UL508A vs NEC 409

[Rolson]

We are an OEM that is looking into building panels for our equipment. I have read several articles about this topic but very few have brought up NEC 409. If we were to build panels in accordance with NEC 409 would there be any reason that the AHJ would kick it back for not being NRTL listed? In my past experience is if we have all the labeling requirements for the NEC 409 by the OEM, our local AHJ has accepted it.

 

[petersonra]

We are an OEM that is looking into building panels for our equipment. I have read several articles about this topic but very few have brought up NEC 409. If we were to build panels in accordance with NEC 409 would there be any reason that the AHJ would kick it back for not being NRTL listed? In my past experience is if we have all the labeling requirements for the NEC 409 by the OEM, our local AHJ has accepted it.

The NEC does not require Industrial Control Panels be listed so i see no reason that in general the local inspector would have an issue with it, although my understanding is at least a few jurisdictions do require listing.

OSHA is another thing though. They have posted a letter stating control panels do need to be listed although it does not appear to be something they enforce very rigidly.

If you are building a substantial number of panels the extra cost is not a big deal to be able to list them. If you are a small place that only builds a few dozen a month the cost might put you at a competitive disadvantage. If that is the case you might want to consider having a UL508a panel shop build the panels for you. It is likely that the cost will be about the same and you won't have to pay extra to get them listed for the customers that do need listing.

 

[tom baker]

WA requires control panels to be listed by an acceptable testing agency (ETL, CSA-U, UL), panel shops follow UL 508A. The requirement in WA has been a statue (law) since 1935.
I have installed hundreds of control panels, when the AHJ opens the door and he sees the UL label, all is good. No UL, the job stops and someone will pay UL about $2K for a field evaluation.