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#191854 01/16/10 01:13 PM
Joined: Oct 2004
Posts: 55
A friend of mine is involved in installing (physically) various types of industrial machinery at a company. He recently installed an industrial machine and the electrician refused to do the electrical connection as the machinery itself isn't listed, although it does have a label with all the pertinent information.

My reading of the NEC indicates that some specific devices have a listing requirement. For example, if my friend had installed an electrical heater under Article 424, 424.6 requires that the heater is required to be listed. In this case, if the heater wasn't listed, the electrician would be correct, he couldn't do the electrical connection. However, Article 670, Industrial Machinery, does not indicate that listing is necessary for the machine itself. The FPN in 670.1 indicates that the machinery has to have sufficient information on the label to allow the electrician to wire the machinery with the proper sized conductors, overcurrent protection, etc. But the machine itself does not need to be listed. 670.1 gives me the impression that the NEC only deals with the installation up to the disconnect for the machine, and not beyond that point.

Obviously, everything in the electrical system proper has to be listed. Looking through the NEC at the other articles shows that some specific devices have to be listed, others have to be labeled, and some show no specific requirement other than being approved by the AHJ. Is this correct?


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Joined: Apr 2002
Posts: 7,333
Likes: 7

From the '08 NEC Handbook CD:

"Approved. Acceptable to the authority having jurisdiction."

Commentary from the Handbook......
See the definition of authority having jurisdiction and 110.2 for a better understanding of the approval process. Understanding NEC terms such as listed, labeled, and identified (as applied to equipment) will also assist the user in understanding the approval process.
Listed equipment will more readily be approved by an authority having jurisdiction where the authority accepts the laboratory's listing mark. Other options may be available for the jurisdiction to approve equipment, including evaluation by the inspection authority or field evaluation by a qualified laboratory or individual. Where an evaluation is conducted on site, industry standards such as NFPA 79, Electrical Standard for Industrial Machinery (if applicable), should be used.

As there are no specifics within Art. 670, the subject becomes a call for.....the electrician responsible to tie-in, and the AHJ...if it's a job to be inspected.

Joined: Jan 2005
Posts: 5,370
Likes: 1
Cat Servant
There's a tremendous amount of equipment out there that is perfectly safe, 'state of the art,' and not listed. Not by UL, or anyone else.

UL has a strong presence in some industries, and a very weak presence in others. Even control panels are not usually listed; and even a 'listed' panel can be designed in a manner that operates equipment in an unsafe manner.

If the electrician doesn't feel comfortable, that's his call to make. If the customer encounters this with a few electricians, there might be something else going on.

Joined: Jul 2007
Posts: 1,335
Most industrail equipment is custom built thus the maufacturer's libility is the equipment's llisting. The electrical equipment will likely be listed thus meeting the requirement. Kind of of like building a modular house. The house as a whole Is not listed, just the electrical components. We just hook up the power and go away.

"Live Awesome!" - Kevin Carosa
Joined: Jan 2004
Posts: 1,507
Look at the scope of Article 670 and then 670.3, you'll notice that there is a requirement for a name plate the word "shall" is used and as long as it has a name plate, a disconnect, properly sized wires and overcurrent protection (based on the name plate) no problem for me as an inspector or an electrician as long as he connects the machine based on the name plate.

George Little
Joined: Jul 2002
Posts: 8,432
Likes: 3
My first question would be.
What sort of machine is it?
As in, what does it do and what is it made up of?

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