Control Panels Ampacity of wire

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sjerome

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I was trying to properly size control wire ing and power wiring inside a nema 12 control panel. Can the control wiring and power wiring be sized from 310.17 open air or 310.16 and if it is ran in wiring duct with the slots I would think a raceway inside the control Panel. I understand about the temerature ratings of the terminals and ambient temp also about derating for three or more in a raceway. But its not spelled out very clear about inside control panels.
 
Sjerome,
Grounding conductors are spelled out in UL508A table 15.1
Ampacities of Power insulated conductors are in UL508A Table 28.1
Ampacities of Control Circuit wires are in UL508A Table 38.1
Color coding of wires are in UL508A section 66.5.3 and 66.9.1
I hope this helps you.
 
sjerome said:
I was trying to properly size control wire ing and power wiring inside a nema 12 control panel. Can the control wiring and power wiring be sized from 310.17 open air or 310.16 and if it is ran in wiring duct with the slots I would think a raceway inside the control Panel. I understand about the temerature ratings of the terminals and ambient temp also about derating for three or more in a raceway. But its not spelled out very clear about inside control panels.
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Keep in mind that the NEC basically does not apply inside the control panel. It is about premises wiring.
 
Keep in mind that in NEC 2005 Article 409 for Industrial Control Panels, it addresses UL508A as a guide, not NFPA79. You would be better served IMO, in purchasing a copy of UL508A, all 242 pages.
Just my $.02
 
UL 508 can be purchased in hardcopy or electronic form at the following website: http://www.comm-2000.com/. Also be aware that NEC section 490 has specific requirements for industrial control panels that are often overlooked since this was a new section in the 2005 edition.
 
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