to see it much at least in my area. They do it so they can center tap one side and get you 120v single phase. Most low voltage three phase you will see will be 208v, which is a wye configured transformer.
@@josephkordinak1591 thank you. I'm in the business of installing battery chargers and have ran into 240 3ph once in the last year but 208 a handful of times. Thank you for the explanation
In 1947 thru 1985 their was low voltage controlled lights in some more expensive Houses ...28.5 volts energized from a transverter to a relay that would turn the light on with 120 volt
he could have just described it as vector math and leave it at that. for someone that might not know, it might have helped. other than that, very good description
I ran across a high leg on a residential service upgrade. It was confusing because it was a house 🤔. Here I come to find back in the day it used to be a shoe repair shop with living quarters upstairs for the shopkeeper 😂. They actually ran 3 phase into neighborhoods for these small mom and pop shops! There were 2 separate services, single phase for the upstairs and 3 phase for the shop. And it was all still fuses! It was pretty scary looking actually 😂Luckily I checked the voltages before I hooked the service up LOL.
If u see a panel with every 3rd breaker available. Good chance that’s ur high legs. Double check ur voltage Not spare 120 All this 3phase stuff makes sense if u understand physics. And vectors
Btw my journeyman taught me all of these calculations a while ago and I thought I had a decent understanding of it but once you explained I feel like I get it way better now. Appreciate you Dustin.
Poe = 24v dc and Poe+ = 48v dc it’s to power cameras and switches. It’s considered low voltage since it doesn’t move a lot of current. All this power runs across an ethernet cable.
Most 3ph motors in the factory I worked at were 550. Had one wacky machine that had , I think, 308v motors. Machine had its own transformer in the control cabinet.
So I get how on a 3 ph 4 wire 480v wye you get 277 to neutral on all phases. How about a 4 wire 480v delta? Will there be a high leg and if so what voltage?
I am a seasoned electrician of 34 yrs and I enjoy how Dustin puts things in layman’s terms which is a gift and not easy to do! He did however forget to mention if your not a licensed electrician to stay away from higher voltages like 208, 277 and 480 volts. They all can kill you quite easily. Especially 480! Nasty! Don’t play around please if you aren’t a professional...keep up the great work Dustin!
How do I connect a breaker for a Ac on three face panel ? How do I pick the 120 volts leg ? Because one leg is 120 y the other one is 208 volts :/ I know how to do on a 2 face panel , but in three face I’m confused 😬
c31979839 typically 347 is now used in underground parking lighting, luckily now lighting is 120v supply w 0-10v dimming systems which makes it a lot safer
@@Nick-bh1fy 347 volts is naturally a byproduct of the 600 volt Wye or star system. One almost only uses it out of convenience. There are times when you might have a 347 volt source nearby. And you would have to all the way on the other side of the building to find a suitable 120 volt source. It is typically used for industrial and commercial lighting in Canada.
As an electrician I commonly wire motors 120 , 230, 240, 277, 300, 480, 600, 1200, 1460 and up. Some are 200 amps some are as much as 5000 amps. I wire and manage transformers that step up or step down in the ranges mentioned above as well as voltages of 5kv,11kv,22kv, 33kv, 45kv, 120kv .... Low voltage Intermediate voltage HIGH VOLTAGE .
Love the content, this video was good can you do a demonstration with wire colors and physical materials , would love to see this broken down barney style, thanks
We bought an eco smart 27 electric tankless hot water heater. It takes three different 8 gauge wires with three 40amp 220v breakers We are thinking about taking it back because I have been told it will dim the lights when it comes on. Is there anyway to fix that? Awesome video, thank you.
You'd have to come out of the panel to feed a step-down transformer, 480-240V works fine since 240V draws slightly lower current for a given power draw. In this case you'd likely wire the secondary as a delta. You could also use three 480-120V transformers and configure a 277/480V to 120/208V set-up for the charger.
The 208 high leg is engraved in my mind now. Few months back i was landing wires for 120v plug inside generator enclosure. Picked the first unused 20 amp breaker i came across, might have been in a hurry. Sent 208v and cooked a $600 battery maintainer. I’ll never forget again. On a different note can you do some videos on why you would use dc versus ac in some applications like motors, controls, etc? Love the videos man your a great teacher!
All right I have a guy that bought a 208 V Brewing System but the power coming in is 120 240 single phase is his Brewing System going to work? I feel like even if it does work though it's probably not going to be good are the $30,000 piece of equipment
You might want to contact the manufacturer and make sure the 208V brewer is acceptable on 240V. A 208V rated heating element connected to 240V will run hotter than designed and although it probably won't burn out right away it will shorten the life and void any warranty. You could use a autotransformer to lower the 240V down to 208 and that's a common application for autotransformer, aka buck-boost transformer. Hope this helps.
In philly we had a "two phase" system fora long time. There are still some two phase buildings around. to supply them from a three phase supply you use a transformer connection called a "Scott- T". You can also cheat a bit and run two phase motors off of the delta with the center tapped winding and getting 240/208 two phase. The phases on two phase are 90 degrees away from each other
@@kennethdunklin278 The two-phase transformers weren't delta or wye. The phases were at 90 degrees and not 120 degrees. They were more like X or T connected. I know it's all strange unless you worked on the old Philadelphia systems and buildings. It was really a crappy system that Philadelphia adopted in the beginning of utility power and we were stuck with it for like 50 years or more. "In the early days of electrical engineering, it was easier to analyze and design two-phase systems where the phases were completely separated.[4] It was not until the invention of the method of symmetrical components in 1918 that polyphase power systems had a convenient mathematical tool for describing unbalanced load cases." en.wikipedia.org/wiki/Two-phase_electric_power upload.wikimedia.org/wikipedia/commons/thumb/a/af/Scott-T.JPG/400px-Scott-T.JPG I'm also pretty sure it's covered well in "American Electrician's Handbook" www.amazon.com/American-Electricians-Handbook-Sixteenth-ebook/dp/B00COKLSVO and in "Electrical Machines Drives and Power Systems" www.alibris.com/search/books/isbn/9780130824608?qwork=1985923
@@cindytepper8878 Do you know if loads were separated like power and lighting to balance loads or more like just stab them in and turn em on? Im sure like now days unbalance loads need a return but we havent always been on a grounded system. Early days I was taught used to be ungrounded.
@@cindytepper8878 Ok it is a different system than open bank and I see how they get the 90 degrees too. Literally a "T" thats cool. I could see it being assumed as a Wye or Star but its definitely not. Hell yea, thank you for sharing this.
