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Steelhead 02-01-2009 12:39 PM

Ground Bar
 
If you add an additional ground bar to the service panel (main disconnect) are you required to add a bonding jumper from the additional grounding bar to the ground/neutral bus or is the connection of the bar to the cabinet sufficient?

dSilanskas 02-01-2009 01:38 PM

Quote:

Originally Posted by Steelhead (Post 223141)
If you add an additional ground bar to the service panel (main disconnect) are you required to add a bonding jumper from the additional grounding bar to the ground/neutral bus or is the connection of the bar to the cabinet sufficient?



The connection to the cabinet is sufficient

jamiedolan 02-01-2009 02:31 PM

Quote:

Originally Posted by dSilanskas (Post 223161)
The connection to the cabinet is sufficient

The Machine screws that come with the bar are all that you need correct? Nothing special like the green ground screw right?

Jamie

Stubbie 02-01-2009 03:32 PM

Quote:

Originally Posted by jamiedolan (Post 223188)
The Machine screws that come with the bar are all that you need correct? Nothing special like the green ground screw right?

Jamie

Correct, though you need to be careful of a proper ground if you are not installing the ground bar in the factory predrilled holes.

Steelhead 02-01-2009 07:45 PM

Quote:

Originally Posted by Stubbie (Post 223222)
Correct, though you need to be careful of a proper ground if you are not installing the ground bar in the factory predrilled holes.

I will scrape/sand off the paint to help ensure a good bond when installing grounding lugs in panels. Would this be what you're talking about when installing grounding bars where there isn't factory holes?

KE2KB 02-01-2009 08:49 PM

I assume that you are talking about a GROUND bar, that will be used only for GROUND conductors, not NEUTRAL conductors.
If the bar is to have both ground AND neutral conductors connected, it MUST be bonded to the main ground/neutral bar, which is bonded to the neutral conductor of the SE.

FW

Steelhead 02-01-2009 08:56 PM

Yes, I'm talking about a ground bar only.

KE2KB 02-01-2009 09:04 PM

Quote:

Originally Posted by Steelhead (Post 223372)
Yes, I'm talking about a ground bar only.

OK. Had to bring it up though<g>

FW

Scuba_Dave 02-01-2009 09:12 PM

If you were attaching neutrals, what size wire would you need to connect the new bar to the existing bar?

Steelhead 02-01-2009 09:20 PM

Quote:

Originally Posted by Scuba_Dave (Post 223382)
If you were attaching neutrals, what size wire would you need to connect the new bar to the existing bar?

I was wondering the same thing. I wonder if you can legally do this anyway?

KE2KB 02-01-2009 10:08 PM

Quote:

Originally Posted by Steelhead (Post 223388)
I was wondering the same thing. I wonder if you can legally do this anyway?

Legally do what? Connect both neutrals and grounds on the same bus?
Sure you can; if it's in a MAIN SE panel, and not a sub, AND if your buses are bonded to the neutral SE conductor.

I don't know what size wire is needed for bonding two neutral buses. The one in my panel uses a bar, not a wire to bond the two buses.
It should be dependent on the total capacity of the panel, and/or the capacity of the bus.

FW

Scuba_Dave 02-01-2009 10:09 PM

I think it would be the safest thing to do, since somebody down the road might use it for neutrals

Stubbie 02-01-2009 11:14 PM

Wait a minute guys. If you add a 'ground bar' to the main panel (service equipment) that is not on insulated standoffs and is mounted to the metal of the can you can only connect grounds to it.... NO neutrals. You cannot use the metal of the can for a neutral return path nor can you use a jumper between the added ground bar and the factory neutral. This will allow for a parallel return of neutral current if you did. You also must use a mounting connection that allows at least 2 threads in contact with the metal thickness as mandated in NEC 250.8 if you do not use factory mounting holes.

KE2KB 02-02-2009 06:12 AM

Quote:

Originally Posted by Stubbie (Post 223479)
Wait a minute guys. If you add a 'ground bar' to the main panel (service equipment) that is not on insulated standoffs and is mounted to the metal of the can you can only connect grounds to it.... NO neutrals. You cannot use the metal of the can for a neutral return path nor can you use a jumper between the added ground bar and the factory neutral. This will allow for a parallel return of neutral current if you did. You also must use a mounting connection that allows at least 2 threads in contact with the metal thickness as mandated in NEC 250.8 if you do not use factory mounting holes.

So the factory ground/neutral bar(s) are insulated from the box?
I didn't notice that when I was working in my SE panel.
There is plastic at the ends, so I suppose it is insulated, and there is a bar connecting the two. This is factory installed for grounds and neutrals.

FW

KE2KB 02-02-2009 06:17 AM

Quote:

Originally Posted by Scuba_Dave (Post 223423)
I think it would be the safest thing to do, since somebody down the road might use it for neutrals

I agree. A lot of DIY'ers won't ever notice that the bus isn't configured for neutrals.

A word of caution here: When adding a bonding conductor between ground/neutral buses, you need to be extremely careful not to get the large conductor near the live SE conductors. Even with the main breaker shut off, there are still exposed live parts at the lugs.
It's too easy to be pulling wires in that area and have one get across the live parts, causing either electrocution, or an arc-flash.

I would run the bonding wire at the opposite end, as far from the main breakers as possible.
You should be able to position the large lugs for the bonding wire at any point on the ground/neutral buses.

FW


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