Love your channel! As an electrical engineer with practical experience I’d like to offer the following. One exception to needing (for example) 40 amp wire on a 40 amp breaker, is when the load is a motor. With motors, the wire only needs to be 125% of the motor full load amps. This is often less than 40 amps, in this example. The wire sizes you refer to for example 1/O for 150 amps, assumes the conductor is not oversized due to voltage drop, in which case a larger wire is required. A regular screw driver might be considered by some to be insulated, but an electrician only uses screw drivers that are specifically rated as insulating, such as manufactured by Klein. Concerning your waving of a screw driver near the panel phase incoming lugs, and later pointing a finger near busbars, I wish that wasn’t in your video as it concerns me that people might think that is okay to do that. Only professionals (and I think you indicated you were/are an electrician) know what they are doing when they do that, and the camera angle doesn’t help show that you are actually not too close. No lox is popular in Northern California where I am, but actually per UL is it not required with today’s AL alloys. Otherwise, very good video with lots of great information clearly presented.
The tip about using the non-contact thermometer is right on. These units are now quite inexpensive. Really helped me verify that I was successful after taking apart and cleaning crusty connections at my water heater. Then I checked the terminals I hadn't worked on and found on more that needed attention. The two terminals on the element will of course be elevated, but they should be equal. Now I'm kicking myself for not pulling of the bottom panel for the lower element, the unit is in the well pit, a pain to access.
Just found your channel because our water heater wasn't working and I have to say, your videos are AWESOME! You explain things very clearly in plain language and it helped me understand everything that was going on. We now have hot water and my wife thanks you very much!
Glad you enjoyed it Dan! Be sure to rate thumbs up, consider subscribing, and look over my extensive video playlists below for many other videos of interest to you. Taking one minute to share a link to my channel with others on social networking sites would be greatly appreciated. Thank you ua-cam.com/users/electronicsnmoreplaylists
Excellent tips on what to look for if there is an electrical issue. I would add that it would be wise to always start at the circuit breaker panel if there is an electrical issue to ensure voltages are what they should be. This might save you or your A/C specialist from thinking your (expensive) A/C compressor was bad when the real problem might be a loose circuit breaker panel connection (inexpensive fix), per your video. Don't ask me how I know!
Great Video. You explained very well. I have installed many panels but never thought about using the tools you have shown for testing for problems at the panel.
I've seen many older panels over the years that were, some 50-60 years old with no problems, but for a new subpanel I'd do like the NEC says, which is to separate the neutral and ground. Thanks for watching!
OK. Purchased the single pole breaker and new element. Almost ready to do this. I see and understand what to do at the breaker box thanks to this video. I would just like to be sure of what to do at the water heater. The water heater is still connected to power as installed. One black wire is connected to the top pole above the reset button. One white wire is connected to the element. And of course the ground is also connected to the screw provided. There is a junction box above the water heater and since there is only one black wire and one white wire and bare copper ground wire emanating from the gooseneck extension from it I assume the two breakers have been wired together inside leaving just one pair at the connection end. My question is; Is this connection still valid?
+Robert Potter I would love to keep assisting you, but as I stated earlier, I have too many other viewers asking questions. I supplied videos to my viewers which are highly detailed/well explained. It is up to them to use the information in my videos as a tool. If I feel that a viewer lacks the knowledge or skills for a particular job, then I will not assist them(excessive questions is normally a clue). I have Disclaimers on many of my videos, as well as in my channel main page "About" section. Anything you do is at your own risk, and you accept all responsibility for any damage or injuries which may result. If I helped people at a higher level, like you, then I would be putting myself at risk. Thank You.
You're welcome! Be sure to look over my extensive video playlists for other great videos of interest to you, and most importantly share my channel with others. Thank you
great video. i just had 2 questions. other electricians on UA-cam say that splices inside the panel are okay. are there conditions that would make this acceptable or unacceptable? such as the wires not taking up more than 75% space inside the panel. if the wires are too short to reach the breaker, you can extend them. but you can't use the panel for circuits not originating from the panel. is this correct, in your professional opinion? i'm studying to be a home inspector and need to know when a splice inside the panel is appropriate, if i come across it. thank you
Hi there! Generally inspectors don't like to see splices inside electrical panels, but there are times when a splice is unavoidable, such as when a wire is too short to reach a circuit breaker. You cannot use the electrical panel as a junction box. You can find out more by referring to the NEC online. Thanks for watching!
