120volt sub panel.

[arnettda]

Can I have a sub panel that is only 120volt. Feed by two #6s. Will have 4 breakers in sub panel. I would need to drive ground rods? This is existing fuse panel and it needs to be replaced. There is no third wire for ground.

 

[infinity]

You've mentioned ground rods is this in a separate structure?

 

[Ponchik]

If you are installing the new feeder why not install a 4 wire system?

I am sure you know that you can't use the ground rod in place of the EGC.

And as mentioned earlier if it a separate structure it needs a grounding electrode.

 

[arnettda]

You've mentioned ground rods is this in a separate structure?

Yes

 

[kwired]

We need more info.

Is this a separate building fed from another building? If so separate equipment grounding from grounded conductor is required. If reusing a feed that did not have an equipment grounding conductor there may be exceptions that will allow you to keep it that way - it likely had to be code compliant at one time or it will never qualify for the exceptions.

Is it feed from service? If so then you do connect the grounded conductor to a grounding electrode - it is a two wire service - not real common, but possible.

Separate building needs grounding electrode in most all cases - some exceptions for building fed by individual branch circuit or multiwire branch circuit.

 

[arnettda]

We need more info.

Is this a separate building fed from another building? If so separate equipment grounding from grounded conductor is required. If reusing a feed that did not have an equipment grounding conductor there may be exceptions that will allow you to keep it that way - it likely had to be code compliant at one time or it will never qualify for the exceptions.

Is it feed from service? If so then you do connect the grounded conductor to a grounding electrode - it is a two wire service - not real common, but possible.

Separate building needs grounding electrode in most all cases - some exceptions for building fed by individual branch circuit or multiwire branch circuit.

Yes it is a seperate building fed from other building. My state has a seperate elec code that says if it was legal when it was installed you can replace but not modify it which I am doing so I believe I am legal. No ground rods are present now so would adding them make it a better installation? I have also never installed a 120 volt sub panel.

 

[Steviechia2]

Watch your load. Without the other ungrounded conductor to balance the load this could be easily overloaded

 

[infinity]

Watch your load. Without the other ungrounded conductor to balance the load this could be easily overloaded

How can you have an unbalanced overload a 2-wire circuit?

 

[Steviechia2]

How can you have an unbalanced overload a 2-wire circuit?

I meant to say you can go above the rated capacity of the grounded conductor. :ashamed1:

 

[infinity]

I meant to say you can go above the rated capacity of the grounded conductor. :ashamed1:

So you mean he could overload the branch circuit neutral if he tried to install a MWBC on the 120 volt panel. Good point.

 

[kwired]

I meant to say you can go above the rated capacity of the grounded conductor. :ashamed1:

Only if you attempt to install multiwire branch circuits. And this overloading would only apply to the branch circuits. The feeder still has same load on grounded and ungrounded no matter what. If the conductors are same size (no real reason for them not to be) they both carry same current and are both overloaded at same current level.