Nuetrals in a panel

[garrisonm1]

Say you have a double panel ckt 1-42 and 43-84. In the right side I have ckt 34 coming in, now you have to take the ungrounded conductor through the nipple to the panel on the left to take it to the proper breaker but does the nuetral and ground have to go the the left panel or can they stay on the right side and get landed on the bars.

 

[iwire]

Re: Nuetrals in a panel

Take a look at 2002 300.3(B) IMO you have to run the grounded conductor through the same nipple as the ungrounded conductor.

 

[goldstar]

Re: Nuetrals in a panel

Electrically speaking the neutrals are the same. However, you cannot use the breaker panel as a raceway.

If the breaker panels are set up as service equipment where both have a main you should have had the service entrance conductors piped into a trough, used Polaris insulated bugs, and tapped off into the top of each breaker panel's main breaker.

If you set the second panel up as a sub-panel and nippled from one panel to the other you certainly cannot run through the same nipple as the feeder conductors. Also, you'll have to split the EGC's and neutrals. Quite frankly, I've never seen (2) 42 circuit panels set up this way.

I'd be interested to know how you make out with this.

 

[iwire]

Re: Nuetrals in a panel

Goldstar, We install a lot of Double tub and even some triple tub panels in office spaces, so many dedicated circuits with only a few amps of load each.

One 225 amp feed into the first feed through panel then into the second, we use a two 4" nipples one at the top and one at the bottom, one for the feeders and one for doing just what garrisonm1 needed to do.

Triple tubs that I have done got 400 amp feeds, you end up with circuits marked 1 to 126

 

[bphgravity]

Re: Nuetrals in a panel

312.8 does say that enclosures for OCD shall not be used as a raceway UNLESSS adequate space is provided. The section specifies allowed percentage fill for this purpose.

 

[goldstar]

Re: Nuetrals in a panel

Iwire,

Another learning experience for me. I'm getting too old to learn new stuff !!!

Do each of the panels have their own main breaker or are the 2nd and 3rd panels main lug ? I wasn't thinking of a commercial application when I answered this question. I guess if you gang 3 tubs together it's considered one assembly and as such one load center. If they're main lug how do you buss from one panel to the next ? Do they have double lugs ?

 

[iwire]

Re: Nuetrals in a panel

Goldstar, If there is a main it would be in the first panel, many times no main. The overcurrent is provided at the start of the feeder so if you have a 400 amp feeder all the panels must be rated at 400 amps.

Some interiors come with double barrel lugs, but this can lead to tight spacing between conductors, more often one set of lugs at the top and bottom, so if your the feeder drops in from the top you feed the next panel from the bottom.

This is a great set up it gets you 84 or 126 circuits with one feeder.

 

[goldstar]

Re: Nuetrals in a panel

Iwire,

Thanks for the info. Are the panels you use panelboard breaker panels (i.e bolt-on breakers) or std. plug-in breakers ? Must be some big lugs too !!! Just curious.

[ March 28, 2003, 06:11 PM: Message edited by: goldstar ]

 

[iwire]

Re: Nuetrals in a panel

Yes, bolt on breakers, here is a typical lug for a 400 amp panel with double lugs for the next panel.

It is about 1 1/2" wide 4 1/2" long 3" tall

 

[bob_hartman]

Re: Nuetrals in a panel

Goldstar, can you quote the section that dis-allows running sub-panel feeders and branch circuit conductors through the same nipple? I have seen this done many times, and always thought it was legal. Thanks

 

[goldstar]

Re: Nuetrals in a panel

Bob,

Re : branch circuit wires in the same nipple or raceway as feeders

230.7 is the only one I can find at the moment but I could be off base on this. I was taught that this was taboo. If anyone knows differently please post it here. I would be interested in knowing if I am correct or not and why. This may just be something I was taught as an apprentice but never given the reason why. It just seemed logical to me.

 

[roger]

Re: Nuetrals in a panel

Goldstar, your reference to 230.7 is correct in that it does prohibit any other conductors besides service conductors from being in a common raceway.

A fused feeder can be in, or have other fused conductors in a common raceway.

Roger

 

[renosteinke]

Re: Nuetrals in a panel

FWIW-
Had my holiday interrupted last Thanksgiving when an improperly installed "two-gang" panel. What had happened was that there had been no neutral wire run; the neutral bar in the second panel had been bonded to the case, and any imbalance drained through the case to the ground bus in the neighboring panel. Worked fine, untill 30 years' worth of vibration, rust, etc. opened the path.
After running maybe 6 ft. of feeder-size wire to the neutral bus, and removing the bonding screw, and connecting the ground busses with #8, all is well; the IT guys immediately reported the clearing up of several gremlins in their network.
Lesson: There is only one main panel. Everything else, even if it's just as big, and right next to it, should be treated as a sub-panel.