Panel bonding

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royguard

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construction consultant
The 200amp main breaker panel is located on the exterior of the house. On the interior wall behind the panel in the garage is the branch circuit panel

For the garage panel. shouldn't the equipment grounds and the neutrals be isolated from each other and the bus bar not be bonded to the panel box? Or is this configuration the correct?
 
Assuming the interior panel is a subpanel to the exterior panel, then yes, the grounds and neutrals must be separated and there is no bonding allowed.

I'm not positive about this next point and I'm sure I will be corrected if wrong. If the interior panel is connected to feed-through lugs on the exterior panel, it is an extension of the main panel and therefore: combining N and G; and bonding is allowed. This would also be true if the two panels are tapped off the same service conductors.
 
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The main breaker panel outside is just that - a main breaker panel and your first over-current device. The neutral and ground wires are bonded together there. All panels down-stream of that are sub-panels. The neutrals float and the EGC's are bonded to the enclosure.
 
There is only the main breaker outside in the panel box. So in my case, the configuration for the interior panel is to have the EGC's separated from the equipment grounds, and the bus bar not bonded to the enclosure, correct?

Thank you for your help
 
As Goldstar states, any panels downstream from your service disconnect or service panel require neutral-equipment ground separation.
IF your interior panel is so designed to have two separated bars then the equipment bar would be bonded to the cabinet.
Your statement would be more correct if you clarified to say "the NEUTRAL (groundED) buss barr not bonded"
 
augie47 said:
As Goldstar states, any panels downstream from your service disconnect or service panel require neutral-equipment ground separation.
IF your interior panel is so designed to have two separated bars then the equipment bar would be bonded to the cabinet.
Your statement would be more correct if you clarified to say "the NEUTRAL (groundED) buss barr not bonded"
Click to expand...

OK, Now I'm curious for myself. Does downstream here mean a subpanel or the other conditions I specified in post 2? I'm not sure if you are saying I was incorrect.
 
Royguard, what is your relation to the electrical industry? This seems like a DYI post which is not allowed. PM me if I have misjudged this.
 
What you stated in post 2 as to a "downstream" panel being fed form sub-feed lugs, in this area is still considered a sub-panel and would require separation.
 
Coppersmith said:
OK, Now I'm curious for myself. Does downstream here mean a subpanel or the other conditions I specified in post 2? I'm not sure if you are saying I was incorrect.
Click to expand...
Considering the electrical power as flowing out of the power plant through the POCO distribution system toward the customer's loads, that direction is considered downstream.
Once the power has passed through the service disconnect onto the bus of main panel, the next panel or other device along the way to the load is called downstream. If you have two main disconnects grouped together, neither of them is downstream of the other,
 
Ok, so why would an MLO panel connected to pass-through lugs on the main be considered a sub panel. Sounds like an extension to the main to me. There's no OCPD between the two. It's the same bus basically. And if it's the same bus, why can't it be treated the same, i.e. combined N and G. Somebody have a code reference?
 
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