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AssuredElectrical
AssuredElectrical, Master Electrician
Category: Electrical
Satisfied Customers: 4241
Experience:  Contractor-42+ Years in the ElectricalTrade
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Can two single phase 220 volt circuits share the ground?

This answer was rated:

Can two single phase 220 volt circuits share the ground?

AssuredElectrical :

Welcome. My name is XXXXX XXXXX would be glad to assist.

AssuredElectrical :

So, are you running separate cables or conduits to the individual disconnects for the AC?

AssuredElectrical :

Or is there a common disconnect with 2 separate breakers or cutoffs?

AssuredElectrical :

Trying to determine how you have separate feeds and only a common ground available

Customer:

I am planning to run a single conduit from the panel about 75 ft to the a junction box and I will branch off there to two separate disconnects.

AssuredElectrical :

What size wire to the junction boxes? How do you plan on protection for the tap offs the junction box?

AssuredElectrical :

What is the amperage of these 2 units?

AssuredElectrical :

Will they be totally separate circuits?

Customer:

There will be two 30 amp two pole breakers in the panel and #8 wire run to the junction box for the two disconnects but should I run two separate grounds from the panel or can I run one and branch off it two the disconnects at the junction box? They are two separate circuits.

AssuredElectrical :

Ok, thanks for info.

AssuredElectrical :

What you need is separate ground wires along with the power feeders. If you had a single one and split at the junction box, if someone worked on one unit and disconnected the ground at the panel, the other unit would be unsafe. Separate ground wires insure each unit is grounded at all times.

AssuredElectrical :

With the #8 and 30 amps, you only need a #10 for the grounds

Customer:

So two separate #10 ground wires from the panel to the disconnects would be fine with the #8 power feeder wires then?

AssuredElectrical :

That is correct

Customer:

Okay thanks for your help

AssuredElectrical :

3-60 amps is a #10 copper ground wire

AssuredElectrical :

Sorry typo, 30-60 amps is #10 ground wire

AssuredElectrical :

You are very welcome. Glad to be of service.

Customer:

Do you think I can use 3/4" emt conduit or should I use 1"?

AssuredElectrical :

Code allows the 3/4", but always look at the piping and bends to be sure it looks like an easy pull. That is right at the limit of the conduit.

AssuredElectrical :

If I only had a minimum bend, say 45 degrees, I would use the 3/4" personally

AssuredElectrical :

3/4" can have 6-- #8 wires THHN

Customer:

I'll probably have two 90 degree bends so I'm thinking I'd be better off with the 1". Would you agree?

AssuredElectrical :

2- 90's, I would prefer the 1" myself also, 90 elbows can get cumbersome sometimes in the run

Customer:

Okay thanks again.

AssuredElectrical :

You are very welcome.

AssuredElectrical and 3 other Electrical Specialists are ready to help you

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