@@kennethdunklin278 Here is one of the crazy transformer connections that was most common in Philly. It was 5 wire, 4 hots and a grounded neutral qph.fs.quoracdn.net/main-qimg-061bc48b1f8cece814845f7359c0f25a It was highly inefficient in it's use of conductor material. I'm having a hard time remembering how you got the load balanced on the primary 3 phase supply side of the transformer. It's been a long time since I've been involved in any 2 phase systems. I think the last one was an emergency generator for the Philly Youth Study Center (kid prison) and I remembering it being a nightmare. That had to be at least 20 years ago. I'm trying to remember the details
Bought a heater 2YU37 (rated at 277V 1ph) -- but I need to run it on 240V 1ph. Thinking the heating elements will just be less efficient and the motor will only run a freckle slower. Am I missing something? Getting a you can't do it, from many others.
You should check with the manufacturer to see if that's acceptable. It probably won't hurt, the biggest concern being the motor. A heating element rated at 277 volts but operating on 240 volts will produce less than rated output. Bear in mind, the NEC requires you to install equipment in accordance with manufacturer's guidelines.
Certainly well taught, kinda wish i saw some sinwave goin on to explain why the sqrt3 occurs, and thus also have the wild lag... Buh regardless of that i'm glad the white board came out. Being Canadian i defiently know 120/240 120/208 347/600 but what do y'all in the states typically come across, is 600v a thing there?
Not sure if it’s important or useful but when you plug 120 and 208 into the pythagorean theorem you get roughly 240. Curious as to why it doesn’t work for 480/277/240. Any insight?
If you're referring to the 240/480v 4 wire delta the high leg is about 415V, or 240*1.732 =415.68. The same formula applies to the much more common 120/240V 4 wire delta, high leg voltage = 120*1.732 = 207.84, or 208V.
I think I would have added that most 5 volt and 12 volt services are usually DC, but there are some low-voltage stuff that is just stepped down AC, for example, most residential HVAC thermostat controls are 24 volt AC.
It’s simple. On that system, every third position on the buss bar will be 208V to neutral/ground. The rest will be 120V to neutral/ground. Just use your multi-meter if you’re not sure. High leg is for equipment that requires or can use 208V.
The high leg is supposed to be the red phase (B phase in USA and A phase in Canada - don't worry.) And, you are only allowed to use it in a three pole or two pole breaker, and never with a single pole breaker. There is a lot more math behind it, much more than a text comment with a sale to explain. (Look up open delta on Wikipedia and that my explain more, though I've not actually looked there for this info, as I learned this in my apprenticeship school.)
Good stuff, as an instructor you make it easier to understand. I looked through your uploads and did not see any on 240v. I am specifically interested in ; add a 240 to a sub panel for welder, the difference in wiring to sub vs main panel, why the white/ common is not used, and what happens if it is wired to the wrong buss... I have a couple of electrician books and have asked a few folks that supposedly are certified, but have gotten a little conflicting information and now I am majorly curious...
Good Job explaining. As an electrician most of this was just taught and taken as fact. It wasn’t until much later at a Russell Electric School that the odd voltages were actually explained. In single phase the two legs are 180 degrees apart (sign wave) three phase are actually 120 degrees apart so the differential between legs will never be the sum of the different legs to neutral since one leg reaches the top of the voltage curve while either of the other legs at that instant has less potential related to neutral. That explains where we get 208 v 277 on 480 Volt systems and 2400 on 4160 volt systems.
I run into the center ground delta all the time in my area (northern PA) I work in a lot of hospitals, schools, and restaurants where we have to be aware of that wild leg but I have never seen it marked even though it really should be. Also I love your channel, I am HVAC/R tech and due to my job (I fix restaurant equipment and HVAC) I find myself needed to know a lot more about electrical than your average HVAC tech and your channel has helped a lot.
@@jaythompson5102 All over telecommunications I believe. Power over Ethernet being where most people see it, but anything in a telecom rack has a good chance of running off it. Someone correct me if I'm wrong, I used to work at the phone company, but I wrangled bits, not amps.
Yes, telecommunication systems typically run on -48v to -52 dc. If you take a dc voltmeter and measure between the two wires on a land line coming from the phone company, you should see -52v dc.
If you have 2O8 volts, you have 3 phase in the house. Normally don't see that on household current. 3 phase what I remember to ground is, one will have a higher voltage leg as the other 2 are about the same. I hooked up a 220 volt max car lift to 240 volts and felt uncomfortable about it for a shop. The shop owner sweared who sold him this uses 240 volts on them all the time with no problems.
What you are thinking of, is a high leg delta, common in rural area and usually seen only in older commercial buildings, but may also be found in newer construction as well, so always verify voltages before hooking stuff up. 120/208V wye is most common today, because each phase to neutral is 120V, and thus makes it much easier to balance the system when there's a variety of single phase and three phase equipment in use 120/208V single phase is actually very common in apartments, townhouses, condos and hotels. In these buildings, each individual unit gets fed two out of the three phases along with a neutral and ground, while the elevator and main HVAC systems run off of 208 three phase. In very rare cases, three phase can be found at a single family dwelling. Some utility companies will not install a single phase service larger than a certain size, such as 400 to 600 amps, and this might be the case for very large, custom built luxury homes.
Dustin, how does an industrial facility that gets supplied three phase 480 make 120v for standard lighting, 20 amp outlets, etc.? Do you guys set up a transformer similar to what would be on a residential pole to center tap one of the phases?
Yes, take a shopping mall for example. Most likely they will bring in 277/480Y 3ø. The 480V is used to power the elevators, escalators, and HVAC systems. The lighting will probably be 277V (if you look closely on LED drivers, or electronic fluorescent ballasts, you will probably see 120-277V markings, that's why) This is a very efficient lighting system because voltage drop will be minimal, and it's easier to balance the loads on the phases. There will be transformers in different areas of the mall for stepping 480V to 120V, or 480 to 120/240 to provide the 120V loads,
I know that these videos take a lot of time and effort on your end Dustin, but being an apprentice,these videos you do help a lot understanding electrical. Thank you for taking the time to put these together! It would be awesome if you can do a voltage drop video and understand the NEC and like ampacity and things like that.
Don't forget the stinger leg on a Grounded Center Delta, you'll get 208V to ground. That's how control circuits in equipment gets damaged if not careful
Fortunately these services are less common today than they were 50 years ago, and some utility companies no longer install 120/240 3 phase 4 wire delta in a new installation; the utility will provide you a 120/208Y system instead. Nonetheless it's critical to check the voltages with a suitable meter to avoid costly mistakes.
For those interested, the main reason power companies supply a 3 phase with 208 volt high leg is because they can bring good quality 3 phase power to a remote location(e.g. farm) using only two high voltage phases called V phase. Saves a LOT of money. As rural areas build up with new construction,both residential subdivisions and industry, it becomes more economically feasible for the power company to supply full three phase power. For that reason High Leg installations are slowly disappearing across the country but many still exist, so be careful out there.