Is there a certain distance that you look for the insulation to have been trimmed back before the wires connected to the breaker? For instance do you like to see a half inch or 1 inch of bare wire after the wire has been hooked up to the breaker?
electronicsNmore You mean a half inch of wiring insulation plus the amount of wire insulation that it took for the wire that is connected to the breaker? So a half inch should be coming out from the breaker screw a half inch of bare wire?
Pretty sure the voltage across the hot lines would be something in the order of 208 volts RMS since this is AC and the phase difference just wouldn't allow 240V to exist there. Wanted to add that because there is plenty of confusion on this topic, let's try to get rid of some :P
Nope. There is a difference in industrial / commercial power and the step down transformers used compared to residential power in the United States. While some step down transformers do supply 208 volts to equipment or lighting that requires it, residential power can be 220 or 240 volts split phase. In your above post, if you are reading 440 volts from a phase to the bonded neutral, you have a problem since it should be 277 volts. Of course this is read with a CAT IV RMS compensated meter. Most meters on the market are RMS compensated which is an all together different topic.
You can find that info out online. I don't get overly concerned with every code, what's code today may not be code tomorrow. Just make sure the circuit is GFCI protected.
ElectronicNmore.........When they say 100 Amp, 200 Amp panel and you add up all the breakers in the panel, they almost always exceed the capacity of the panel box. What is the rule for sizing a panel box, knowing that every circuit breaker is probably not in service at the same time.
Yes, they do exceed the main breaker value. No one uses all circuits at the full breaker rating at the same time. :-) You can refer to the N.E.C. online to see how to calculate. Thanks for watching!
Great tips but isn't your panel dual phase because you have 2 hot lines coming in to it and you have 240 volts across the 2 phases? if your panel was single phase you would have 1 hot wire and only have 120 volts and if it was 3 phase like you said you would have hot wires and 480 volts
Something has to be understood here, the voltages you get at your house are at 120 (hot to neutral and 208 hot to hot) because that's the norm for domestic use, it has nothing to do with the amount of hot wires you have connected, in three phase systems for industrial use you get 440 volt ON EACH LINE to neutral and a voltage across hot wires of 440 x square root of 3, about 762 volts. These numbers are things we agreed to in order to manufacture one type for a lot of people. These voltages depend solely on the transformer you have in your area not on the amount of phases.
electronicsNmore do you have any diagrams that show the wiring on this system?, i would like to see how this works because when i measure the voltage between the hotlines in my system i get 208 volts and that is the voltage that should be between two 120 volt lines with a 120 degrees phase difference. Thanks for the information :p
RapiBurrito There're only two possible phase shifts (0° and 180°) that can exist between the two portions of a single winding. You should realize the difference between the "split-phase" and "three-phase" power systems.
Question. I have a hot water heater that is not receiving power. At the circuit breaker, each pole reads 120v to ground, and the two poles together read 240v. Just like they should. However, at the water heater, each pole to ground reads 120v, but the two poles together read 0v. Have I crossed wires somewhere, or is this likely a circuit breaker problem like you described here, like cleaning the bus bars?
Marcus Armstrong One 120V leg(wire) is open between the circuit breaker and the heater. There is no other cause. You many have a loose wire in a junction box between the panel and the heater. Thanks For Watching! Rate thumbs up, and share.
Not that your usage and explanation of Neutral/ground is inaccurate, but is confusing for most non electricians (and some electricians from experience). You also breezed over bonding rather quickly!
electronicsNmore that has little to do with making a video but in how you use terminology interchangeably. As I said your explanation is accurate that at the transformer and the main panel they are bonded. But you at one point, go to the neutral with your probe and call it ground.
Fire! The current flowing through the service entrance conductors and busbars would be allowed to double. Even though the panel may be able rated 125A, if the wire is only 4ga, then 100A is the max. Thanks for watching!
Major overkill. 1/0 copper (THHN) can handle up to 175A. If the run was over 100 feet, then I could see using one size larger(#1 copper) to compensate for a voltage drop.
Yep. The temperature rating of the wire is very important. You may have to use a larger wire. 60 deg C says 1/0. If using THHN, then #2 is fine. Refer to the NEC online. :-)
electronicsNmore it's the thhn thwn-2 mtw rated for 90° c, so with that size I should never get hotter than 60° c, a little harder to work with but it's already bought and overkill is totally underrated! There's no issues with oversized conductors right?
