[brazensol]

I had a subpanel installed being fed from an existing 100a subpanel (they sit next to each other). I would like to confirm the electrician wired the ground correctly. He ran the ground from the existing subpanel's ground bar to the new subpanel's neutral bar. Also, does the aluminum wire require an anti-oxidant joint compound? The electrician told me he only uses it in a damp/wet environment.

 

[Jim Port]

The ground can land on the neutral bus in the service panel. Any downstream panels require isoLatin from the neutral.

Antioxidant paste is a good trade practice , but is not required.

 

[rjniles]

Sounds like you need a new electrician. There should be 4 wires feeding your existing sub. 2 hots, a neutral on an isolated bar and ground on a separate bar. Grounds and neutrals should not be mixed. The aluminum feeder connection should have NO-OX.

 

[brazensol]

Although I don't have much if any experience with residential electric this didn't seem right to me which is what prompted me to ask. There are four wires feeding the sub - black, red, white and ground. The two hots are wired correctly but it was the ground and neutral that had me curious and gave me some doubt. If I am understanding you guys correctly the new subpanel should be wired just like the main panel is to the existing sub?

 

[joed]

Yes. The new panel should have the neutral and ground separate and not bonded together. I guess you didn't have an inspection because it should not have passed if you did.

 

[brazensol]

Yes. The new panel should have the neutral and ground separate and not bonded together. I guess you didn't have an inspection because it should not have passed if you did.

I live in Alaska and there are no inspectors. Sad but true. You would be amazed at the things people do here...

 

[Jim Port]

Post a picture of both panels for confirmation.

 

[psgama]

Should be a 4 wire feeder. The two hots one to each bus bar, the neutral to the neutral bus and the bond to a bond bus. The neutral bus should be isolated from the bond bus. Sometimes there is a terminal screw that needs to be removed if you used a combination panel as your sub-panel.

Burndy Penetrox or similiar should have been used on the aluminum conductors, as when aluminum oxidizes, the oxide formed is non conductive. This in turn may cause additional heat stress on the connections over time.

Since its just a sub panel, it should be easy for you to turn off the breaker and apply some.