Heat Tracing in Classified Area 1

[stripedbass]

How would this be handled: A weld shop is in an unclassified area and contains a small compressor. The discharge of the compressor has copper tubing that runs through the outside wall, goes underground and exits the ground in a classified area (Class I, DIV II). The tubing is not buried deep enough and some moisture is freezing in the line.

The project managers want to heat trace the tubing with heat tracing that is plugged into a 120V receptacle in the weld shop and follows the tubing out of the shop and into the classified area.

My questions are:

1. Do we plug the heat tracing into a ground fault receptacle?

2. What issues are there running 120V heating element from unclassified to a classified area. (Underground) Suppose that we had to run new tubing above ground and heat trace and insulate it? (The ground is frozen and I'm not sure we can dig up the existing tubing until spring)

The heat tracing is power consumption is 5 watts/ft.

3. Are there any NEC paragraphs that cover this area?

thanks,

SB

 

[resqcapt19]

427.22 requires GFP protection for the heat trace. This is a 20 to 30 mA ground fault trip as opposed to the GFCI 5 mA trip. If the heat trace is short, the GFCI should work fine. Longer runs may have enough leakage to trip the GFCI. 501.10(B) gives the requirements for electric heat in classified areas. Heat trace listed for Class 1 Division 2 is readily available.
Don

 

[peebee]

I suspect you'd need a seal at the boundry. I don't think you'd want to seal the trace itself, though. I'd consider two lengths of trace, one on each side of the boundary. If need be, seal the power supply conductors feeding the trace in the XP area.

30mA GFI is required as mentioned by resqcapt19.

 

[peebee]

One more thought -- maybe a dryer would eliminate the problem moisture in the first place.

 

[kuwait]

I too agree with peebee, a commercial dryer multistage or online FRL (FILTER+REGULATOR+LUBRICANT) unit should serve your purpose, instead of going for an extensive heat tracing and its associated modalities.You may contact FESTO for futher info

 

[Burnerguy]

When using heat trace when is it necessary to use a ground fault.
If I am running 5 5 foot sections is it necessary to put a gfi on each zone?

 

[peebee]

Burnerguy -- see NEC 424.3 & NEC 427.22. The "ground fault protection of equipment" is means 30mA (compared to 5mA for personnel protection).

Also -- this probably should have been posted as a new question -- see faq731-376 .