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dannt1660
Sub panel install

Hi,

For our kitchen remodel we are changing our stove/oven to gas which makes the 50amp 220/240v electric circuit available to feed a sub panel. I would like to use the original #6 wire to feed the sub panel that will have a 20amp AFCI breaker for the bedroom and a double 15 amp breaker for the dishwasher and disposal. Will this work with a 70amp sub panel with two breaker positions? Anything I should be aware of? I live in Northern California.

Thanks,

Dann

kentvw
Re: Sub panel install

Tell me about the number 6;
Copper? Aluminum?

How many conductors in what I assume is cable feeding the old range?

3 or 4?

dannt1660
Re: Sub panel install

It seems to be aluminum 3 wire with ground (also aluminum)

Dann

kentvw
Re: Sub panel install

I would say it is doable.

Here are a few things to chew on.

In your sub panel you will need to isolate your ground and neutral, which is going to mean you need to buy a ground bar kit and make sure your existing neutral bar is not screwed or strapped to the panel can. …….. the 50 amp breaker in the main panel will serve as overcurrent protection for the wire and the panel. You do not need another main breaker in your sub panel.

I would also take a look at the electrical rating of the disposer and dishwasher to determine if a 15 a breaker is large enough for the load.

This is per National Electrical Code requirements. You may want to check with your local requirements.

dannt1660
Re: Sub panel install

In your sub panel you will need to isolate your ground and neutral, which is going to mean you need to buy a ground bar kit and make sure your existing neutral bar is not screwed or strapped to the panel can. …….

How can I tell if the neutral is screwed to the panel can? If so, what would happen? Would the ground appear missing since it is tied to the neutral?

Thanks,

Dann

kentvw
Re: Sub panel install

"From the factory" the neutral bar is not usually bonded to the can. A strap or green screw is usually provided for that purpose.

You should be able to see this screw or a metal strap going from a screwed down location on the can to one of the neutral bar lugs if it is bonded.

You never want to intentionally have current flowing on the ground wire. If you have an electrical connection between the ground and neutral in your sub panel then any neutral current on the sub panel circuits will flow back to your main panel on both the neutral wire and ground wire, they will share that load on parallel paths.

You do not want that to happen. You only want the neutral and ground bonded together in one place at your main service.

dannt1660
Re: Sub panel install
kentvw wrote:

You never want to intentionally have current flowing on the ground wire. If you have an electrical connection between the ground and neutral in your sub panel then any neutral current on the sub panel circuits will flow back to your main panel on both the neutral wire and ground wire, they will share that load on parallel paths.

You do not want that to happen. You only want the neutral and ground bonded together in one place at your main service.

I have wired the previous as described. Sub panel does not have the ground bar bonded to the neutral. Both of the 15amp circuits show no ground when I put a tester in the receptacle. I did put GFCI receptacles in for the two circuits as both are near water.

Any ideas?

Dann

Ernie_Fergler
Re: Sub panel install

Did you install a ground bar kit in the sub panel?
You need to have two separate hot leads, [a red & black], the white neutral and a bare ground wire leading into the sub panel from the main.

dannt1660
Re: Sub panel install

Yes to:

Ground bar kit

Black to hot bus bar 1
Red to hot bus bar 2
White to neutral bus bar
Ground to ground bar

Could the GFCI's be part of the issue? I did check inside the Main panel to see if the 50amp was wired correctly too (Yep). New home runs were run for each of the 15amp circuits. I have not put the 20amp AFCI breaker in as I want to solve this first.

Hmmm...

Ernie_Fergler
Re: Sub panel install

Got to think about this one....

dannt1660
Re: Sub panel install

Well... after further investigation it seems that the ground was never attached at the main breaker panel. Seems someone did not attach it when this house was built in 1971. What possible danger could this have caused since an electric stove was always connected?

Thanks for all your insight and help on this one. When in doubt look further (carefully!!!:cool: ).

Dann

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