Sub Panel Ground Question

[rockcrawler]

I’m in the process of adding a second panel to my shop. I took the cover off the panel that is already in use and noticed that the grounds are not mounted separate from the neutrals. It appears to me that this panel was wired incorrectly. Am I correct? I purchased a grounding bar to mount to the panel so that I can move the grounds. I just wanted to make sure I was looking at it correctly. This is a sub panel that is fed from the main panel in the house.

 

[Poolshark314]

Yes if it is a subpanel you should separate the grounds from the neutrals. If there is a bonding screw (usually green), make sure that is removed as well. You should then have 2 grounding rods buried at least 6 ft apart and have them attached to the grounding bar you just purchased. Some people like to have 2 grounding bars in the box so they can run the grounds down each side.

 

[BreeStephany]

As Poolshark stated, because the primary panel in the shop is a SUBPANEL feed from the main panel at your house, grounds and neutrals must be separated and because it is a separate structure, it must also have 2x ground rods buried at least 6ft apart and connected via solid copper grounding electrode conductor sized per NEC 250.66. The bonding screw in your current subpanel at the shop does not appear to be installed, as it would be installed in the hole to the left of your neutral lug at the top of the panel bussing.

When you install your second subpanel in your shop, to be fed from the current 100A panel, this must be wired in a similar fashion but does not require ground rods, as the building will be grounded by means of the main 100A panel and its grounding electrode conductor / ground rods.

Your second subpanel shall have 2x line/ungrounded conductors, a neutral/grounded conductor, sized according to NEC 310.16 per the size of disconnect breaker that you place in the 100A shop subpanel and a grounding conductor sized per NEC 250.122 and the grounds and neutrals must be separate in this panel as well.

 

[sparky 1971]

To add to above, I hope the house and shop are the same building, but that red steel makes me doubt it. That looks like 6/3 Romex feeding it coming from below. It it's coming from the house underground, that's bad unless it transitions from another wire type that is suitable for underground. If it's the same building and just happens to be coming from below, but not underground, then carry on. Also, if it's the same building as the house, ground rods aren't going to be required for either sub panel, just get the ground bars and be done with it.

 

[rockcrawler]

Yes if it is a subpanel you should separate the grounds from the neutrals. If there is a bonding screw (usually green), make sure that is removed as well. You should then have 2 grounding rods buried at least 6 ft apart and have them attached to the grounding bar you just purchased. Some people like to have 2 grounding bars in the box so they can run the grounds down each side.

I checked for the bonding screw as soon as I saw that the grounds were not separate. It’s not in the panel, so at least that was done right. As far as the grounding rods go, I have no idea if they used any. I can see the copper wire going out of the bottom of the panel, but I don’t know where it goes.

 

[wyliesdiesels]

To add to above, I hope the house and shop are the same building, but that red steel makes me doubt it. That looks like 6/3 Romex feeding it coming from below. It it's coming from the house underground, that's bad unless it transitions from another wire type that is suitable for underground. If it's the same building and just happens to be coming from below, but not underground, then carry on. Also, if it's the same building as the house, ground rods aren't going to be required for either sub panel, just get the ground bars and be done with it.

Its definitely NM-b as you can see the paper liner hanging out near the bare ground wire.

 

[wyliesdiesels]

I checked for the bonding screw as soon as I saw that the grounds were not separate. It’s not in the panel, so at least that was done right. As far as the grounding rods go, I have no idea if they used any. I can see the copper wire going out of the bottom of the panel, but I don’t know where it goes.

is your shop a detached building and does this cable feeding the panel go underground? if so they used the wrong wire and it should be replaced

 

[rockcrawler]

As Poolshark stated, because the primary panel in the shop is a SUBPANEL feed from the main panel at your house, grounds and neutrals must be separated and because it is a separate structure, it must also have 2x ground rods buried at least 6ft apart and connected via solid copper grounding electrode conductor sized per NEC 250.66. The bonding screw in your current subpanel at the shop does not appear to be installed, as it would be installed in the hole to the left of your neutral lug at the top of the panel bussing.

When you install your second subpanel in your shop, to be fed from the current 100A panel, this must be wired in a similar fashion but does not require ground rods, as the building will be grounded by means of the main 100A panel and its grounding electrode conductor / ground rods.

Your second subpanel shall have 2x line/ungrounded conductors, a neutral/grounded conductor, sized according to NEC 310.16 per the size of disconnect breaker that you place in the 100A shop subpanel and a grounding conductor sized per NEC 250.122 and the grounds and neutrals must be separate in this panel as well.