Ya know...watching you people in these videos stick your bare fingers towards the wires, lugs, bus bars in an open panel really makes me cringe. Would be much better to use a non conductive pointing device instead. Holy cow
I was struggling to get the wire in the breaker and this video showed two places to insert the wire and baboon! Electricity! Thank you so very much!
Glad I could help!
Love your channel! As an electrical engineer with practical experience I’d like to offer the following.
One exception to needing (for example) 40 amp wire on a 40 amp breaker, is when the load is a motor. With motors, the wire only needs to be 125% of the motor full load amps. This is often less than 40 amps, in this example.
The wire sizes you refer to for example 1/O for 150 amps, assumes the conductor is not oversized due to voltage drop, in which case a larger wire is required.
A regular screw driver might be considered by some to be insulated, but an electrician only uses screw drivers that are specifically rated as insulating, such as manufactured by Klein. Concerning your waving of a screw driver near the panel phase incoming lugs, and later pointing a finger near busbars, I wish that wasn’t in your video as it concerns me that people might think that is okay to do that. Only professionals (and I think you indicated you were/are an electrician) know what they are doing when they do that, and the camera angle doesn’t help show that you are actually not too close.
No lox is popular in Northern California where I am, but actually per UL is it not required with today’s AL alloys.
Otherwise, very good video with lots of great information clearly presented.
The tip about using the non-contact thermometer is right on. These units are now quite inexpensive. Really helped me verify that I was successful after taking apart and cleaning crusty connections at my water heater. Then I checked the terminals I hadn't worked on and found on more that needed attention. The two terminals on the element will of course be elevated, but they should be equal. Now I'm kicking myself for not pulling of the bottom panel for the lower element, the unit is in the well pit, a pain to access.
Just found your channel because our water heater wasn't working and I have to say, your videos are AWESOME! You explain things very clearly in plain language and it helped me understand everything that was going on. We now have hot water and my wife thanks you very much!
You're welcome Felix! Be sure to share my channel with others, rate thumbs up, and check out my video playlists. Thanks
Superb video - packed with accurate, clear, concise, and easy to understand content - THANK YOU!!
Glad you enjoyed it Dan! Be sure to rate thumbs up, consider subscribing, and look over my extensive video playlists below for many other videos of interest to you. Taking one minute to share a link to my channel with others on social networking sites would be greatly appreciated. Thank you
ua-cam.com/users/electronicsnmoreplaylists
Excellent tips on what to look for if there is an electrical issue. I would add that it would be wise to always start at the circuit breaker panel if there is an electrical issue to ensure voltages are what they should be. This might save you or your A/C specialist from thinking your (expensive) A/C compressor was bad when the real problem might be a loose circuit breaker panel connection (inexpensive fix), per your video. Don't ask me how I know!
Thank you for this informative video, do you know how to check ground rod resistance with a simple tool?
Best video I've seen on the subject yet
Great to hear Garrett! Be sure to check out my wide range of videos and share. Thank you
Great Video. You explained very well. I have installed many panels but never thought about using the tools you have shown for testing for problems at the panel.
Thanks For watching!
Excellent video thanks. Very helpful for home inspections.
Neutral and grounds cannot be bonded on subpanel right?
I've seen many older panels over the years that were, some 50-60 years old with no problems, but for a new subpanel I'd do like the NEC says, which is to separate the neutral and ground. Thanks for watching!
Great Video, the clip info is the exact problem I’m having
Thanks for the video =)
why short circuit happens on DB during tightening screws of loss wires when the DB main mccb is ON
OK. Purchased the single pole breaker and new element. Almost ready to do this.
I see and understand what to do at the breaker box thanks to this video. I would just like to be sure of what to do at the water heater.
The water heater is still connected to power as installed. One black wire is connected to the top pole above the reset button. One white wire is connected to the element. And of course the ground is also connected to the screw provided.
There is a junction box above the water heater and since there is only one black wire and one white wire and bare copper ground wire emanating from the gooseneck extension from it I assume the two breakers have been wired together inside leaving just one pair at the connection end.
My question is; Is this connection still valid?