If you draw two 120V lines in two phase (180 degrees from each other), then visually measure peak to peak it will equal 240V. I think if you draw out a three phase (120 degrees) and visually measure across the peaks the most you can get is 208V. It helps to see why it is 208V because the peaks of each phase never fully line up like two phase does. That's why you can't get the full 240V in a three phase. I didn't know about the square root of 3 trick to find that number quickly. Nice tip!
You can get the full 240V three phase in a deta configuration, and the best of both worlds (kind of) with a center tap on one of the transformers to give 120/240V single phase just like you'd find in your home, the winding furthest away from the center tap is the ghastly 208V stinger leg, you are not permitted to use the stinger leg to neutral for running single phase 208V loads.
Some power companies avoid a "wild leg" situation by only using the wye-delta bank for three phase. A separate (fourth) transformer is used to supply single phase.
I work in Utilities, we don't install a fourth transformer to provide a customer 3 phase and a single phase service. A bank with 3 transformers, we change the internal windings to achieve the desired voltages. For example, transformer 1 is (25KVA) in parallel, transformer 2 is in series (50KVA) and transformer 3 is in parallel (25KVA) giving the desired voltages of 120V/208V/240V. The size of the transformer for one is doubled to accommodate the additional single phase load.
It depends on where the neutral is dropped and if it's part of a multiwire branch circuit. A dropped neutral at a receptacle fed from a two wire circuit would read 0 volts. A dropped neutral at a main panel/sub panel/multiwire branch circuit would give a varying reading depending on the load balancing between L1 & L2 to neutral, could range from a few volts above or below normal to 240V on one line and 0V on the other because everything downstream of the dropped neutral is essentially in series with 240V.
Need some help! perhaps this would make for a good video. Installed 10/3 for dryer 30amp circuit and wires get very warm when machine in use. Receptacle gets very warm also. checked all connections and measurements are ok. The code calls for 10 gauge as a minimum. I’m not comfortable running the dryer when things are warm like that. Any advice anyone?
Interesting, In Australia/NZ and Europe, you're low voltage is regarded as ELV and SELV, everything above 80 is low voltage, with 1000+ is high voltage.
The high leg is so important to explain to apprentices and experienced electricians alike. I was completely unaware of it until one of the guys at my work described it to me when we were doing work in an old building. I am aware of at least one case where an apprentice turned professional overnight and decided to take on side work during his studies. He ruined a $3,000 commercial refrigerator running a dedicated receptacle feed and connecting it to the high leg.
Hi sir, Thanks for a great video. I would like to ask about 832Y/480. Why does the 832Y indicate? I saw this on an electrician test but couldn't understand what it stands for. Could you please help?
Thank you, I appreciate the time and the technical side of your explanation!! I hope more individuals your age continue to do well for all of us that are close to retiring! You are amazing!!
277 hurts a lot more
The fillings in my teeth still hurt when I think about touching the 277 volt lead for an emerg/exit light 40 years ago. I can still taste the metal.
I can't say it enough Dustin, but you are a great teacher. My former instructor could not explained this as clear as you did. Great job.
I wante work for you
Aba Kara I want to not work for you
I had an aunt faye. All her stuff was fays stuff.
@@abakara4859 no go find a job somewhere else
0
When in doubt, get your meter out!
JAMES! Since the 70's ... zippp...
Oh yeah! I even have an old analog Simpson like I learned on way back in the 80's. Lol
@@bowmanbk1 d'oh!
Yep more accurate than the finger test.
Couldn’t be said enough!!!!!
Delta connected secondary service (customer connections) are no longer offered by most utilities. Some remain in large industrial systems, but are no longer installed.
Three phase 120/208 volt distribution is what’s normally provided to apartment buildings, hotels, and businesses. Larger industrial customers , high rise office buildings etc have 277/480 volt service and have step down transformers to produce 120/208 volt.
Most low voltage three phase motors are rated 208-230/460 meaning they can run on 208 volts, 240 volts or 480 volts.
Single phase motors are generally rated 200-230 volts so operation on either 208 volts or 240 volts is acceptable.
We also, in this canadian province don't use 277/480 that much. Almost always 347/600, or 120/208 . Seen some 277/480 in a few older 60s buildings. But very rare still here.
No deltas either..since the 50s probably.
@@tripplefives1402 ✅ also allows more flexibility..
Not true in my area ...
@@tays8306 lots of delta in Canada. I have worked on many wye start delta run motors.
@@millwrightrick1
Depends on province. There is a few hanging around. But all the new installations we do are almost always 347/600v wye
Being a non electrician it was a little confusing however I've always wondered where these numbers came from. This was an excellent topic to cover. I did learn a lot from it. Saving this video for future reference. Thanks for taking all your personal time to educate us, truly appreciated.
The answer is phase angle, and it requires a lot more explanation than I can put in a YT comment lol.
The main thing is you have a crap electrical system in the USA and had it been designed properly from the outset you wouldn't need all these different voltages.
You only need one voltage, one voltage on the income supply.
That's the phase voltage. A single voltage. Then by virtue of the fact you could supply multiple phases at that voltage, you then end up with a second voltage which is the line voltage which is higher.
That's all you need is a single supply voltage. But you haven't got that.
You've got over 50 different types of receptacles and matching plugs to handle all the different voltages and current ratings. It's a complete and utter mess. Overly complex for no good reason or benefit.
And no one in the government over the decades has had the balls to sort it out.
Great channel. Practical bits - well explained - very clear. I wish more of us (engineers) had the practical sense of electronics. There's not enough mixing of the theoretical people with the practical get-it-done people these days. That mixing would benefit both groups.
You get a lot of practical and theoretical in construction. It just happens after the contracts are signed. What I don’t get is, somehow someway, the engineer of record is never wrong. 😂
One way of avoiding frying your appliances or motors is to check the voltage using your multimeter before you hardwire in or plug in your new device. Absolutely great video though.
I used to be an aircraft electrician in the Navy. Now I'm a Locomotive electrician. Locomotives generate 1200 volts (dc) at 2400 amps (for 4400 hp). Paranoia is a healthy thing I always tell the Noobs...
Screw the lightning strike, you should have powered the DeLorean with this!
dont be such a wuss. its only a few amps
@@eddiew2325 2400 hundred of them . How 'bout you touch it first, I'll go second...hahaha
@@eddiew2325 you'd get fried into a new dimention bud LOL
Good points. It's not the bolts that kill you. It's the Amps. A Static discharge that shocks a person in their home, can be 100,000 volts. Luckily, it's very low amps. One half of an amp can kill.
OMG. In 14 minutes, You have explained what I had to learn on my own 50 years ago. It took me a whole lot longer than 14 minutes. And there was no such thing as 5v and 12v lighting controls, etc. Thank You !!
Automotive lighting control is 12v...
@@No5elfCTRL , that's true, but 12 v auto wiring for lights is not normally used in residences, commercial, nor industrial projects.
