Heat Trace / GFIC

[sockie1924]

When designing for heat trace in the code it says to allow for 125% of the load and to be GFCI. In one company's catalog is says to use GFCI with a 30 miliamp trip setting when specifing the breakers where can I find what the trip setting is for the different breakers like 20A-1P or 30A-1P. Where can I find the miliamp trip raiting??

 

[Guest]

Re: Heat Trace / GFIC

Look for Class B. Class B is 30mA [Edit: This is wrong, see my next post below].

For example, AFCI's have Class B GFCI protection. [Edit: This is wrong per Article 100 per Don, but correct per Handbook as mentioned in my next post].

[ October 20, 2003, 10:16 PM: Message edited by: awwt ]

 

[don_resqcapt19]

Re: Heat Trace / GFIC

The term "GFCI" is reserved for 5 mA ground fault protection for people. The correct term for the protection required by Article 527 is "GFP". Most breaker manufcaturers have both GFCI and GFP breakers. They look identical except for a warning on the GFP that says "not for shock hazard protection" or something to that effect. Here is a link to Square D's QO-EPD breaker.
Don

 

[Guest]

Re: Heat Trace / GFIC

I'm glad you made me look that up because my answer is wrong. A Class B GFCI is 20mA (not 30mA as I stated above) according to the 2002 NEC Handbook (Yes, it says GFCI and this is contrary to Article 100 where it specifies that GFCI are Class A):

NEC 680.5 Ground-Fault Circuit Interrupters.
Ground-fault circuit interrupters (GFCIs) shall be self-contained units, circuit-breaker or receptacle types, or other listed types.
See the definition of ground-fault circuit interrupter in Article 100.

[HANDBOOK] A ground-fault circuit interrupter is intended to be used only in a circuit that has a solidly grounded conductor; however, an equipment grounding conductor is not necessary in order for the GFCI to function. A Class A GFCI trips where the current to ground has a value in the range of 4 through 6 mA; it is suitable for use in swimming pool circuits. It should be noted, however, that circuits supplying pool equipment that were installed before local adoption of the 1965 edition of the Code may have sufficient leakage current to cause a Class A GFCI to trip. A Class B GFCI trips if the current to ground exceeds 20 mA; it is suitable for use only with underwater swimming pool lighting fixtures installed before the local adoption of the 1965 Code.

For more information see NEC 210.8 Ground-Fault Circuit-Interrupter Protection for Personnel. and Handbook Exhibits 210.7 through 210.15. Also, see 215.9 & 215.10. Furthermore UL UL 943, Standard for Ground-Fault Circuit Interrupters.