Article 727 and Industrial Machines

[harmon.konrad]

I have been building industrial automation equipment for 6 years now and finally bumped into this gem of an article.

Cable trays and cable tracks carry both ITC cable and TC cable from the cabinet to the motor. Why is this allowed if 727 specifically says you can't install ITC next to any cable of a power circuit?

I this point I have just confused myself. I know we do it. Inspectors buy it off. Everyone in industry does it.

 

[harmon.konrad]

NFPA 79.13.1.3 says you can put conductors of different circuits next to each other as long as they don't impair function and the outside insulation rating is that of the highest voltage conductor.

I think I found it.

 

[don_resqcapt19]

Is this provided by the industrial machine manufacturer? If not, it would be my opinion that the rules in NFPA 70 and not NFPA 79 apply to that wiring. See NFPA 79, 1.4.

 

[harmon.konrad]

I am the industrial machine manufacturer...

 

[don_resqcapt19]

Are you installing the system? Even if you are, the installation may fall under section 1.4 in NFPA 79, and require compliance with the NEC.

 

[tom baker]

Don and I were typing at the same time. If the cable tray is external to the control cabinet, doesn’t the NEC apply?

 

[petersonra]

Don and I were typing at the same time. If the cable tray is external to the control cabinet, doesn’t the NEC apply?

Maybe. If it is a fixed part of the machine probably not. If it was added in the field probably yes.

 

[harmon.konrad]

There is a lot of debate where the lines are drawn. We make factories and we make corded equipment. Depending on the customer and the inspector they decide ultimately what they want us to follow. Hazloc stuff gets a bit more restrictive falling on the NFPA 70 side. NFPA 79 specifically ignores Hazloc and says refer to 70. What happens in my experience is you end up having to follow the strictest of both.

We always do the installation. Everything I install more or less falls under the exception under 1.4 if I interconnect anything. I think the exception also answers Tom's question. Our "field wiring" is integral to the machine and often goes through movement axis in energy chains.