@@bruceb3786 actually, there is 12v lighting controls and systems. some smaller lights use 12vac (under-counter lights, garden lights, some track lights). it is rare to see 5vac but there can be 8vac for older doorbells
PLC CONTROLS ARE 12 V. & 24 V.and Fiberoptic here where I work
AND MOST FIELD DEVICES ARE 120
ALL MOTORS WE GOT ARE 480V.
AND SOME 4160 VOLTS ,
BUT PLC'S ARE 12 V. & 24 V.
An Fiberoptic from control room to mcc where PLC CONTROLS are located .
you didn't have books 50 years ago?
I have seen a 762 volt system in an oilfield before. Phase to neutral was 480 but line to line was 762. This was a rare system that I am sure is obsolete by now.....Great video by the way!
I'm in high school and been watching your videos and they are excellent. They have gotten me interested in becoming an electrician.
Do you think you could do a video about switchboards or switchgear. What they are for, all the different components on them and what they do, and showing us one in real life. I've seen them whenever I pass by some buildings but I don't know anything about them. Thanks! Keep up the great work.
You might be interested in becoming a Lineman as well.
@@yolo_burrito Thank you very much, sir. Will do!
Definitely get ahold of your local IBEW if you wanna get in the trade.
Thanks for taking the time to reply. When I applied for an apprenticeship (in 1967) you needed a sponsor, or relative in the business. Unfortunately I didn't qualify. Now they are begging for young people to become apprentices. So sad the school counselors for many decades have discouraged students from going into the skilled trades. There is a tremendous shortage of skilled labor today for this very reason. It is an honorable profession and everyone in the business should be proud to be involved.
Good point i look on the bright side. Less competition. Not that, the field isnt competitive in several aspects.. but it should make it easier for us young bucks to get in and that should make us feel way more excited about the future in the trades. Thank you
You’re a natural born teacher. You explained the different voltages very clearly. Thank you!
48V is also a common low voltage in the IT world as it's the voltage used for PoE equipment.
Good explanation on how the voltages are derived. Was hoping for a bit more of a history lesson as to why the various service voltages and configurations were chosen and have fallen out of favor.
Makes sense. I always wondered how PoE stuff worked with such a low signal 😂
I know some Cisco stuff puts out 56v and with the voltage drop you get 48v at the end device.
Great job Dustin !!! My first experience with 277 was with a metal fish tape into a florescent light fixture., doubled over as the current went across my chest. #@%^&I* it hurt like HELL !!!
Mine was also a fluorescent light fixture. One of those "designer" ones hidden in a little alcove. Push in connector attached to the ballast disconnect plug came out and touched me, that was nicely grounded to the fixture chassis. Lit me up real good. arm hurt for a couple days for sure. thankfully didn't fall off the ladder because my buddy was holding it for me. Was comfortable with doing light fixture repairs hot before but, won't do that style again if it's 277
Dustin... I've been an electrician for just about 20yrs and I'm glad to learn something new or be reminded of how things works. I've watched several of your videos and have certainly learned things. Anyone who tells me that I should know everything about the trade as a master electrician is just ignorant. Yes I'm a master electrician but I literally only get involved with low voltage work when I do side work. There's lots of things that I've simply never worked on or seen. That's how I found ur channel... Looking up something I was troubleshooting that I had never worked. I work on the utility side now and have since learned that under 2,400 volts is considered low voltage, medium voltage is 2,400v to 69,000v, and high voltage is anything above that (transmission). For years I referred to 50v or less as low voltage, 120/240 as medium, and 277/480 - 600v as high voltage. I've never worked with 600v systems and I never knew that there was such a thing as 347/600v. I appreciate your knowledge and explanations and refer people to ur channel including my own son who has started in the trade. Thanks.
Justin, you are the best , I’m so glad I found your channel…
Awesome bro, I’m a maintenance technician who does a lot of electrical related stuff; whether it be lighting repairs, or new installations, or repairs and replacements on motors and machinery. I went to a vocational school to learn electrical and it’s cool to be be able to come to your vids and be able to refresh a bit
i like that you showed the corner grounded delta because it is a situation where a phase conductor can be a grounded conductor without being a "neutral"
Brad Lanier the grounded conductor is only a kludge to equalize manufacturing inequalities due to age or manufacturing mismatches in the coil windings and/or power delivery errors. In situations of utopian perfection, the potential would already be neutral or at least no current would flow through the grounded conductor.
Powerful lesson, I got a charge out of it.
I see watt you did there
The Canadian medium voltage standard of 600/347V is becoming more and more popular in U.S. industrial facilities instead of 480/277V as it saves 20% of the wiring cost.
There were times that even you looked confused trying to explain
A good thing that the UK is much simpler
The consumer side of the transformer it star, doesn't matter what application
L-N is 240V, L-L is 415, yep, it's that simple
For a treet, they drop a live and neutral in rotation to each house, house 1 gets L1, house 2 gets L2, house 3 gets L3, house 4 gets L1 etc.
3 phase is generally only used in commercial properties, they only need one 3 phase supply, and can take single phase supplies from that 3 phase, usually splitting loads to keep the phases balanced (a large room may have 3 sets of lights, one on each phase)
Motors can be wired as star or delta, or even use star/delta start/run
Because we are all 240/415, our cables can be smaller, this saves on copper.
New to the electrical game watched most but not all your videos really enjoy the authenticity you bring wish more people would be teachers of the craft instead of worrying about what their gonna earn from it
#toeachoneteachone
Ohhhhhh boy...you just can't leave out the earnings! What with the overtime, the weekends, the holidays! Time and a half, the double time, the TRIPLE time! The call outs, the storms, the wind-sheild TIME!! And everyone's pal: UNCLE SAM will be riding shotgun...for heavens, * DONT LEAVE OUT WHAT YOU'LL BE EARNING!! 😘😜🙄
Thank you for this video, I love this style content and how you explain things is fairly easy to understand. I’m almost into my second year in the apprenticeship and you have explained so much about transformers and systems that I haven’t understood for my previous time. Thanks man, I really appreciate this video.
In Serbia we use standard EU system. It is actually German standard and it is very neat and reliable. Street transformer is always in wye configuration. Central point is grounded and that is neutral comming from transformer. Between phases you get 400-420V, and between neutral and each phase 230-240v. It is safe. Nobody here is electrocuted, and every household has 3 phase system. It is very practic especially who has a workshop or other business requiring strong motors for woodcutting, or other appliences including electric heating that is allowed to consume 24kW of power per house. Every pole transformer here is rated for 250KVA, 400KVA, 630KVA and 1000KVA. I havent seen stronger than 1000. Great video, keep on going!
Been an electrician for almost 5 years that’s the only way I’ve heard it explained that I understand
Real talk!
Wow
I thought he meant he's asked for an explaination and everyone told him they were an elwctrician for 5 years and that was the explaination.
