Sub panel question

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Eventh

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I am installing a sub panel next to the main in order to have more breakers. In the main panel, the neutrals and grounds are on the same buss. No ground buss. So I would think that I should only run the neutral from the main to the sub and no extra ground wire. Would that be correct? And also the neutral buss bars in the sub would float from the case.
 
Neutrals & equipment grounds would only be on a common buss in the service panel itself.
Any other panel fed by the service panel (ie: a subpanel) would need the neutrals and equipment grounds separated with the neutrals "floating"
 
augie47 said:
Neutrals & equipment grounds would only be on a common buss in the service panel itself.
Any other panel fed by the service panel (ie: a subpanel) would need the neutrals and equipment grounds separated with the neutrals "floating"
Click to expand...

So I need to run a neutral from the main panel (of course) and also a ground? I did buy a ground buss for the sub panel but it seems redundant since the ground and neutral are on the same buss in the main. So I will install a ground bus in the sub for the extra circuits and that ground buss is also connected to the neutral/ground buss in the main. Correct? Want to make sure it's to code...
 
augie47 said:
Neutrals & equipment grounds would only be on a common buss in the service panel itself.
Any other panel fed by the service panel (ie: a subpanel) would need the neutrals and equipment grounds separated with the neutrals "floating"
Click to expand...

Agree. You need to provide both a neutral and equipment ground in the feeder to the sub panel, not just the neutral as proposed in the original question.
 
Sub

Sub

Okay thanks. I don't think any new main panels that I have seen have combined neutral and ground busses so this is why I was not sure. Seems odd and I don't really like it LOL!
 
Eventh said:
Okay thanks. I don't think any new main panels that I have seen have combined neutral and ground busses so this is why I was not sure. Seems odd and I don't really like it LOL!
Click to expand...

You've never seen a panel with buses on each side with a bar tying them together and a bonding screw or jumper connected to bond the enclosure?
 
Eventh said:
Okay thanks. I don't think any new main panels that I have seen have combined neutral and ground busses so this is why I was not sure. Seems odd and I don't really like it LOL!
Click to expand...

It can make you scratch your head at first, but at the main panel where the service disconnect is...is where this bond and connection to the grounding electrode system are to occur. If it is a screw or bond between or neutrals and grounds all intermixed makes no difference, but at the service panel only.

In these mess panels, there should still be (2) conductors max per terminal.
 
Yes but

Yes but

Little Bill said:
You've never seen a panel with buses on each side with a bar tying them together and a bonding screw or jumper connected to bond the enclosure?
Click to expand...

The main panel has the neutral and ground buss bar together. So there are ground wires from the circuits and neutral wires on the same bus bar.
 
Eventh said:
The main panel has the neutral and ground buss bar together. So there are ground wires from the circuits and neutral wires on the same bus bar.
Click to expand...
Which is fine however, becarefull of putting more than one conductor in each hole, read 110.14(A) and 408.41

Roger
 
Something like this?

Something like this?

Eventh said:
The main panel has the neutral and ground buss bar together. So there are ground wires from the circuits and neutral wires on the same bus bar.
Click to expand...

Here's a picture of the main buss and the sub that will be installed. Sup is powered from a 60 amp bkr.
 

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Have you consulted with a local EC to help you?
Two wires in one hole is not necessarily the problem, it is more about what wires.

Even though your profile says you are an engineer it's obvious that this is outside your expertise and you should consult with a local EC to help you.

Roger
 
Eventh said:
To many wires on one post?
Click to expand...

The NEC allows two EGCs per terminal IF the bar is rated for it.
But you must never land two neutrals under one screw. That risks inadvertently disconnecting another neutral in addition to the one you may be working with, and since it carries normal current the neutral is also expected to be more a more reliable connection.
 
So..

So..

GoldDigger said:
The NEC allows two EGCs per terminal IF the bar is rated for it.
But you must never land two neutrals under one screw. That risks inadvertently disconnecting another neutral in addition to the one you may be working with, and since it carries normal current the neutral is also expected to be more a more reliable connection.
Click to expand...

But the general layout in the picture would be correct?
 
roger said:
Have you consulted with a local EC to help you?
Two wires in one hole is not necessarily the problem, it is more about what wires.

Even though your profile says you are an engineer it's obvious that this is outside your expertise and you should consult with a local EC to help you.

Roger
Click to expand...
I see what you are saying but don't take the simple DWG as the exact wire schematic. It's just for reference. I know that you are not supposed to put more than two wires on a post and the neutral and ground wires cannot be mixed on the same post. I probably should have stated that when I posted the picture.
 
Eventh said:
I see what you are saying but don't take the simple DWG as the exact wire schematic. It's just for reference. I know that you are not supposed to put more than two wires on a post and the neutral and ground wires cannot be mixed on the same post. I probably should have stated that when I posted the picture.
Click to expand...

What are you referring to when you say "post"?

In your pictures. the main panel is fine with neutrals & grounds on the same bus but in your subpanel they must be separate with the neutral not bonded to the can/enclosure.
 
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