Heating Panel & NEC 427.22

[kerickson]

The interpretation of the term "heating panel" is currently under question in a situation I am involved with. According to NEC 427.22, "Ground-fault protection of equipment shall be provided for electric heat tracing and heating panels." The exception listed after that sentence does not apply in this situation.

The situation is that there is an electrical distribution panel at a biodiesel fuel storage site which provides power to tank heaters for the biodiesel tanks. There is no heat tracing on the pipelines anywhere in the facility, just heaters that go into a well into the tank to keep the biodiesel fuel at the proper temperature. The owner of the facility is questioning whether or not ground fault protection is needed at this tank heater panel.

So, would the "heating panels" referred to in this code section apply here? :-?The "electric heat tracing" does not apply to this situation, so if "heating panel" does not either, they would not need the ground fault protection. If you need more information on the heating panels in order to answer the question, please let me know what is needed.

Thank you for your prompt help!

 

[charlie b]

I think not. The context of the word "panel" does not appear to be that of a branch circuit panel (i.e., one that serves heating loads), but rather that of a flat surface that is (somehow) caused to become hot, and that therefore transfers heat to some other object.

 

[kerickson]

Thanks Charlie. Can I ask how you came to that conclusion? The client we're working with will likely want more "proof" than simply that it is an individual's point of view.

 

[charlie b]

I can't begin to guess what they might accept as constituting "proof." But let me invite your attention to 427.23(B). From that description of what a heating panel must have, it is clear that the code is not talking about a branch circuit panel that serves heating loads.

 

[markstg]

I'm with Charlie on this. We have many electrical immersion heaters in tanks and vessels and all are protected with thermal magnetic breakers.

 

[hurk27]

To me the requirement of GF protection of the heating element load is required anytime you have a resistive heating element, as this could constitute a heating panel, just because it is mounted in a well doesn't change the fact it is a "panel made up of resistive heating elements that produce heat by passing current through an element, 427 is also about vessels and this does describe a tank of bio-fuel as such, I would think a GF (30ma) breaker in the feeding circuit would meet this requirement. if a element was to fail and make contact with the wall of the well, (not knowing all the specifics) it could possibly burn through the well and cause an ignition of the fuel?

other requirements might come into play if the fuel has a flash point above 100?F like Articles 500 through 516.

The definition of a heating panel is vague, but I would think the intent is to prevent the above from happening?

of course if you meet the 3 requirements of 427.22 it wouldn't be required?

 

[markstg]

Hurk,

How about electric resistance heaters mounted in panels or in motors. Do these need GFI protection in your view?

 

[petersonra]

(B) Heating Panels. Heating panels shall have a grounded
conductive covering over the heating element and its electrical
insulation on the side opposite the side attached to the
surface to be heated.

This certainly seems to describe a situation where a heater is in direct contact with a hard surfaced device. Think something like a band heater.

An immersion type heater would not be in contact with a surface to be heated, and it has no "side opposite the side attached to the
surface to be heated".