+Robert Potter
I would love to keep assisting you, but as I stated earlier, I have too many other viewers asking questions. I supplied videos to my viewers which are highly detailed/well explained. It is up to them to use the information in my videos as a tool. If I feel that a viewer lacks the knowledge or skills for a particular job, then I will not assist them(excessive questions is normally a clue). I have Disclaimers on many of my videos, as well as in my channel main page "About" section. Anything you do is at your own risk, and you accept all responsibility for any damage or injuries which may result. If I helped people at a higher level, like you, then I would be putting myself at risk.
Thank You.
Excellent video. Thank you
You're welcome! Be sure to look over my extensive video playlists for other great videos of interest to you, and most importantly share my channel with others. Thank you
The way he taps with that screwdriver makes me nervous!
I've been doing it for decades. LOL
Great video with lots of useful information. Thanks for sharing.
Frank Graulau Thanks Frank. Be sure to rate Thumbs Up, and Share.
great video. i just had 2 questions. other electricians on UA-cam say that splices inside the panel are okay. are there conditions that would make this acceptable or unacceptable? such as the wires not taking up more than 75% space inside the panel. if the wires are too short to reach the breaker, you can extend them. but you can't use the panel for circuits not originating from the panel. is this correct, in your professional opinion? i'm studying to be a home inspector and need to know when a splice inside the panel is appropriate, if i come across it. thank you
Hi there! Generally inspectors don't like to see splices inside electrical panels, but there are times when a splice is unavoidable, such as when a wire is too short to reach a circuit breaker. You cannot use the electrical panel as a junction box. You can find out more by referring to the NEC online. Thanks for watching!
@@electronicsNmore thanks!
It is legal to make a splice in the panel in the US.
Is there a certain distance that you look for the insulation to have been trimmed back before the wires connected to the breaker? For instance do you like to see a half inch or 1 inch of bare wire after the wire has been hooked up to the breaker?
1/2" of the wire's insulation should be removed.
electronicsNmore You mean a half inch of wiring insulation plus the amount of wire insulation that it took for the wire that is connected to the breaker? So a half inch should be coming out from the breaker screw a half inch of bare wire?
Strip off 1/2" then insert the wire into breaker and tighten the screw. Done.
practical information, thank you...
Great video !!!
Glad you enjoyed the video Milton! Be sure to rate thumbs up and share my UA-cam channel with others. Thank you
Great video. THANK YOU!
Steven Oliveri Glad you enjoyed it!
Pretty sure the voltage across the hot lines would be something in the order of 208 volts RMS since this is AC and the phase difference just wouldn't allow 240V to exist there. Wanted to add that because there is plenty of confusion on this topic, let's try to get rid of some :P
Nope. There is a difference in industrial / commercial power and the step down transformers used compared to residential power in the United States. While some step down transformers do supply 208 volts to equipment or lighting that requires it, residential power can be 220 or 240 volts split phase.
In your above post, if you are reading 440 volts from a phase to the bonded neutral, you have a problem since it should be 277 volts. Of course this is read with a CAT IV RMS compensated meter. Most meters on the market are RMS compensated which is an all together different topic.
NEC 2017 Lighting fixtures above a pool must be installed at a minimum height of?
You can find that info out online. I don't get overly concerned with every code, what's code today may not be code tomorrow. Just make sure the circuit is GFCI protected.
Great Video.
Israel Cancel Thank You. Please be sure to share with others, and rate Thumbs Up.
Thank you for sharing. I've setup a few of these,back in the day.
All the best.
bobby
Thanks for watching and sharing Bobby.
electronicsNmore
You are very welcome
ElectronicNmore.........When they say 100 Amp, 200 Amp panel and you add up all the breakers in the panel, they almost always exceed the capacity of the panel box. What is the rule for sizing a panel box, knowing that every circuit breaker is probably not in service at the same time.
Yes, they do exceed the main breaker value. No one uses all circuits at the full breaker rating at the same time. :-) You can refer to the N.E.C. online to see how to calculate. Thanks for watching!
Great tips but isn't your panel dual phase because you have 2 hot lines coming in to it and you have 240 volts across the 2 phases? if your panel was single phase you would have 1 hot wire and only have 120 volts and if it was 3 phase like you said you would have hot wires and 480 volts
They cal it "Split Phase" one phase split. For the end user, yeah you could look at it as two phases 180 degrees apart.
