Enclosure Installation - Metal Chips

[billn2000]

A NEMA Type 2, Service Entrance Rated, motor controller is being installed, 50HP, 3/60/480. Installing personnel are required to punch conduit holes in the top and bottom enclosure surfaces for line and load connections.
What are the installer's responsibilities, if any, for preventing metal chips and shavings from contaminating the circuit breaker and the solid state low voltage control equipment in the enclosure? Is a hole saw accepted practice vs. a pilot hole and hole punch? Where is "contamination exclusion" addressed in NEC?

 

[hockeyoligist2]

I don't think the NEC addresses this. You will still get shavings from pilot holes. The standard practice that I have always used is duct tape and plastic over all componants or remove them, if possible, before drilling. I would say that whoever is drilling is responsible for keeping everything out. The NEC does address "workmanship" and a good electrician would keep them out.

Just My Opinion!

 

[petersonra]

and vacuum afterwards.

 

[infinity]

We try to always punch the ko's. However this still requires a 7/8" hole. For this I always use a circular magnet taken from an old car speaker. Stick it to the can and drill inside of it. Catches about 99% of the filings. A piece of cardboard on the inside stops the rest.

 

[iwire]

I always figure I break it I buy it. In other words if I am drilling it's my responsibility to protect the equipment somehow.

I always use a circular magnet taken from an old car speaker. Stick it to the can and drill inside of it. Catches about 99% of the filings.

Nice idea, I will have to try that.

 

[cowboyjwc]

I made that mistake one time. Got in a hurry and wasn't really paying any attention. Putting it in the second time hurt my pride and my wallet.