Thread: Snow Melting Equip on AFCI Breakers

Hello, I have nuisance tripping issues on a snow melting system in a commerical building. The voltage is 120/208. This snow melting system has 4 separate heater circuits, each 120V, each on its own AFCI Breaker (Current rating is unknown at this time). The 5th AFCI Breaker which has no trouble at all is for the control equipment (which is just a temp monitor and Normally Closed Contactor). Here is the panel schedule for the breakers in question:
1 (20 A SP Standard breaker) - Rooftop outlets
3 (20 A SP Standard breaker) - Rooftop outlets
5 (20 A SP Standard breaker) - Rooftop J-boxes & Neon Lighting
7 (20 A SP Standard breaker) - Rooftop J-boxes & Neon Lighting
9 (? A SP AFCI Breaker) - Heat tape
11 (? A SP AFCI Breaker) - Heat tape
13 (? A SP AFCI Breaker) - Heat tape
15 (? A SP AFCI Breaker) - Heat tape
17 (? A SP AFCI Breaker) - Controller
9 will hold all day and all night, no problems with this circuit. 11 will trip as soon as you energize it, same for 13. 15 will hold for about 30 seconds, then trip. 17 is the controller and no problems with this circuit. Circuits 9-15 go out to a NC Contactor then up to the roof to be disticuted. The contactor coil is controlled by the controller and is energized when you put the system on delay or the temp outisde is too warm, opening the contacts and shutting off the heat tape runs.
The reason i included information about circuits 1-7 is because if I shut off 1-7, then 11-13 will hold. 15 will still trip after 30 seconds or so. When i energize 1-7, 11 and 13 will trip.
I am thinking that these rooftop devices are all sharig neutrals with my heat tape? I'm not sure about this, but was looking for some ideas out there? Please let me know what you think or if you need more information.

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John,
Since this is a home inspectors forum, I think you would have better luck at a electricians forum, or just call an electrician to check it out for you.

New Member = John Schneider
Posts = 1
Location = Montana

Originally Posted by John Schneider

Hello, I have nuisance tripping issues on a snow melting system in a commerical building. The voltage is 120/208. This snow melting system has 4 separate heater circuits, each 120V, each on its own AFCI Breaker (Current rating is unknown at this time). The 5th AFCI Breaker which has no trouble at all is for the control equipment (which is just a temp monitor and Normally Closed Contactor). Here is the panel schedule for the breakers in question:
1 (20 A SP Standard breaker) - Rooftop outlets
3 (20 A SP Standard breaker) - Rooftop outlets
5 (20 A SP Standard breaker) - Rooftop J-boxes & Neon Lighting
7 (20 A SP Standard breaker) - Rooftop J-boxes & Neon Lighting
9 (? A SP AFCI Breaker) - Heat tape
11 (? A SP AFCI Breaker) - Heat tape
13 (? A SP AFCI Breaker) - Heat tape
15 (? A SP AFCI Breaker) - Heat tape
17 (? A SP AFCI Breaker) - Controller
9 will hold all day and all night, no problems with this circuit. 11 will trip as soon as you energize it, same for 13. 15 will hold for about 30 seconds, then trip. 17 is the controller and no problems with this circuit. Circuits 9-15 go out to a NC Contactor then up to the roof to be disticuted. The contactor coil is controlled by the controller and is energized when you put the system on delay or the temp outisde is too warm, opening the contacts and shutting off the heat tape runs.
The reason i included information about circuits 1-7 is because if I shut off 1-7, then 11-13 will hold. 15 will still trip after 30 seconds or so. When i energize 1-7, 11 and 13 will trip.
I am thinking that these rooftop devices are all sharig neutrals with my heat tape? I'm not sure about this, but was looking for some ideas out there? Please let me know what you think or if you need more information.

I'll not only second J.F.'s comments, but go further.

Not only is insufficient information presented, its lack of information and the summary title and opening assumption are indicitive of someone who knows nothing about what they are doing - and I do not mean this to be insulting, but a clear indication of the potential (pun intended) DANGER which may be present

DANGER!!, yes danger; as in personal injury, death, fire, shock, electrocution hazard.

