Bundling in a panel board

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RSW

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If you have more than 30 current carring conductors bundled (ty-wrapped in lengths over 24") in a panel board, do you have to derate? As near I as I can tell in 312.8 you can use a panel board as a raceway, but that doesn't mean that it is classified as one. In article 366.22 (B), and article 376.22 reference 30 current carring conductors as a cut off to where you have to start derating, and article 310.15(B)(2) refrences the 24". I think it boils down to what a panel board is classified as. Dose any one have any thoughts?
 
RSW said:
If you have more than 30 current carring conductors bundled (ty-wrapped in lengths over 24") in a panel board, do you have to derate? As near I as I can tell in 312.8 you can use a panel board as a raceway, but that doesn't mean that it is classified as one. In article 366.22 (B), and article 376.22 reference 30 current carring conductors as a cut off to where you have to start derating, and article 310.15(B)(2) refrences the 24". I think it boils down to what a panel board is classified as. Dose any one have any thoughts?
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I also say no. The derating only applies to raceways and cable.
 
mcdowellb,
The derating only applies to raceways and cable
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Really???
(a) More Than Three Current-Carrying Conductors in a Raceway or Cable. Where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables are stacked or bundled longer than 600 mm (24 in.) without maintaining spacing and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a). Each current-carrying conductor of a paralleled set of conductors shall be counted as a current-carrying conductor.
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That being said, the exception cited by Bryan, eliminates the requirement to use the reducded conductor ampacity that is the result of the application of 310.15(B)(2).
Don
 
Thanks for clearing that up Don...who was it that said " The code doesn't always say what you think it says"?
 
I can't help but wonder why wires need to be tie-wrapped in panels to begin with. I have no trouble keeping them neat without wraps. If they're really needed (for stranded wire, say) nobody says they have to be so tight.
 
celtic said:
Who says they "need to be"?
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You couldn't see my tongue in my cheek?

It's just something I never do. When I dress a panel, the wires seem to stay in place without help.

Feeder first, EGC's second, neutrals third, hots last. Why tie?

KwPanels2.jpg
 
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LarryFine said:
You couldn't see my tongue in my cheek?

It's just something I never do. When I dress a panel, the wires seem to stay in place without help.

Feeder first, EGC's second, neutrals third, hots last. Why tie?

KwPanels2.jpg
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Wow Larry, that's excellent work. Time well spent.
 
McDowellb said:
Wow Larry, that's excellent work. Time well spent.
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Thanx!

For what it's worth, I did not take extra care or time in these panels for the pictures.

It takes no more time to dress them neatly than sloppily; in fact, maybe less.
 
LarryFine said:
Thanx!

For what it's worth, I did not take extra care or time in these panels for the pictures.

It takes no more time to dress them neatly than sloppily; in fact, maybe less.
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I especially like the order you said you terminate the conductors. I've always done hots, neutral then eq. grounds.
 
LarryFine said:
You couldn't see my tongue in my cheek?

It's just something I never do. When I dress a panel, the wires seem to stay in place without help.

Feeder first, EGC's second, neutrals third, hots last. Why tie?

KwPanels2.jpg
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This conductor order is important for safety reasons. You should allways be grounded before being energized with no ground hooked up. Larry do you always use ser cable for your services? Not trying to critisize but dont forget to tape them white conductors on your ocp black.
 
NICK D said:
This conductor order is important for safety reasons. You should allways be grounded before being energized with no ground hooked up.
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True. Now that I think about it, I hook up everything that way, even light fixtures: green, white, black.
Larry do you always use ser cable for your services?
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Yes, when the main disconnect isn't in the panel. Look again.
Not trying to critisize but dont forget to tape them white conductors on your ocp black.
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If you look more carefully, you can see that they have been colored blue. They're faded a bit at the ends from handling, but they're nowhere as pale as they appear in the pic.


By the way, I dislike using tape for recoloring entire conductors (except phase marking). I do it when I must, but I prefer ink or paint.
 
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don_resqcapt19 said:
Nick,
NICK D said:
This conductor order is important for safety reasons.
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Not really as you should never be hooking up conductors to an energized point.
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While that's true, it's still one of the best habits for electricians to develop.
 
LOL

I can see the homeowner dashing out of the house yelling, "FIRE"! Not to say you'll hook up an energized overhead service (temp power to occupied home) this way: Hot-Hot-N :)
 
I hate to bring this show and tell back towards the OP but...
Wink
I'm curious about the application of 376.22. My first question is how often is this enforced? I don't think I've seen it on a job. Secondly, and more importantly, how would you go about applying 310.15(B)(2)(a)? Is 376.22 saying that if I have 30 current carrying conductors no problem but if I have 31 I must use 40% ampacity? That seems a little crazy. Do you start from the top of the table instead? Maybe 31-33 are @ 80% 34-36 @ 70% and so on?

Sorry. tried the wink icon... didn't work.
 
It is possible that someone may energize a circuit while you are working on it. Larry I just had to put my glasses on. Do you ever use ser cable on a service?
 
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