So, I guess the twisted copper wire running out the bottom of the box is not allowed? I guess I’m going to have to dig around outside the shop to see if I can find a grounding rod.

 

[rockcrawler]

To add to above, I hope the house and shop are the same building, but that red steel makes me doubt it. That looks like 6/3 Romex feeding it coming from below. It it's coming from the house underground, that's bad unless it transitions from another wire type that is suitable for underground. If it's the same building and just happens to be coming from below, but not underground, then carry on. Also, if it's the same building as the house, ground rods aren't going to be required for either sub panel, just get the ground bars and be done with it.

Separate buildings. I have no idea what they used coming from the house to the shop. It was all part of the build.

 

[rockcrawler]

is your shop a detached building and does this cable feeding the panel go underground? if so they used the wrong wire and it should be replaced

It is detached. Well, ****. What kind of wire do I need to use to replace the one they used? This all worries me and I wonder what else they did wrong.

 

[sparky 1971]

It is detached. Well, ****. What kind of wire do I need to use to replace the one they used? This all worries me and I wonder what else they did wrong.

The first thing to do is see if the conduit runs all the way from the house to the shop or if the wire is buried. My vote is for the conduit, hopefully they weren't stupid enough to plant romex straight in the dirt. If it's conduit, black, red, white #6 and a #10 ground tied to the existing, which will be used to pull in the new. #6 would replace what you have, but if it's 2" conduit all the way back, you could increase the wire size and get yourself more power.

 

[sparky 1971]

So, I guess the twisted copper wire running out the bottom of the box is not allowed? I guess I’m going to have to dig around outside the shop to see if I can find a grounding rod.

That stranded copper wire is part of the cable assembly for what is feeding the panel and is supposed to be there. The ground rods would have another copper wire running to them and that wire isn't there. Don't waste your time looking for the rods, they aren't there.

 

[mike93lx]

If you run copper, you'd use either thwn or xhhw, whichever is cheaper/easier to get.

If you run aluminum, it's xhhw or MHF. If you have 1.5 or 2" conduit end to end, I'd recommend AL XhHw, two #2, a #4 and a #6. You can use up to a 90a breaker in the main panel to feed it

 

[rockcrawler]

The first thing to do is see if the conduit runs all the way from the house to the shop or if the wire is buried. My vote is for the conduit, hopefully they weren't stupid enough to plant romex straight in the dirt. If it's conduit, black, red, white #6 and a #10 ground tied to the existing, which will be used to pull in the new. #6 would replace what you have, but if it's 2" conduit all the way back, you could increase the wire size and get yourself more power.

They did bury a conduit. I had two run to the shop, one for power and one for all my CAT6 cables.

 

[rockcrawler]

That stranded copper wire is part of the cable assembly for what is feeding the panel and is supposed to be there. The ground rods would have another copper wire running to them and that wire isn't there. Don't waste your time looking for the rods, they aren't there.

Great. So I guess I’ll have to install two grounding rods and run a solid copper conductor from the panel to the rods. Do I just bury a section of solid copper conductor connecting the two rods together?

 

[sparky 1971]

Great. So I guess I’ll have to install two grounding rods and run a solid copper conductor from the panel to the rods. Do I just bury a section of solid copper conductor connecting the two rods together?

Yes

 

[sparky 1971]

Great. So I guess I’ll have to install two grounding rods and run a solid copper conductor from the panel to the rods. Do I just bury a section of solid copper conductor connecting the two rods together?

It won't be bad. Use the old cable to pull in new wires.

 

[rockcrawler]

If you run copper, you'd use either thwn or xhhw, whichever is cheaper/easier to get.

If you run aluminum, it's xhhw or MHF. If you have 1.5 or 2" conduit end to end, I'd recommend AL XhHw, two #2, a #4 and a #6. You can use up to a 90a breaker in the main panel to feed it

So I need 2 black (hot) #2 THWN, 1 white (neutral) #4 THWN and 1 green (ground) #6 THWN? My house main panel has a 100 amp breaker feeding the shop panel. The shop panel has a 100 amp breaker in it and I have a 100 amp breaker that will feed the 2nd sub panel in the shop. Are you saying I need to buy three 90 amp breakers? One for the main panel to feed the shop panel, one for the incoming power in the 1st shop panel and one feeding the second shop panel? My second shop panel is lug only.

