MC Cable

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lektrik33

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310-15 B (2) a Exception #5 states that adjustment factors shall not apply to MC Cable without an overall jacket under the following conditions. My question is what is meant by "overall jacket"???
 
Re: MC Cable

310.15(B)(2) Exception No.5 refers to the use of MC wires bundled together in a panel board with obviously the outer "metal clad" sheath removed. In other words, no derating is required for these wires located & bundled within the panel board. ;)
 
Re: MC Cable

Originally posted by sbe:
310.15(B)(2) Exception No.5 refers to the use of MC wires bundled together in a panel
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No it does not have to do with MC wires bundled together in a panel


Originally posted by sbe:
In other words, no derating is required for these wires located & bundled within the panel board. ;)
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sbe follow Dons link, he has the correct answer to this question.

The code in question has to do with MC with an overall PVC jacket.

[ April 18, 2004, 11:03 AM: Message edited by: iwire ]
 
Re: MC Cable

Bob, I followed Don's link to the specifications page for the PVC jacketed MC cable and I agree with you that NEC article 310.15 (B)(2) Exception No.5 applies, please also note that IMHO, that exception also applies to the panel board scenario. :)
 
Re: MC Cable

Welcome Howard. :)

I do not have anything that I can use to demonstrate what that exception is about, but I ask you what makes you think it applies to panels? :confused:

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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Take a look at part (a) it says "cable" once stripped it is no longer a cable it is conductors and part (c) I have not seen bridle rings used in a panel.

IMO this exception is clearly for MC cable runs outside the panel.

Bob
 
Re: MC Cable

Hi Bob,
I will research this topic and get back to you. Thanks for your input.

Howard
 
Re: MC Cable

Nice link Howard. :)

The derating for conductors bundled in a panel would only apply if the conductors are bundled longer than 24" wouldn't you think?

310.15(B)(2)Adjustment Factors.
(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).
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Bob
 
Re: MC Cable

What do you folks who use PVC coated MC Cable pay for the cable and the connectors?

I got a price from my foreman of $650 per 1000' and like $3.50 a connector.

What do you pay and who is your supplier?
 
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