MTW run in conduit or only THHN

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jmarsan

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Can MTW be ran in conduit for lighting fixtures? The run is 36" long going to a 4 x 4 box then to Flex conduit into the lights. This is an industrial work station located in Zeeland, Michigan. The lights are 2' x 4' four bulb fixtures. I would like to know if the NEC or the NFPA 79 states that I can not do this.

Thanks
Jmarsan
 
jmarsan said:
Can MTW be ran in conduit for lighting fixtures? The run is 36" long going to a 4 x 4 box then to Flex conduit into the lights. This is an industrial work station located in Zeeland, Michigan. The lights are 2' x 4' four bulb fixtures. I would like to know if the NEC or the NFPA 79 states that I can not do this.

Thanks
Jmarsan
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NFPA79 would not apply unless the lighting fixtures are part of a machine. If that is the case, the NEC would not apply as it is not premises wiring.

I don't believe either one prohibits running MTW in conduit. Its a whole lot easier to run THHN though.
 
Read section 310.13 and table 310.13.

Most recognized conductor types have the application provision of 'dry and damp locations' or 'dry locations only' or 'dry and wet locations'. MTW says 'Machine tool wiring in wet locations...Machine tool wiring in dry locations...', strongly implying that this wire type can only be used in machine tools.

With that said, I am looking at the 2002 code book (which I happen to have at hand) and the section may have been changed.

Also note that many conductors have multiple ratings. The stranded THHN that I have on the shelf is also rated MTW and THWN-2. Perhaps the MTW that you want to use is also rated THHN.

-Jon
 
True MTW is THHN without the plastic coating. I do not see it listed in 310. It's very similar to THW. I think it is rated at 90 degree, so it should be fine for this application.
 
Unless you're buying it special, it's not too often lately that your MTW won't also be marked with additional NEC compliant conductor types. Usually TFF or TFFN, if you look carefully.
 
Can MTW be ran in conduit

Can MTW be ran in conduit

Thanks for your in put...I did this due to someone saying "What if I were color blind" and I figured I can help with that. As it turns out there are team members in my dept. that are color blind!
 
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