 

[mike93lx]

So I need 2 black (hot) #2 THWN, 1 white (neutral) #4 THWN and 1 green (ground) #6 THWN? My house main panel has a 100 amp breaker feeding the shop panel. The shop panel has a 100 amp breaker in it and I have a 100 amp breaker that will feed the 2nd sub panel in the shop. Are you saying I need to buy three 90 amp breakers? One for the main panel to feed the shop panel, one for the incoming power in the 1st shop panel and one feeding the second shop panel? My second shop panel is lug only.

No.

That 100a breaker feeding this is too big. If you want to keep it, you need to go to #3 copper for the hots.

The main breaker in the sub can be larger than the feeder, so that could be a 200a panel if you wanted.

The feeding breaker is sized to the wire. The breaker in the sub is just a disconnect

 

[rockcrawler]

No.

That 100a breaker feeding this is too big. If you want to keep it, you need to go to #3 copper for the hots.

The main breaker in the sub can be larger than the feeder, so that could be a 200a panel if you wanted.

The feeding breaker is sized to the wire. The breaker in the sub is just a disconnect

I guess I’m confused. Do I need #2 or #3 THWN to feed 100 amps to the shop? I’m assuming I could use either. Maybe #3 would be a little cheaper? The panel in the shop is a 100 amp panel and has a 100 amp breaker and the 2nd panel is a 125 amp lug only panel. I’m currently in the process of running 3 black #4 THHN (2 hot, 1 common which will be marked white with tape) and 1 green #6 THHN to the 2nd shop panel. I know that the amp rating of the panel doesn’t really matter and it’s more about the breaker that protects the wiring. The 2nd panel is being installed mainly because I’m in the process of installing two 24K mini-splits and I’d like to run those off a panel at the back of the shop, which will also give me a little more power flexibility for the entire shop. This way I’ll have a panel at the front left corner and a panel at the rear right corner.

 

[wyliesdiesels]

So I need 2 black (hot) #2 THWN, 1 white (neutral) #4 THWN and 1 green (ground) #6 THWN?

no those sizes are all over the place. for 100a you need #3 cu (2 black 1 white) w/ #8 green for ground or #1 al with #6 green for ground.

My house main panel has a 100 amp breaker feeding the shop panel. The shop panel has a 100 amp breaker in it and I have a 100 amp breaker that will feed the 2nd sub panel in the shop. Are you saying I need to buy three 90 amp breakers? One for the main panel to feed the shop panel, one for the incoming power in the 1st shop panel and one feeding the second shop panel? My second shop panel is lug only.

wow if that existing feeder is #6, that breaker is way too large

the breakers need to match the wire gauge. so the size of breaker you buy will depend on the gauge of wire you install

 

[wyliesdiesels]

I guess I’m confused. Do I need #2 or #3 THWN to feed 100 amps to the shop? I’m assuming I could use either. Maybe #3 would be a little cheaper? The panel in the shop is a 100 amp panel and has a 100 amp breaker and the 2nd panel is a 125 amp lug only panel. I’m currently in the process of running 3 black #4 THHN (2 hot, 1 common which will be marked white with tape) and 1 green #6 THHN to the 2nd shop panel. I know that the amp rating of the panel doesn’t really matter and it’s more about the breaker that protects the wiring. The 2nd panel is being installed mainly because I’m in the process of installing two 24K mini-splits and I’d like to run those off a panel at the back of the shop, which will also give me a little more power flexibility for the entire shop. This way I’ll have a panel at the front left corner and a panel at the rear right corner.

look at an ampacity chart if youre confused

the 75° column is the one you use

 

[BillK]

How long ago was this done ? Why not just call the original electrician and ask him what they did ? I guess it was not inspected ?

 

[mike93lx]

How long ago was this done ? Why not just call the original electrician and ask him what they did ? I guess it was not inspected ?

I hope it wasn't inspected.

I wouldn't call back someone that messed up so much. He'll argue that it's fine, he does it all the time, and tell you to pound sand.

 

[RPH]

How long ago was my question. Panel looks new but incoming looks old. Is this panel a replacement for a previous panel?
It may have been wired when 3 wire feeds were allowed.

 

[BillK]

How long ago was my question. Panel looks new but incoming looks old. Is this panel a replacement for a previous panel?
It may have been wired when 3 wire feeds were allowed.

