01:03PM | 09/12/03
Member Since: 06/06/03
1248 lifetime posts
Howdy electrical gurus!

I've got a GE subpanel attached to a GE panel. The subpanel was installed several years ago by professional electricians. (They recognized that the panel is crowded and added it, moving a couple circuits in the process. They used blue wires in order to tell which ones were moved.)

So, that said, is there anything I need to know about adding a new circuit to the subpanel? The cable must be fed from the house through the main panel to get to the subpanel. Should the sheathed electrical cable sheathing be removed all the way through, or not? (If so, I'd think it would be crowded, but if not, the black & white wires will just add to the confusion of what's there.) Anything I oughta know here?

Thanks in advance!
-k. in Colorado


02:51AM | 09/13/03
Member Since: 11/05/01
101 lifetime posts
Yes. Electricity kills. Even if you turn off your main your panel may still likely have power to it. Proceed with caution. Better yet hire an electrician.


01:09PM | 09/13/03
Member Since: 06/06/03
1248 lifetime posts
Thanks Scott,

My panel is nice from the standpoint that there's a main switch with a single (150-amp) breaker on a detached garage. So that leaves the panel (on the house) TOTALLY dead.

I've worked around panels before in other houses where the incoming mains could never be shut off (a more typical arrangement). I have some prior experience in both farm & knob-and-tube wiring--so have been around conditions far more unsafe than what I've got now

Anyway, I have tried to learn as much about the NEC as I can and live by the code. I've corrected a lot of problems along the way (things like unconnected ground wires in switch boxes). I'd love to always hire an electrician--I think they earn a fair wage. But I CANNOT afford the overhead of the "estimators" and contractors that come to the house once--and somehow $hundreds (or even thousands) seem to be added for the privilege.

So, unfortunately, I'm left to have to do some of the more minor work myself.

And you're right, of first, always!

Thanks for taking the time to respond.


06:23AM | 09/14/03
Member Since: 06/06/03
1248 lifetime posts
So, all that said, if anyone can help with the original question I'd still appreciate constructive feedback--or the citing of any appropriate sections from the NEC about the subject.

Thanks again all!

[This message has been edited by k2 (edited September 14, 2003).]

Tom O

02:06PM | 09/15/03
Member Since: 09/17/02
487 lifetime posts
You should remove the outer jacket from the cable so it does not take up too much space. That in itself is not a code requirement.

There is a limit to how much of the availble space in a panel can be taken up by cables & wires. See 312.8

Another issue could be conduit fill. Is there a conduit nipple between the two panels that all the wires run through? If so, see table 1 to chapter nine and look to see if note 4 applies to your installation.



04:51PM | 09/15/03
Member Since: 06/06/03
1248 lifetime posts
Hey there Tom,

Thanks for the response, and the NEC references. I just think it's great that you folks can cite the code--whether it's through memory or looking it up! (For me, it's a fishing expedition at the local library, so having the references helps a lot!)

Yes there's definitely a conduit nipple between the panels. And it really doesn't take too many wires to start crowding that thing--especially since it's got a downward bend to it. So removing sheathing does make sense.

The electricians moved 2 breakers to the subpanel to reduce the crowding. There are also a couple more superfluous circuits that could be taken out altogether. I took out one old unused 240v circuit--nice to have that heavy cable out of there--even though it leaves a large gap on the panel (I covered this with snap-in plugs).

It's all something that just 'sort of happened' over 20 years, to get to the point that it is today. One of the worst offenders was an old hot-tub install (20 yrs ago)--those guys just did "whatever" to put it in. Very glad to have the hot-tub gone (you should've seen what they did to the gas line and its venting!, it was UGLY!)

Thanks much for your response! I very much appreciate it.


08:42PM | 09/16/03
Member Since: 05/11/03
64 lifetime posts
To add a little information. As long as the nipple is 24" or less there is no limit to the number of wires that can be run through it. If it is longer then the NEC has strict limitations on the number of wires. Mr. Electric


04:14AM | 09/17/03
Member Since: 06/06/03
1248 lifetime posts
Thank you, Sir! The panels are very close, and as such a short (maybe 3") nipple is used. There's still room to squeeze some more wiring in there

Tom O

12:52PM | 09/17/03
Member Since: 09/17/02
487 lifetime posts
There is a limit to how many conductors can be placed in a short nipple. Note 4 to Table 1 of Chapter 9 limits the fill of short nipples (24" or less) to 60%.

Conductors in these short nipples do not need their ampacities derated.


03:18PM | 09/17/03
Member Since: 06/06/03
1248 lifetime posts
Thanks again for the info, Tom! I still need to get down to the library and look at that NEC table. I have been soooooo darn busy; today I was doing plumbing and it just wore me out!

Thanks again Tom!

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