@Walkr he might have been a helper on a romex crew for four years. Not much to understand wiring houses.
@Walkr why? There's multiple different types of electricians most residential and even most commercial electricians don't know anything about industrial. And vice-versa. Also we're in a new era of people who think because they do some electrical work they're a electrician and they don't even know how to use a code book and thats the problem.
Now I am glad tho be an electrician in Europe where we have 230V(/400V) system everywhere. Small houses and huge industrial companies run on the same system
Some countries still have 230V three phase system. In France it's almost extinct, only found in some old factories with private transformer, but in Belgium and maybe other countries both 230 and 400V systems still coexists. Depending on the cities or the street you can have 1 or the 2 systems.
I was told it's a real pain in the ass for music festivals or concerts tours. Electricians often have to rewire the panels depending on the voltage
@@lionnelc13 Norway have a lot of 230V IT/TT (Delta configuration) , but greenfield construction is with 400V TN (Y configuration).
A lot of old houses or small apartment only have one of the phases into the building, so unless you have a Renault Zoe, you won't notice it.
@
Simon Schertler yes, i'm glad that i'm an electrician in Germany with the 230V (/ 400V) system. only the plugs schould be the same across europe (the world. i think, the poland has the best plug: germen plug whit a ground pin).
@ Thank God for switch mode power supplies, and variable frequency drives.
In Amsterdam are parts with the old system with 2 fases, each 127 VAC. Making the 220 VAC between those fases. 127 x sqr(3) = 220 VAC
Now many countries in europe have 230 VAC and maby in the future 240 VAC. More voltage, so we can deliver more power through the same wires. The current determents the wire gauge, so to get more power (P=UxI) we're getting higher voltages.
Same for the higher voltages, 380 VAC come from 220 x sqr(3) and the newer 400 VAC comes from 230 x sqr(3).
One thing I will say is you were demonstrating 277/480 on a delta connection rather than a wye.
It’s called trigonometry. If you draw a dashed line from the top of your delta transformer to the center of the base where you tapped the ground, then you just made two right triangles. You know both sides a can use trig to find the base.
-48VDC is extremely common in telco systems
And PoE (power over ethernet), and a lot of small-ish solar setups. (off-grid, RV, etc.)
52VDC in the newer systems?
Ultra low voltage - 50 volts and below, low voltage - 50 to 240 so typically 120/208/240 volt systems. Medium voltage is 277 to 600 volts. High voltage is anything above 600 volts. That's just how I differentiate it I know this an old video but I figured I'd put it out there anyway. Then there is data systems, internet Telcom all that and well we just shit talk the data guys cuz why not. Nah I'm playing got a buddy who does internet and security systems he's great but nothing of his blows up, shorts out, arcs or sparks and what's the fun in that.
a wye transformer allows you to transmit high voltages with very little current, whereas the delta virtually does the opposite [allows high current]. such is why transmission lines ie high voltage use wye transformers. typical uses for delta transformers are for industrial uses, but again, they themselves are fed with wye transmission lines. Some deltas have a grounded lead in which they most definately require a ground fault detector/protection.
the possibilities are numerous ie wye-delta, wye-wye, delta-wye, delta-delta. each transformer has their own uses, step up, step down, isolation etc.
because i couldn't/wasnt able to adequately explain myself...please check out this guys vids for some relatively easy understanding[easy for me anyways] of what i'd already learned going through my 3 levels[in-school learning] as an apprentice.
ua-cam.com/video/rEiukQLCVao/v-deo.html
the way "you" explained deriving something like 120/208 or 277/480 is "almost" factually wrong. i say almost because while it could be done your way, and in a few industrial settings it is, that is not how anyone ought to be doing it nowadays[safety reasons etc]. if you want one service and two different 'systems' of voltages, you'd keep your wye sourced power as your main and feed a secondary wye-delta transformer if you need high current and different voltage from your standard 120/208y main service.
K Hills bro, what are you rambling on about? Nothing he said in the video was incorrect. He wasn’t telling anyone how to “do” something. He was just explaining how the voltage numbers work out for different types of transformers.
i didnt want to bring it up, but "you" brought it out, ..:
i understand what he's talking about and trying to explain. but he couldnt have done it any worse than you calling out that "he" didnt do anything wrong. your obviously not versed or couldnt be, in the the electric arts lol..[sry for the pun]. i would not have shown or taught voltages "that" way[his way] because i know better and have a better understanding.
when i said i didnt want to bring this up, i meant this guy teaching it er..."elec u" etc doesnt have a very good understanding of how shit works. ie transformers. i wasnt trying to literally call him out, but i did leave a link to a guy's vid who knows fuck more than this guy.
lmao, sry, im being a bitcx. my grief is not with you, its with elec u. ive done calculations and such way back when and i remember my lectures etc when i was doing my level 2 and 3, and it annoys the hell out of me when i see :yes this could work; but it is almost never done and i could think and draw diagrams to more easily explain this crap.
mostly because i dont want people thinking they can just "tap-off" a 3 phase delta transformer no problem...lmfao!!
You have no idea what you are talking about. I am an electrical engineer. I design systems using a delta-delta and delt-wye every day. Why in the hell do you think a wye transformer allows you to transmit high voltages with very little current, but a delta doesn't? Have you ever taken an engineering power systems course? You are COMPLETELY wrong when you said, "a wye transformer allows you to transmit high voltages with very little current, whereas the delta virtually does the opposite [allows high current]. such is why transmission lines ie high voltage use wye transformers." Where in the hell did you learn this? Did you create this in your head or did some other dumb-ass tell you this?
You get 208 by using (a)^2 +(b)^2= (C)^2. The delta configuration is a triangle.
(b)^2= Sqrt of (C)^2 - (A)^2
a=120
c=240
With the 3 phase 4 wire delta system, the NEC requires you to write or put a warning label on the panel in question " Caution, B phase is 208 volts to neutral.".
Not the only label tho correct. High leg wild leg can be used too correct
If I have a three prong twist outlet that is 208 is there any way to use that for an appliance rated for 240 like a dryer or oven? (I’ve got no 240 outlets in my building). Or do I need to run a new 240 line from the breaker to run 240 appliances
American electrical supplies are nuts, glad that in Europe we have a unified system .
220 to 250 depending on where you are, corner grounded delta are also present
You have 230/400 and 400/690
Europe isn't simpler, it's just different
I am wiring a 230volt three phase hydraulic pump from a Lincoln welder/Generator three phase Delta 240volt. My question is do I just run the three hots or do I also wire the neutral to the pump. Thank you I would really appreciate your answer.
Can you explain three phase 240 a bit better?
3 phase 240 is a delta low side, your not going to see it much at least in my area. They do it so they can center tap one side and get you 120v single phase. Most low voltage three phase you will see will be 208v, which is a wye configured transformer.