Something has to be understood here, the voltages you get at your house are at 120 (hot to neutral and 208 hot to hot) because that's the norm for domestic use, it has nothing to do with the amount of hot wires you have connected, in three phase systems for industrial use you get 440 volt ON EACH LINE to neutral and a voltage across hot wires of 440 x square root of 3, about 762 volts. These numbers are things we agreed to in order to manufacture one type for a lot of people. These voltages depend solely on the transformer you have in your area not on the amount of phases.
No the panel is a single phase 120/240V panel. One 240V center tapped transformer is supplying power to the house.
electronicsNmore do you have any diagrams that show the wiring on this system?, i would like to see how this works because when i measure the voltage between the hotlines in my system i get 208 volts and that is the voltage that should be between two 120 volt lines with a 120 degrees phase difference. Thanks for the information :p
RapiBurrito There're only two possible phase shifts (0° and 180°) that can exist between the two portions of a single winding. You should realize the difference between the "split-phase" and "three-phase" power systems.
WOW!!
Question. I have a hot water heater that is not receiving power. At the circuit breaker, each pole reads 120v to ground, and the two poles together read 240v. Just like they should. However, at the water heater, each pole to ground reads 120v, but the two poles together read 0v. Have I crossed wires somewhere, or is this likely a circuit breaker problem like you described here, like cleaning the bus bars?
Marcus Armstrong One 120V leg(wire) is open between the circuit breaker and the heater. There is no other cause. You many have a loose wire in a junction box between the panel and the heater.
Thanks For Watching! Rate thumbs up, and share.
But if one of them is open, why are both reading 120v?
You are getting a loop back. Disconnect the 2 hot wires from the heater, then test them. You will see one wire to ground is ZERO volts.
Yep, you're right. The black wire reads 120v, and the red reads 0v.
Now trace the red wire back to the breaker. Case closed. :-)
The only issues I have with my panel are that it's a Common-Neutral system that's very poorly distributed...
So..........one bad breaker will disrupt the entire box?
No
Not that your usage and explanation of Neutral/ground is inaccurate, but is confusing for most non electricians (and some electricians from experience). You also breezed over bonding rather quickly!
Unfortunately not every video can be made perfect. :-) Thanks for watching
electronicsNmore that has little to do with making a video but in how you use terminology interchangeably. As I said your explanation is accurate that at the transformer and the main panel they are bonded.
But you at one point, go to the neutral with your probe and call it ground.
Those feeders look tiny.
Farmer Dave Service was only 100A
Farmer Dave if those aren't copper they definitely are undersized
They were #4 copper
just cirious what can happen if 100 amp main breaker was replaced with a 200 amp one
Fire! The current flowing through the service entrance conductors and busbars would be allowed to double. Even though the panel may be able rated 125A, if the wire is only 4ga, then 100A is the max. Thanks for watching!
If the utility lines and service entrance lines are sufficient size, you will have no problem.
So 1/0 copper on a 8 foot run to a 125 amp sub panel is overkill?
Major overkill. 1/0 copper (THHN) can handle up to 175A. If the run was over 100 feet, then I could see using one size larger(#1 copper) to compensate for a voltage drop.
electronicsNmore so you're saying #2 for an 8 ft 125a run?
Yep. The temperature rating of the wire is very important. You may have to use a larger wire. 60 deg C says 1/0. If using THHN, then #2 is fine. Refer to the NEC online. :-)
electronicsNmore it's the thhn thwn-2 mtw rated for 90° c, so with that size I should never get hotter than 60° c, a little harder to work with but it's already bought and overkill is totally underrated! There's no issues with oversized conductors right?
depends on the inspector. They can make you remove an oversize wire if they want to be difficult. Remember, they have the final say.
your explanation was good, your video was not great, to me you had some dark spots i could not see where you were putting the probes.
It was made a long time ago. My camera and lighting wasn't the greatest.
Ya know...watching you people in these videos stick your bare fingers towards the wires, lugs, bus bars in an open panel really makes me cringe. Would be much better to use a non conductive pointing device instead.
Holy cow
I know where I can and can't touch.
@@electronicsNmore No doubt about that but your viewers may not be that experienced
@@jburr36 Viewers should be smart enough to know they're not me, and be careful.
@@electronicsNmore but they aren't. And some are not adults