U.L. vs. NEC

[anomaly]

Our products (electric infrared heating systems) are listed under U.L. 2021 which states (in part), "Heating equipment employing infrared heating means shall have overcurrent protection not exceeding 50 amperes."

The 2005 NEC article 424 for "Fixed Electric Space-Heating Equipment" states in 424.3(A) that "In nondwelling occupancies, fixed infrared heating equipment shall be permitted to be supplied from branch circuits rated not over 50 amperes."

I am asking........isn't this a contradiction? I am trying to assure that our documentation is correct. Thanks for the assistance with this!!!

 

[iwire]

Whats the contradiction?

I see both allow overcurrent protection up to 50 amps with the NEC specifying non-dwelling units.

 

[anomaly]

Doesn't the NEC statement allow branch circuits up to 50 amps and therefore imply that overcurrent protection would be in excess of 50 amps thereby contradicting the U.L. requirement?

 

[muskiedog]

I don't see that. Are you reading into something that isn't there?

 

[cowboyjwc]

It says "...rated not over 50 amperes."

Looks like they say the same thing to me.

 

[anomaly]

You're probably right........overanalysis is one of my strengths. I think I know what to do. Thank you.