There are those who "think" or rather "thought" they knew far more about the subject of neon outline and signage lighting, cold cathode or tube,than you have displayed, who unfortunately in recent years, are no more (due to electrocution, i.e. death).

Making matters far more complicated, and concerning, then the apparent DANGER situation with the Article 600 situation, we have complications of an apparently malfunctioning, damaged, and/or improperly installed, heat cable system.

The entirety at this location, esp. all referenced above, should be shut down immediately, and locked out.

A qualified contractor, not just any-ol' electrician, experienced in chapter 6, article 600, up-to-date on CMP 18 and the TCC reports, and further experienced and qualifed with exterior neon signs and outline lighting, and further experienced in tracing and inspecting same, should be contacted immediately to inspect, review, test, trace, and remediate the entirety of what you have described.

I cannot say this strongly enough. DANGER, DANGER, DANGER. Stop fiddling around with what you are unqualifed to do. SHUT THIS DOWN, LOCK IT OUT, and get someone QUALIFIED there POST HASTE (PDQ -Pretty Darn Quick), do not pass go, do not hesitate, 'Get-'er'-Done)!!

You are entirely wrong to presume a nusiance trip situation, or for that matter a singular problem on a singular circuit. QUITE THE OPPOSITE.

The systems and/or components present require immediate inspection, testing, and evaluation by someone QUALIFIED to do so.

If this is an occupied structure or you are inviting prospective occupants, or other parties to visit the property, to work, to review, YOU ARE ON NOTICE that there is a HIGH PROBABILITY that there is likely a clear and present DANGER and HAZARD to Life and Property to those present, and not just "on the rooftop", or for that matter not just in the building.

What is the ACTUAL voltage present? Not 120/208, but the voltage you actually read with a voltmeter. With some breakers turned off then the others holding, it could be the voltage is too low. Also have you checked the resistance of the heater circuits? check the resistance of the tapes, and with the actual read voltage, do the math. There are circumstances where the receptacles for deicing equiptment does not need to be on a GFCI, but I know of no requirement that will require them to be on a AFCI. especially in a commercial building. If this makes no sense, then it may be time to call an electrician as others have suggested.

Originally Posted by Tony Cole

What is the ACTUAL voltage present? Not 120/208, but the voltage you actually read with a voltmeter. With some breakers turned off then the others holding, it could be the voltage is too low. Also have you checked the resistance of the heater circuits? check the resistance of the tapes, and with the actual read voltage, do the math. There are circumstances where the receptacles for deicing equiptment does not need to be on a GFCI, but I know of no requirement that will require them to be on a AFCI. especially in a commercial building. If this makes no sense, then it may be time to call an electrician as others have suggested.

Apparently you got lost in the reading. #15 trips no matter what, even if everything else is off - within 30 seconds . Try again, this has nothing to do with under voltage present it is a pure resistive load.

You seem to have missed the distinction between GFPE and GFCI, since you for whatever reason chose to discuss GFCI. GFPE is ground fault protection equipment.

You apparently also missed the Neon lighting present, the symptoms described, the conditions, or the other equipment present and described.

However, the OP is long since gone and doubt will ever return, as after I posted my response and saw on-line and that was editing his OP, profile, etc. to remove the "information" I had already quoted it so it would remain for posterity.

Under voltage for 120V resistance cable heating and/or relay controller wouldn't have anything to do with an AFCI breaker tripping.

ok thanks

Originally Posted by John Schneider

ok thanks

John,

When you post a question---please don't edit it. Not everyone here looks at something at the same time. Right now I haven't the fog of figuring out what you are asking. If you are not satisfied with what you have written after it appears---post a new note with the correction(s). It would help the folks out here greatly if you did it this way. Thanks!

Rich

OK guys, I had a qualififed electrician fix the problems. I wanted to let you know what he found. Also, I have to correct information I've told you from the start.

