Wire Protection

[bthielen]

I was wondering if I could get some assistance.

I was inspecting a project I designed this morning on one of our machines (we build packaging machinery) and noticed something that our assembly team did that I'm not sure I liked and I don't believe is code compliant.

Here's what I saw.

The assembly team that fitted the machine conduit decided to enter the enclosure from the rear. This forced them to also cut 1-1/4" knockout openings in the enclosure's panel to bring the wire into the enclosure. This is where I raised a red flag. They did not install any type of bushing, grommet, etc. to protect the wires from the edge of the panel opening.

I have been searching NFPA79 and NEC but have not been able to find anything related to this practice. I have found information pertaining to conduit openings but in this case, it is really not a conduit opening because the conduit is fastened to the enclosure and not the enclsoure's panel.

Anyone know of any code reference(s) that apply?

Thanks,

Bob

 

[petersonra]

Re: Wire Protection

NFPA 79

see 14.5.1.2

 

[bthielen]

Re: Wire Protection

Bob,

Thanks. This seems to suggest that deburring or otherwise eliminating the sharp or rough edges is all that is required. Do you know what determines "where necessary" in the the second sentence other than a judgement call? Today, being the designer, I made the call and requested protection be used on the panel in question because I could envision vibration wearing through the insulation on 480v motor wires and servo drive cables.

Bob

 

[charlie b]

Re: Wire Protection

It sounds like you made a good "business decision," a term that is, of course, different from any code compliance issue. You are spending a little extra of your company's money by taking steps to prevent the customer from experiencing a failure. Call it "cheap insurance," if you will, but I call it a "good call."

 

[hardworkingstiff]

Re: Wire Protection

I 2nd what Charlie said.

 

[pierre]

Re: Wire Protection

300.4 Protection Against Physical Damage. Where subject to physical damage, conductors shall be protected.

This section is very broad in nature and very much a judgement call.