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Author Topic: #2 SC 200a feeder cable?  (Read 4345 times)

Guy Holt

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Re: #2 SC 200a feeder cable?
« Reply #10 on: April 18, 2015, 09:05:44 am »

Is this true? I had no idea.

Yes, but Article 530.18 "Overcurrent Protection (A) Stage Cables" of the NEC pertaining to “Motion Picture Studios and Similar Application” allow overcurrent protection to be up to 400 percent of the rated ampacity of the cable. The exact wording is a follows: “Stage cables for stage set lighting shall be protected by means of overcurrent devices set at not more than 400 percent of the ampacity given in the applicable tables of Articles 310 and 400.”  And, according to NEC Table 400.5(B) the rated ampacity of #2  90 degree SC cable is 190 Amp, which means that according to the NEC you could use up to a 760A breaker.  There is not a municipal inspector in the country that would countenance that. My point being that the NEC is a national code that a municipality can elect to adopt or not. It ultimately comes down to the Authority Having Jurisdiction and what they want you to do. The local electrical inspector has the final say, so it is worth finding out ahead of time what they want and don't bother trying to cite code to them.

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com
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boburtz

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Re: #2 SC 200a feeder cable?
« Reply #11 on: April 18, 2015, 12:56:46 pm »

It's only money, right?
Unless you count the fun factor. 2/0 is WAY less fun to deal with than #2.
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Tim McCulloch

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Re: #2 SC 200a feeder cable?
« Reply #12 on: April 18, 2015, 01:16:49 pm »

Yes, but Article 530.18 "Overcurrent Protection (A) Stage Cables" of the NEC pertaining to “Motion Picture Studios and Similar Application” allow overcurrent protection to be up to 400 percent of the rated ampacity of the cable. The exact wording is a follows: “Stage cables for stage set lighting shall be protected by means of overcurrent devices set at not more than 400 percent of the ampacity given in the applicable tables of Articles 310 and 400.”  And, according to NEC Table 400.5(B) the rated ampacity of #2  90 degree SC cable is 190 Amp, which means that according to the NEC you could use up to a 760A breaker.  There is not a municipal inspector in the country that would countenance that. My point being that the NEC is a national code that a municipality can elect to adopt or not. It ultimately comes down to the Authority Having Jurisdiction and what they want you to do. The local electrical inspector has the final say, so it is worth finding out ahead of time what they want and don't bother trying to cite code to them.

Guy Holt, Gaffer
ScreenLight & Grip
www.screenlightandgrip.com

Guy, what we're doing is almost 100% covered in 520 and 525.  The MP codes are much more lenient.
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Stephen Swaffer

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Re: #2 SC 200a feeder cable?
« Reply #13 on: April 20, 2015, 11:13:26 pm »

Code allows the next larger standard breaker size (defined in code) on circuits under 800 amps.

Since you asked,

This is true, but not for branch circuits feeding cord and plug connected loads.  So this would be true for a distro, since it would have OPCD for the branch circuits.  (Branch circuits, by definition, being the wiring after the last OCPD).  NEC 240.4 (B).  Standard fuse/breaker sizes are found in 240.6 (A).
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Steve Swaffer
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