Hello, I have tripping issues on a snow melting system in a commerical building. The voltage is 120/208. This snow melting system has 4 separate heater circuits, each 120V, each on its own GFCI Breaker (20 A). The 5th AFCI Breaker which has no trouble at all is for the control equipment (which is just a temp monitor and Normally Open Contactor). Here is the panel schedule for the breakers in question:
1 (20 A SP Standard breaker) - Rooftop outlets
3 (20 A SP Standard breaker) - Rooftop outlets
5 (20 A SP Standard breaker) - Rooftop J-boxes & LED Lighting
7 (20 A SP Standard breaker) - Rooftop J-boxes
9 (20 A SP AFCI Breaker) - Heat tape
11 (20 A SP AFCI Breaker) - Heat tape
13 (20 A SP AFCI Breaker) - Heat tape
15 (20 A SP AFCI Breaker) - Heat tape
17 (20 A SP AFCI Breaker) - Controller

These were the symptoms:
9 will hold all day and all night, no problems with this circuit. 11 will trip as soon as you energize it, same for 13. 15 will hold for about 30 seconds, then trip. 17 is the controller and no problems with this circuit. Circuits 9-15 go out to a NC Contactor then up to the roof to be disticuted. The contactor coil is controlled by the temp monitor and is energized when the conditions are right for the sensors, closing the contacts and energizing the heat tape runs.
The reason i included information about circuits 1-7 is because if I shut off 1-7, then 11-13 will hold. 15 will still trip after 30 seconds or so. When i energize 1-7, 11 and 13 will trip.

This was my original thought:
I am thinking that these rooftop devices are all sharig neutrals with my heat tape? I'm not sure about this, but was looking for some ideas out there? Please let me know what you think or if you need more information.

This is what my electrician's meter readings were:
Line: A - 121 V AB - 207 V
B - 120 V BC - 208 V
C - 119 V AC - 208 V

CKT 1 - 0 A
3 - 0 A
5 - 1 A
7 - 0 A
9 - 57 A
11 - 59 A
13 - 39 A
15 - 12 A

Needless to say, he was quite concerned with these numbers

This is what was found to be the problem:
-There was absolutely no grounding installed in the rooftop j-boxes. The original contractor did not ground anything up there!
-The heat tape neutrals were being shared with other circuits (1-7)
-Not only were the neutrals being shared, the neutrals from the heat tape circuit were landed on the neutral bus and the neutrals for other circuits were landed on the GFCI breaker
-The heat tape cable terminations were not made up correctly. The contractor did not follow the manufacturers installation instructions for terminating the cables.

What he did to fix the problem:
- Pulled in new neutrals to where needed
- Pulled in ground wire to all jboxes and loads
- Sorted out the mixed up neutrals in the panel and landed them correctly
- Remade the heat cable terminations and megged them
- Tested the system

I'm glad its over with! Thank you guys for your help especially Mr. Watson. I truly respect you for setting me on safety and getting it looked at by a professional. I appreciate your concern in the matter of safety. Thanks again everyone.

Originally Posted by John Schneider

OK guys, I had a qualififed electrician fix the problems. I wanted to let you know what he found. Also, I have to correct information I've told you from the start.

Hello, I have tripping issues on a snow melting system in a commerical building. The voltage is 120/208. This snow melting system has 4 separate heater circuits, each 120V, each on its own GFCI Breaker (20 A). The 5th AFCI Breaker which has no trouble at all is for the control equipment (which is just a temp monitor and Normally Open Contactor). Here is the panel schedule for the breakers in question:
1 (20 A SP Standard breaker) - Rooftop outlets
3 (20 A SP Standard breaker) - Rooftop outlets
5 (20 A SP Standard breaker) - Rooftop J-boxes & LED Lighting
7 (20 A SP Standard breaker) - Rooftop J-boxes
9 (20 A SP AFCI Breaker) - Heat tape
11 (20 A SP AFCI Breaker) - Heat tape
13 (20 A SP AFCI Breaker) - Heat tape
15 (20 A SP AFCI Breaker) - Heat tape
17 (20 A SP AFCI Breaker) - Controller

These were the symptoms:
9 will hold all day and all night, no problems with this circuit. 11 will trip as soon as you energize it, same for 13. 15 will hold for about 30 seconds, then trip. 17 is the controller and no problems with this circuit. Circuits 9-15 go out to a NC Contactor then up to the roof to be disticuted. The contactor coil is controlled by the temp monitor and is energized when the conditions are right for the sensors, closing the contacts and energizing the heat tape runs.
The reason i included information about circuits 1-7 is because if I shut off 1-7, then 11-13 will hold. 15 will still trip after 30 seconds or so. When i energize 1-7, 11 and 13 will trip.

