Control Panel Requirements: UL508A & NFPA 79

[jlt72]

NEC articles 90.7 and 110.3 make it clear that electrical equipment must be "suitable," and the best way to indicate suitability of a control panel is via third-party listing. In the US, that typically means UL508A listing. As I read Article 409, UL508A listing isn't explicitly required. It's just one option.

But what if the control panel will be installed as part of a piece of industrial machinery as defined in Article 670.2? Does this then mean that the control panel construction must follow the requirements in NFPA 79 as well? Or does NFPA 79 just govern the installation of these control panels? It's not clear to me if NFPA 79 is mandatory, and if so, when. Any thoughts?

Thanks!

 

[petersonra]

NEC articles 90.7 and 110.3 make it clear that electrical equipment must be "suitable," and the best way to indicate suitability of a control panel is via third-party listing. In the US, that typically means UL508A listing. As I read Article 409, UL508A listing isn't explicitly required. It's just one option.

But what if the control panel will be installed as part of a piece of industrial machinery as defined in Article 670.2? Does this then mean that the control panel construction must follow the requirements in NFPA 79 as well? Or does NFPA 79 just govern the installation of these control panels? It's not clear to me if NFPA 79 is mandatory, and if so, when. Any thoughts?

Thanks!

NFPA79 is a consensus standard. it means that by and large a significant number of people have agreed it is an appropriate electrical standard for industrial machinery. There is no direct requirement to actually follow it. OSHA does strongly "encourage" employers to do so though by various means.

It is true that the NEC does not require listing for ICP. OSHA more or less does, at least for employers. Some AHJ do as well.

If an ICP is part of a machine it is still an ICP and whatever requirements there are for ICP in that jurisdiction still apply.

By the way, if an ICP for an industrial machine is made to UL508a standards, it will meet NFPA79 requirements for an ICP as well.

 

[jlt72]

Thanks for the quick feedback.

 

[david.mullins]

I have a similar thread if you search for Industrial Control Panel.

I discovered a couple of things:
What standard applies depends 99.9% on the authority having jurisdiction (local or state fire marshals, inspectors, etc.). They can, in theory, require the panel to meet the NEC which then forces you to not take advantage of anything in any other applicable standard like NFPA 79.

If you call the NFPA, they will not answer a question like this, I assume for reasons of liability. They will tell you that there is material in both NFPA 70 and 79 which addresses industrial control panels. However, NFPA 70 really only addresses nameplate requirements for industrial machinery.

NFPA 79 addresses the industrial machinery, "commencing at the point of connection of the supply to the electrical equipment of the machine.” (see the Scope section) They are also considered part of the industrial machinery included in the definition, from NFPA 79 section 3.3.54 by reference to NFPA 70 670.2: "The associated electrical equipment, including the logic controller(s) and associated software or logic together with the machine actuators and sensors, are considered as part of the industrial machine."

UL is a company which, by means of their own set of standards, certifies that equipment is suitable for certain applications. They, like the NEC (which is strictly a standards organization), have no authority to demand anyone apply any standard, whatsoever.

Now, no matter what you interpret that I have just said, or anything else you may have discovered, at the end of the day, some local authority, where the equipment is to be used will have to decide if the equipment is suitable for the application.