Ok guys and gals, here's another question and this time I won't bring up the green screw issue If we are installing or inspecting a heat tape as described in Article 422 Section 422..50. Must it comply with Article 427 Section 427.22? And if so, would you accept or install GFCI protection as an alternate?
I think that 427.22 applies and that a GFCI provides more protection that what is required by the code so it should be permitted. However, if the length is long, the normal leakage current from the heat tape may cause the GFCI to trip. Remember that the nominal trip point of a GFCI is 1/6 of the trip point of the GFP protection required by the code. Don
I think GFCI protection is not permitted because the article specifically calls for GFPE. From a practical perspective, a GFCI protected circuit would have nusiance tripping and would soon be replaced with only standard overload protection. GFPE is available in 30 or 50ma trip level and only in the breaker version. Cost of GFPE about $100 and cost of GFCI a fraction of that.
George, Have you made installations using GFCI and had problems? I don't see a nusiance tripping as a problem in a normal dwelling unit application because the heat trace length is too short. I also don't see that as a violation. The Consumer Product Safety Commission recommends the use of GFCI protection for heat tapes and in a mobile home 550.13(E) requires the heat trace receptacle to have GFCI protection. Don
[This message has been edited by resqcapt19 (edited 05-24-2004).]
Don- I have bee an inspector for 20 years and even when I wore the tools, I don't recall there being a need for GFPE or GFCI for heat tapes. I installed so few of them that I don't remember having a problem at all. Read your CPSC reference- Thank You- My comment would be that the CPSC is not up to speed with the current code on heat tracing. As to the Mobile Home setting, we are not sent to Article 427 for protection but instead ask for GFCI. This type of thing makes me crazy. GFPE is equipment protection and GFCI is people protection. I know you are aware of that and maybe 427 was intended for other than mobile homes. I do think that in other than moblle homes, Article 427.22 applies. Hope we get other comments.
Use a ground-fault circuit-interrupter (GFCI) wherever heat tapes are plugged in.
That is the part of the CPSC statement that I was thinking about. The first GFP requirement was in the '87 code and only applied to heat tape that did not have a metal covering. The proposal called for GFCI, but was revised to GFP at the comment stage. The reason for the change was that on long industrial type installations that the normal leakage current would often exceed the 5mA trip point of a GFCI. In the 96 code the GFP requirement was expanded to cover all heat tape, even that with a metllic covering. This was based fires that were started by heat trace, even with a metallic jacket, when protected by standard breakers. 96 was also the year that 550 required GFCI protection for the mobile home heat trace receptacle. One of the substantiations said that 60% of the heat tape related fires occur in mobile homes. There were comments that recommended GFP in place of GFCI, but they were rejected. This same issue (GFP vs GFCI) was addressed again in the 99 code cycle with CMP 19 requiring the continued use of GFCI protection. The panel statement said in part "the panel's intent is to provide protection for personnel".
Re: Pipe Heating tape#88261 05/25/0405:47 AM05/25/0405:47 AM
One final thought- We are talking about heat tracing on pipes with a cord and cap connection and when we move to snow and Ice melting equipment as in roof tapes, we are back to GFPE if I;m not mistaken.
Re: Pipe Heating tape#88263 05/25/0407:15 AM05/25/0407:15 AM
After doing some research and thanks to Don we have the CPSC suggestion, I find that based on 426.28 the mandatory word "shall" pops up and it looks like we will need GFPE for snow melting equipment. And back to heat tracing, I'll allow GFCI protection for heat tapes as used on mobile homes but that's it. I mean, where's the CPSC when you are in court defending the NEC?