bundlig over 24"

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jimalone

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i have a problem i am not sure of, would like to know if i am correct.
the circuit capacity of 10 mc cables, each cable has 2 12thhn current carrying copper wires, coming of breakers having 75 degree termination for lighting load,(bundled over 24") i figured 20 conductors at 50% would be 15 amps. am i correct or do i have everyone confused?
 
Re: bundlig over 24"

Jim is this a question on a test?

If it is I would mark it as incorrect.

You should read the exceptions for derating.
 
Re: bundlig over 24"

no, just some guys trying to trick each other, i will go back and refigure got answer 2002 book table 310-16
 
Re: bundlig over 24"

Originally posted by jimalone:
no, just some guys trying to trick each other, i will go back and refigure got answer 2002 book table 310-16
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OK

Take a look at the exception 5 to 310.15(B)(2).
 
Re: bundlig over 24"

Bob, Yur da man. :cool:

Edit: This is weird, check out how many posts are reported for this topic on the NEC forum list

Edit: I knew that would happen. It's correct now.

[ February 16, 2005, 05:34 PM: Message edited by: physis ]
 
Re: bundlig over 24"

sorry about that. my book is 1999 and exceptions only go to 4. i got answer from 310-15 b 2 a adjustment factors.. thats what happens when you get old and retire. (my adjustment factor goes to hell also)
 
Re: bundlig over 24"

That makes sense as Excepton 5 went in for 2002.

The reaon I figured this was a test question was it fits exception 5 perfectly.

Exception No. 5: Adjustment factors shall not apply to Type AC cable or to Type MC cable without an overall outer jacket under the following conditions:

(a)Each cable has not more than three current-carrying conductors.

(b)The conductors are 12 AWG copper.

(c)Not more than 20 current-carrying conductors are bundled, stacked, or supported on ?bridle rings.?

A 60 percent adjustment factor shall be applied where the current-carrying conductors in these cables that are stacked or bundled longer than 600 mm (24 in.) without maintaining spacing exceeds 20.
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Re: bundlig over 24"

That's why I say yu da man, cause you cold nailed it.

I think that's where the idea to impress the other guys came from.

Edit: There was an inter lingo thing that was buggin me.

[ February 16, 2005, 06:18 PM: Message edited by: physis ]
 
Re: bundlig over 24"

Originally posted by physis:
you cold nailed it.
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Thanks Sam, but as I run a lot of MC I should be aware of the MC requirements. :)

Now ask me a question about classified locations and I have no clue. :(
 
Re: bundlig over 24"

i figured 20 conductors at 50% would be 15 amps. am i correct or do i have everyone confused?
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What table did you use for this calculation. I see Table 310.16 12THHN at 90 C is 30 Amps. 75 at either 20 or 25 Amps but not listed as THHN.
 
Re: bundlig over 24"

As stated by Iwire, look at 310.15(B)(2) Exception No.5

Roger
 
Re: bundlig over 24"

Norb, you're welcome.

Roger
 
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