Another Sub Panel Question

[jbbies]

Ok I am in the middle of installing a 100A Square D Hom subpanel in my garage. It is going to be next to my main panel.

Local code says I can use #2 Alum. wiring for the 100A. I have been reading and it seems there is some debate. I have heard main panel breaker can be 100A other say 90A

Next Question.
I have one copper wire leading into a bus bar on the side of the panel but no other grounds are tied to it.

the neutral bus bar in the panel has both copper and common connected to same one.

I know the new common going to the sub panel ties to the neutral bus bar.

Does the Copper need to be tied into the neutral bar or the bar on the side with the one copper ground to it?

am I making sense?

 

[Alchymist]

Ok I am in the middle of installing a 100A Square D Hom subpanel in my garage. It is going to be next to my main panel.

Local code says I can use #2 Alum. wiring for the 100A. I have been reading and it seems there is some debate. I have heard main panel breaker can be 100A other say 90A
If you are only running a few feet to the subpanel, I'd spring for copper.
Next Question.
I have one copper wire leading into a bus bar on the side of the panel but no other grounds are tied to it.

the neutral bus bar in the panel has both copper and common connected to same one.

I know the new common going to the sub panel ties to the neutral bus bar.

Does the Copper need to be tied into the neutral bar or the bar on the side with the one copper ground to it?

Doesn't matter in the existing panel, you need 4 wires to the sub panel, 2 hot, neutral and ground. In the sub panel the neutral and ground bars must be separated, and all grounds in the sub panel must land on the ground bar, and all neutrals on the neutral bar.

am I making sense?

...............

 

[jbbies]

Yep. And the way I understand it is the Sub is not bonded so all wiring from it needs to be on its dedicated side unlike the main. IE grounds to grounds and neutrals to neutrals correct?

I live a ways from anywhere and copper was not currently available at the size I needed, it had to be special order and ended up being more than I wanted to spend.

 

[pattenp]

#2 AL is good for 100A when used for 3 wire service-entrance conductors (meter-base to main-panel), 2011 NEC Table 310.15(B)(7). When used as a branch circuit/feeder #2 AL is good to 90A, 2011 NEC Table 310.15(B)(16) 75C column. #1 AL is 100A.

 

[Alchymist]

I know the new common going to the sub panel ties to the neutral bus bar.

There is no "common" wire - there are only hot, neutral, and ground, more properly termed EGC - Equipment Grounding Conductor. As I stated above -

"you need 4 wires to the sub panel, 2 hot, neutral and ground. In the sub panel the neutral and ground bars must be separated, and all grounds in the sub panel must land on the ground bar, and all neutrals on the neutral bar:.

 

[Alchymist]

I live a ways from anywhere and copper was not currently available at the size I needed, it had to be special order and ended up being more than I wanted to spend.

So where do you live? I can't visualize being far enough away from an electrical supply house that single conductor copper is not available. You did say your sub panel would be next to your main, did you not? While copper is expensive, the few feet needed between panels would be relatively inexpensive.

 

[805gregg]

Hook it up then get an electrician to look at it. I wired the same subpanel in my garage for a 220 compressor. When my electrcian looked at it, he said the way it was grounded, I couls electrocute my wife at the washer in the garage. Do the work yourself but have a licensed guy look at it.