Thats what I was thinking. My detached garage built in about 1980 has three insulated feeds and one bare ground all going back to the main panel in my house. No ground rods. It was inspected and passed. I honestly cant tell you if the ground and neutral are together. I would have to pull the cover and look. Its been a long time since I did it

 

[wyliesdiesels]

How long ago was my question. Panel looks new but incoming looks old. Is this panel a replacement for a previous panel?
It may have been wired when 3 wire feeds were allowed.

huh? its not a 3-wire feed. its a 4-wire NM-b cable

 

[RPH]

huh? its not a 3-wire feed. its a 4-wire NM-b cable

Missed that. Thanks, reminds me I need more coffee.
Edit: I must have been blind at that moment!

 

[wyliesdiesels]

Thats what I was thinking. My detached garage built in about 1980 has three insulated feeds and one bare ground all going back to the main panel in my house. No ground rods. It was inspected and passed. I honestly cant tell you if the ground and neutral are together. I would have to pull the cover and look. Its been a long time since I did it

but that isnt a 3-wire feed either. a 3-wire feed has no EGC.

ground rods have always been required for detached structures so someone just skipped them...and the inspector was lousy

 

[BillK]

ground rods have always been required for detached structures so someone just skipped them...and the inspector was lousy

Interesting. I did all of the work and the inspector was actually pretty picky if I remember correctly. I am pretty sure I still have whichever code book was in use at the time. I'll have to dig it out and look.

 

[rockcrawler]

How long ago was this done ? Why not just call the original electrician and ask him what they did ? I guess it was not inspected ?

Shop build is about three years old. No way I’m calling that guy back out here after the hack job he did. The entire build process was a total nightmare. Builder was sketchy, as was everyone he used. The only ones that I think were legit, were the overhead door guys. No inspections required were I live. Of course, in hindsight, I should have hired my own inspectors to come out. Live and learn. All I can do now is move forward.

 

[mike93lx]

Shop build is about three years old. No way I’m calling that guy back out here after the hack job he did. The entire build process was a total nightmare. Builder was sketchy, as was everyone he used. The only ones that I think were legit, were the overhead door guys. No inspections required were I live. Of course, in hindsight, I should have hired my own inspectors to come out. Live and learn. All I can do now is move forward.

Finding out now is a hell of a lot better than when there is a problem. You can get this sorted out. Just keep asking questions before buying stuff

 

[acer66]

Missed that. Thanks, reminds me I need more coffee.
Edit: I must have been blind at that moment!

I know how that goes and while I am still working on the first coffee myself here I got a question.

I think to remember reading here on GJ that the EGC connecting the panel to the rods can be stranded too.

Correct?

Good luck to the OP sorting things out.

 

[mike93lx]

I know how that goes and while I am still working on the first coffee myself here I got a question.

I think to remember reading here on GJ that the EGC connecting the panel to the rods can be stranded too.

Correct?

Good luck to the OP sorting things out.

Yes, stranded is fine

 

[rockcrawler]

When I had the electrician over to help me figure out what all I needed, I told him about an issue I had with my small air compressor tripping the breaker after running for a minute. He looked at it and said there should be no reason for it to trip. I had the panel cover off so he looked around and found one of the commons was loose. He was able to wobble it around. He tried to tighten the screw but it was stripped. He moved it to another slot and tightened it down. We will see if that fixed the issue. Another “issue” created by the installer. Another reason he will never come back to my house.

 

[mike93lx]

When I had the electrician over to help me figure out what all I needed, I told him about an issue I had with my small air compressor tripping the breaker after running for a minute. He looked at it and said there should be no reason for it to trip. I had the panel cover off so he looked around and found one of the commons was loose. He was able to wobble it around. He tried to tighten the screw but it was stripped. He moved it to another slot and tightened it down. We will see if that fixed the issue. Another “issue” created by the installer. Another reason he will never come back to my house.

Did he check the rest of the screws and breakers to make sure they are tight? I'd do that if not

 

[RPH]

This just keeps getting worse. Everywhere you check another issues shows up. Looks like a total do over from wire to all connections both ends.
I always thought stranded was ok for the earth ground but here they minimum 6 gauge solid.

 

[mike93lx]

This just keeps getting worse. Everywhere you check another issues shows up. Looks like a total do over from wire to all connections both ends.
I always thought stranded was ok for the earth ground but here they minimum 6 gauge solid.

There is a written amendment requiring #6 solid?

 

[rockcrawler]

Did he check the rest of the screws and breakers to make sure they are tight? I'd do that if not

Yes

 

[rockcrawler]

So, I took a closer look at the wire coming into the shop and all I could see is that is says Superslick Elite on the jacket. I cannot see anything below that. Also, it looks to be a larger gauge wire than the 4 awg wire I’m running from panel 1 to panel 2. I’m pretty sure it is 3 awg.