@@josephkordinak1591 thank you. I'm in the business of installing battery chargers and have ran into 240 3ph once in the last year but 208 a handful of times. Thank you for the explanation
In 1947 thru 1985 their was low voltage controlled lights in some more expensive Houses ...28.5 volts energized from a transverter to a relay that would turn the light on with 120 volt
Not bad man. Pretty good description on delta. There’s more into why there’s 208 but than we’re getting into engineering and graphs.
he could have just described it as vector math and leave it at that. for someone that might not know, it might have helped. other than that, very good description
I ran across a high leg on a residential service upgrade. It was confusing because it was a house 🤔. Here I come to find back in the day it used to be a shoe repair shop with living quarters upstairs for the shopkeeper 😂. They actually ran 3 phase into neighborhoods for these small mom and pop shops! There were 2 separate services, single phase for the upstairs and 3 phase for the shop. And it was all still fuses! It was pretty scary looking actually 😂Luckily I checked the voltages before I hooked the service up LOL.
If u see a panel with every 3rd breaker available. Good chance that’s ur high legs. Double check ur voltage
Not spare 120
All this 3phase stuff makes sense if u understand physics. And vectors
What's your vector, victor? Huh? Over. Huh?
Hahahahahah ....understand physics... you speak like a peasant
Air condition condensor I saw needed 3 phase power. 240 Volts on each lag to run Compressor?
Could you explain this? Was a Wawa store with 5 AC Units?
Btw my journeyman taught me all of these calculations a while ago and I thought I had a decent understanding of it but once you explained I feel like I get it way better now. Appreciate you Dustin.
Poe = 24v dc and Poe+ = 48v dc it’s to power cameras and switches. It’s considered low voltage since it doesn’t move a lot of current. All this power runs across an ethernet cable.
I went to community college for two years ,and My respect for you bro ,you know what you teaching,
So would our 3 phase 480 system at work be a center tapped delta? Our B leg is 420V to ground and our electrician was really leery of it.
Most 3ph motors in the factory I worked at were 550. Had one wacky machine that had , I think, 308v motors. Machine had its own transformer in the control cabinet.
So I get how on a 3 ph 4 wire 480v wye you get 277 to neutral on all phases. How about a 4 wire 480v delta? Will there be a high leg and if so what voltage?
I am a seasoned electrician of 34 yrs and I enjoy how Dustin puts things in layman’s terms which is a gift and not easy to do! He did however forget to mention if your not a licensed electrician to stay away from higher voltages like 208, 277 and 480 volts. They all can kill you quite easily. Especially 480! Nasty! Don’t play around please if you aren’t a professional...keep up the great work Dustin!
How do I connect a breaker for a Ac on three face panel ? How do I pick the 120 volts leg ? Because one leg is 120 y the other one is 208 volts :/ I know how to do on a 2 face panel , but in three face I’m confused 😬
Clear as mud😁 Brings me back to my lineman school days. God I hated math.
I think we can all agree math is definitely not fun, however please dont use one of The Lord Jesus' titles in vain.
@@kylelikeskjvbible that’s actually his sons name not one of his titles but I see your point.
On a single phase 120/240V..hot to neutral will be 120V..hot to hot 240V on a single phase..
In Europe, it's simple, it's 3x400/230V
It's simple here too.
I have seen 3 phase panel coded as 208 but actually 3phase Y with a open delta. After that I always checked the voltage no matter what the tape said.
The 600Y/347 system is mainly used in Canada.
Jolyon Welsh we’re starting to get rid of 347... too many accidents
@@trezzer53 still very popular here in Canada. A lot of new jobs in Canada are still be specified as 347
c31979839 typically 347 is now used in underground parking lighting, luckily now lighting is 120v supply w 0-10v dimming systems which makes it a lot safer
@@Nick-bh1fy 347 volts is naturally a byproduct of the 600 volt Wye or star system. One almost only uses it out of convenience. There are times when you might have a 347 volt source nearby. And you would have to all the way on the other side of the building to find a suitable 120 volt source. It is typically used for industrial and commercial lighting in Canada.
We have 600,480, 347, and 277 all in the same shop.
And 10,000V input from the lines.
As an electrician I commonly wire motors 120 , 230, 240, 277, 300, 480, 600, 1200, 1460 and up. Some are 200 amps some are as much as 5000 amps.
I wire and manage transformers that step up or step down in the ranges mentioned above as well as voltages of 5kv,11kv,22kv, 33kv, 45kv, 120kv ....
Low voltage
Intermediate voltage
HIGH VOLTAGE .
Love the content, this video was good can you do a demonstration with wire colors and physical materials , would love to see this broken down barney style, thanks
We bought an eco smart 27 electric tankless hot water heater. It takes three different 8 gauge wires with three 40amp 220v breakers We are thinking about taking it back because I have been told it will dim the lights when it comes on. Is there anyway to fix that? Awesome video, thank you.
Install 12v led lights😁
@@saffalife8831 would that be like LED lights
Yep 12V LED with drivers
@@saffalife8831 thank you so much awesome videos
Well done on your computations! I enjoyed learning the separation between voltages on single and three phase! Keep up the good work!
Can I please please please get a copy of the script to this video? So I can get a better understanding.
4:40 That explained the 208/240 and also why some 3 phase have neutrals. Thanks!
Neutrals for anything with lights as a rule of thumb I always understood
I am trying to install a forklift charger for a customer. It’s rated for 208V/240V, 50amp 3-phase. The panel is 480Y-277V 3 phase. Is this possible?
You'd have to come out of the panel to feed a step-down transformer, 480-240V works fine since 240V draws slightly lower current for a given power draw. In this case you'd likely wire the secondary as a delta. You could also use three 480-120V transformers and configure a 277/480V to 120/208V set-up for the charger.
The 208 high leg is engraved in my mind now. Few months back i was landing wires for 120v plug inside generator enclosure. Picked the first unused 20 amp breaker i came across, might have been in a hurry. Sent 208v and cooked a $600 battery maintainer. I’ll never forget again. On a different note can you do some videos on why you would use dc versus ac in some applications like motors, controls, etc? Love the videos man your a great teacher!
All right I have a guy that bought a 208 V Brewing System but the power coming in is 120 240 single phase is his Brewing System going to work? I feel like even if it does work though it's probably not going to be good are the $30,000 piece of equipment
You might want to contact the manufacturer and make sure the 208V brewer is acceptable on 240V. A 208V rated heating element connected to 240V will run hotter than designed and although it probably won't burn out right away it will shorten the life and void any warranty. You could use a autotransformer to lower the 240V down to 208 and that's a common application for autotransformer, aka buck-boost transformer. Hope this helps.
