heat trace feeder and 427.22

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mjmike

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We have a project where there is a 480V 3-phase heat trace control panel that serves multiple individual 20A 277V rated heat trace cables. Inside the heat trace panel, there is a normal thermal mag main disconnect. It serves the individual heat trace cable 20A breakers which are GFEP. Even though each heat trace cable has its own GFEP, reading 427.22, it appears our feeder to the heat trace panel will also need GFEP.

"ground-fault protection of equipment shall be provided for electric trace heating and heating panels"

The ...and heating panels... is what is making me think we need GFP on the feeder as well. Reading the commentary in the handbook seems to indicate something different but that is not "code". Speaking to the heat trace equipment manufacturer, they indicated if we GFEP the feeder breaker, it will trip due to the downstream GFEP branches. We will be posing the question to the AHJ but I wanted to see if anybody else had run into this issue before.
 

david luchini

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We have a project where there is a 480V 3-phase heat trace control panel that serves multiple individual 20A 277V rated heat trace cables. Inside the heat trace panel, there is a normal thermal mag main disconnect. It serves the individual heat trace cable 20A breakers which are GFEP. Even though each heat trace cable has its own GFEP, reading 427.22, it appears our feeder to the heat trace panel will also need GFEP.

"ground-fault protection of equipment shall be provided for electric trace heating and heating panels"

The ...and heating panels... is what is making me think we need GFP on the feeder as well. Reading the commentary in the handbook seems to indicate something different but that is not "code". Speaking to the heat trace equipment manufacturer, they indicated if we GFEP the feeder breaker, it will trip due to the downstream GFEP branches. We will be posing the question to the AHJ but I wanted to see if anybody else had run into this issue before.

A "heating panel" is a piece of heating equipment, not the panelboard that supplies the heating circuits. See 427.23.
 

mjmike

Senior Member
I would tend to agree with that based on 427.23(B) however, I would think there is some interpretation there. Based on the understanding "heating panels" are not the heat trace control panel, and each heat trace has its own branch GFEP, then the main feeder does not appear to need GFEP.
 
Heat Tracing Panels

Heat Tracing Panels

424.90 and .91 identify the basis of "heating panels" as "Electric Radiant Heating Panels and Heating Panels Sets".

The confusion is understandable, since the word "panels", is multiuse, but is mostly referenced to control or distribution situations.
 
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