In philly we had a "two phase" system fora long time. There are still some two phase buildings around. to supply them from a three phase supply you use a transformer connection called a "Scott- T". You can also cheat a bit and run two phase motors off of the delta with the center tapped winding and getting 240/208 two phase. The phases on two phase are 90 degrees away from each other
I had an old instructor he said they called those open bank sytems. The way the xformer gets it voltage like delta and wye open bank was those
@@kennethdunklin278 The two-phase transformers weren't delta or wye. The phases were at 90 degrees and not 120 degrees. They were more like X or T connected. I know it's all strange unless you worked on the old Philadelphia systems and buildings. It was really a crappy system that Philadelphia adopted in the beginning of utility power and we were stuck with it for like 50 years or more.
"In the early days of electrical engineering, it was easier to analyze and design two-phase systems where the phases were completely separated.[4] It was not until the invention of the method of symmetrical components in 1918 that polyphase power systems had a convenient mathematical tool for describing unbalanced load cases."
en.wikipedia.org/wiki/Two-phase_electric_power
upload.wikimedia.org/wikipedia/commons/thumb/a/af/Scott-T.JPG/400px-Scott-T.JPG
I'm also pretty sure it's covered well in "American Electrician's Handbook" www.amazon.com/American-Electricians-Handbook-Sixteenth-ebook/dp/B00COKLSVO and in "Electrical Machines Drives and Power Systems" www.alibris.com/search/books/isbn/9780130824608?qwork=1985923
@@cindytepper8878 Do you know if loads were separated like power and lighting to balance loads or more like just stab them in and turn em on? Im sure like now days unbalance loads need a return but we havent always been on a grounded system. Early days I was taught used to be ungrounded.
@@cindytepper8878 Ok it is a different system than open bank and I see how they get the 90 degrees too. Literally a "T" thats cool. I could see it being assumed as a Wye or Star but its definitely not. Hell yea, thank you for sharing this.
@@kennethdunklin278 Here is one of the crazy transformer connections that was most common in Philly. It was 5 wire, 4 hots and a grounded neutral
qph.fs.quoracdn.net/main-qimg-061bc48b1f8cece814845f7359c0f25a
It was highly inefficient in it's use of conductor material. I'm having a hard time remembering how you got the load balanced on the primary 3 phase supply side of the transformer. It's been a long time since I've been involved in any 2 phase systems. I think the last one was an emergency generator for the Philly Youth Study Center (kid prison) and I remembering it being a nightmare. That had to be at least 20 years ago. I'm trying to remember the details
Bought a heater 2YU37 (rated at 277V 1ph) -- but I need to run it on 240V 1ph. Thinking the heating elements will just be less efficient and the motor will only run a freckle slower. Am I missing something? Getting a you can't do it, from many others.
You should check with the manufacturer to see if that's acceptable. It probably won't hurt, the biggest concern being the motor. A heating element rated at 277 volts but operating on 240 volts will produce less than rated output. Bear in mind, the NEC requires you to install equipment in accordance with manufacturer's guidelines.
16V/24V also used in many thermostats for furnaces, etc.
NetworKing often converted from transformers with dual-input 240/120VAC primaries.
Certainly well taught, kinda wish i saw some sinwave goin on to explain why the sqrt3 occurs, and thus also have the wild lag... Buh regardless of that i'm glad the white board came out. Being Canadian i defiently know 120/240 120/208 347/600 but what do y'all in the states typically come across, is 600v a thing there?
In the states we rarely use 347/600, instead we use 277/480 9 time's out of 10
24 v Heating and air-conditioning systems thermostats
That's the first thing that came to mind. (not just to the thermostat, but to control relays/contactors, too.)
Not sure if it’s important or useful but when you plug 120 and 208 into the pythagorean theorem you get roughly 240. Curious as to why it doesn’t work for 480/277/240. Any insight?
If you're referring to the 240/480v 4 wire delta the high leg is about 415V, or 240*1.732 =415.68. The same formula applies to the much more common 120/240V 4 wire delta, high leg voltage = 120*1.732 = 207.84, or 208V.
You should do a video specifically on high leg Delta
I think I would have added that most 5 volt and 12 volt services are usually DC, but there are some low-voltage stuff that is just stepped down AC, for example, most residential HVAC thermostat controls are 24 volt AC.
Can you do a video on panels with high legs and how to place your Breakers in them for 208v and what's the high like for
It’s simple. On that system, every third position on the buss bar will be 208V to neutral/ground. The rest will be 120V to neutral/ground. Just use your multi-meter if you’re not sure. High leg is for equipment that requires or can use 208V.
@@RB-xv4si thank you
Only place I ever seen run on it was some of the equipment in older Dairy Queens
Bobcat Sterling I’ve never come across it in my life. Just heard it talked about all the time.
The high leg is supposed to be the red phase (B phase in USA and A phase in Canada - don't worry.) And, you are only allowed to use it in a three pole or two pole breaker, and never with a single pole breaker. There is a lot more math behind it, much more than a text comment with a sale to explain. (Look up open delta on Wikipedia and that my explain more, though I've not actually looked there for this info, as I learned this in my apprenticeship school.)
277/480V 3phase bank neutral floating
This is the best tutorial I have ever seen on this subject. Great job Dustin!
Good stuff, as an instructor you make it easier to understand. I looked through your uploads and did not see any on 240v. I am specifically interested in ; add a 240 to a sub panel for welder, the difference in wiring to sub vs main panel, why the white/ common is not used, and what happens if it is wired to the wrong buss... I have a couple of electrician books and have asked a few folks that supposedly are certified, but have gotten a little conflicting information and now I am majorly curious...
Get a copy of the latest NEC
Good Job explaining. As an electrician most of this was just taught and taken as fact. It wasn’t until much later at a Russell Electric School that the odd voltages were actually explained. In single phase the two legs are 180 degrees apart (sign wave) three phase are actually 120 degrees apart so the differential between legs will never be the sum of the different legs to neutral since one leg reaches the top of the voltage curve while either of the other legs at that instant has less potential related to neutral. That explains where we get 208 v 277 on 480 Volt systems and 2400 on 4160 volt systems.
I run into the center ground delta all the time in my area (northern PA) I work in a lot of hospitals, schools, and restaurants where we have to be aware of that wild leg but I have never seen it marked even though it really should be. Also I love your channel, I am HVAC/R tech and due to my job (I fix restaurant equipment and HVAC) I find myself needed to know a lot more about electrical than your average HVAC tech and your channel has helped a lot.
You forgot my favorite low voltage: -48v. Yes, I have a favorite low voltage.
Where is -48v used typically? Never seen it.
@@jaythompson5102 All over telecommunications I believe. Power over Ethernet being where most people see it, but anything in a telecom rack has a good chance of running off it. Someone correct me if I'm wrong, I used to work at the phone company, but I wrangled bits, not amps.
Sean Reifschneider yep, I work with carrier cell equipment and -48 is still everywhere. ATT being the first to use it and still do.
Most industrial controls are 24VDC. Mainly because per nfpa70e its finger safe
Yes, telecommunication systems typically run on -48v to -52 dc. If you take a dc voltmeter and measure between the two wires on a land line coming from the phone company, you should see -52v dc.
If you have 2O8 volts, you have 3 phase in the house. Normally don't see that on household current. 3 phase what I remember to ground is, one will have a higher voltage leg as the other 2 are about the same. I hooked up a 220 volt max car lift to 240 volts and felt uncomfortable about it for a shop. The shop owner sweared who sold him this uses 240 volts on them all the time with no problems.
What you are thinking of, is a high leg delta, common in rural area and usually seen only in older commercial buildings, but may also be found in newer construction as well, so always verify voltages before hooking stuff up. 120/208V wye is most common today, because each phase to neutral is 120V, and thus makes it much easier to balance the system when there's a variety of single phase and three phase equipment in use
120/208V single phase is actually very common in apartments, townhouses, condos and hotels. In these buildings, each individual unit gets fed two out of the three phases along with a neutral and ground, while the elevator and main HVAC systems run off of 208 three phase.
In very rare cases, three phase can be found at a single family dwelling. Some utility companies will not install a single phase service larger than a certain size, such as 400 to 600 amps, and this might be the case for very large, custom built luxury homes.
I’ve always called it a bastard leg instead of a high leg
Yes sir
Dustin, how does an industrial facility that gets supplied three phase 480 make 120v for standard lighting, 20 amp outlets, etc.? Do you guys set up a transformer similar to what would be on a residential pole to center tap one of the phases?
Yes, take a shopping mall for example. Most likely they will bring in 277/480Y 3ø. The 480V is used to power the elevators, escalators, and HVAC systems. The lighting will probably be 277V (if you look closely on LED drivers, or electronic fluorescent ballasts, you will probably see 120-277V markings, that's why) This is a very efficient lighting system because voltage drop will be minimal, and it's easier to balance the loads on the phases. There will be transformers in different areas of the mall for stepping 480V to 120V, or 480 to 120/240 to provide the 120V loads,
I know that these videos take a lot of time and effort on your end Dustin, but being an apprentice,these videos you do help a lot understanding electrical. Thank you for taking the time to put these together! It would be awesome if you can do a voltage drop video and understand the NEC and like ampacity and things like that.
Don't forget the stinger leg on a Grounded Center Delta, you'll get 208V to ground. That's how control circuits in equipment gets damaged if not careful
Fortunately these services are less common today than they were 50 years ago, and some utility companies no longer install 120/240 3 phase 4 wire delta in a new installation; the utility will provide you a 120/208Y system instead. Nonetheless it's critical to check the voltages with a suitable meter to avoid costly mistakes.
For those interested, the main reason power companies supply a 3 phase with 208 volt high leg is because they can bring good quality 3 phase power to a remote location(e.g. farm) using only two high voltage phases called V phase. Saves a LOT of money. As rural areas build up with new construction,both residential subdivisions and industry, it becomes more economically feasible for the power company to supply full three phase power. For that reason High Leg installations are slowly disappearing across the country but many still exist, so be careful out there.
In a Wye configuration one can bring 208 three phase or 120 single phase into a building. How can 240 v be delivered?
If 240 volts is required for a piece of equipment, you could use a buck boost transformer, to step 208 up to 240 volts.
Nice explanation!!!
I've herd it explained a million diffrent ways and this was the clearest so far...mike holt would be proud😁
Love the BEARD!!!
Love the configurations, and the beard...keep it up bro...
I read the thumbnail as 120 quadrillion volts
If you draw two 120V lines in two phase (180 degrees from each other), then visually measure peak to peak it will equal 240V. I think if you draw out a three phase (120 degrees) and visually measure across the peaks the most you can get is 208V. It helps to see why it is 208V because the peaks of each phase never fully line up like two phase does. That's why you can't get the full 240V in a three phase. I didn't know about the square root of 3 trick to find that number quickly. Nice tip!
You can get the full 240V three phase in a deta configuration, and the best of both worlds (kind of) with a center tap on one of the transformers to give 120/240V single phase just like you'd find in your home, the winding furthest away from the center tap is the ghastly 208V stinger leg, you are not permitted to use the stinger leg to neutral for running single phase 208V loads.
This is the exact reason why. Sqrt3 is useful for math and it comes from the RootMeanSquare (RMS) way of measuring AC voltage
If you open a panel door and see every third single pole breaker has a blank instead of a breaker HEADS UP!
Why?
Some power companies avoid a "wild leg" situation by only using the wye-delta bank for three phase. A separate (fourth) transformer is used to supply single phase.
I work in Utilities, we don't install a fourth transformer to provide a customer 3 phase and a single phase service. A bank with 3 transformers, we change the internal windings to achieve the desired voltages. For example, transformer 1 is (25KVA) in parallel, transformer 2 is in series (50KVA) and transformer 3 is in parallel (25KVA) giving the desired voltages of 120V/208V/240V. The size of the transformer for one is doubled to accommodate the additional single phase load.
So what reading would you get on a single phase 120v circuit with a dropped neutral?
It depends on where the neutral is dropped and if it's part of a multiwire branch circuit. A dropped neutral at a receptacle fed from a two wire circuit would read 0 volts. A dropped neutral at a main panel/sub panel/multiwire branch circuit would give a varying reading depending on the load balancing between L1 & L2 to neutral, could range from a few volts above or below normal to 240V on one line and 0V on the other because everything downstream of the dropped neutral is essentially in series with 240V.
Need some help! perhaps this would make for a good video. Installed 10/3 for dryer 30amp circuit and wires get very warm when machine in use. Receptacle gets very warm also. checked all connections and measurements are ok. The code calls for 10 gauge as a minimum. I’m not comfortable running the dryer when things are warm like that. Any advice anyone?
God damn it.
Another weird american system.
Over here in the EU we mostly have 230/400
The whole gauge stuff wasn't enough, was it?
Interesting, In Australia/NZ and Europe, you're low voltage is regarded as ELV and SELV, everything above 80 is low voltage, with 1000+ is high voltage.
The high leg is so important to explain to apprentices and experienced electricians alike. I was completely unaware of it until one of the guys at my work described it to me when we were doing work in an old building. I am aware of at least one case where an apprentice turned professional overnight and decided to take on side work during his studies. He ruined a $3,000 commercial refrigerator running a dedicated receptacle feed and connecting it to the high leg.
Hi sir,
Thanks for a great video.
I would like to ask about 832Y/480.
Why does the 832Y indicate?
I saw this on an electrician test but couldn't understand what it stands for.
Could you please help?
Thank you, I appreciate the time and the technical side of your explanation!! I hope more individuals your age continue to do well for all of us that are close to retiring! You are amazing!!