This was my original thought:
I am thinking that these rooftop devices are all sharig neutrals with my heat tape? I'm not sure about this, but was looking for some ideas out there? Please let me know what you think or if you need more information.

This is what my electrician's meter readings were:
Line: A - 121 V AB - 207 V
B - 120 V BC - 208 V
C - 119 V AC - 208 V

CKT 1 - 0 A
3 - 0 A
5 - 1 A
7 - 0 A
9 - 57 A
11 - 59 A
13 - 39 A
15 - 12 A

Needless to say, he was quite concerned with these numbers

This is what was found to be the problem:
-There was absolutely no grounding installed in the rooftop j-boxes. The original contractor did not ground anything up there!
-The heat tape neutrals were being shared with other circuits (1-7)
-Not only were the neutrals being shared, the neutrals from the heat tape circuit were landed on the neutral bus and the neutrals for other circuits were landed on the GFCI breaker
-The heat tape cable terminations were not made up correctly. The contractor did not follow the manufacturers installation instructions for terminating the cables.

What he did to fix the problem:
- Pulled in new neutrals to where needed
- Pulled in ground wire to all jboxes and loads
- Sorted out the mixed up neutrals in the panel and landed them correctly
- Remade the heat cable terminations and megged them
- Tested the system

I'm glad its over with! Thank you guys for your help especially Mr. Watson. I truly respect you for setting me on safety and getting it looked at by a professional. I appreciate your concern in the matter of safety. Thanks again everyone.

Although I appreciate the gratitude, your update and latest "corrections" still make no sense.

You introduce the supposed presence of GFCI breakers, yet still identify the breakers as AFCI and Standard type SP breakers.

You reference rooftop outlets which are not gfci, nor have something functioning as a ECG.

You now identify rooftop lighting as LED, which would require a step down transformer, a grounded circuit, GFCI protection, etc (LV).

Pardon me, but I suspect from your description that you either do not have a clear enough understanding of the equipment present, or what was or was not done in the first place, or its corrections; and am still dubious as to the safety to persons and property as you have inadequately described a condition, which as per your description even of the supposed corrections, would remain inadequate and unsafe. Just because something "appears" to be "working" doesn't mean it is "working" electricity correctly or safely.

Equipment with an allowable ampacity limited to 25 A having exposed to and working resistive loads at 200% and 300% of that maximum allowable ampacity should not be re-used. The "idea" that old heat cables (very short useful life even in the best of circumstances concerning use/installation exposed) having been inappropriately subjected to such large overcurrent could be allowed to remain in place is frankly extremely concerning.

Your descriptions of the wiring methods used to "correct" the problem are additionally ambiguous and leave one wondering if Chapters 1-4 and the applicable sections of Chapter 6 were even consulted.

How anyone could confuse Neon with LED confounds me. Yet a Sign is a sign and outline lighting is still outline lighting. That you continue to confuse AFCI, GFCI and GFPE is additionally frustrating.

You are right, I meant to edit that part also, sorry: They are GFCI breakers. Nothing involved in this discussion uses AFCI. The rooftop outlets are all GFCI with weatherproof covers. I think you make a good point about the heat cable being previously exposed to a high-overcurrent. I shall have my electrician replace all runs of the heat tape.

OK guys, I had a qualififed electrician fix the problems. I wanted to let you know what he found. Also, I have to correct information I've told you from the start.

Hello, I have tripping issues on a snow melting system in a commerical building. The voltage is 120/208. This snow melting system has 4 separate heater circuits, each 120V, each on its own GFCI Breaker (20 A). The 5th AFCI Breaker which has no trouble at all is for the control equipment (which is just a temp monitor and Normally Open Contactor). Here is the panel schedule for the breakers in question:
1 (20 A SP Standard breaker) - Rooftop GFCI outlets
3 (20 A SP Standard breaker) - Rooftop GFCI outlets
5 (20 A SP Standard breaker) - Rooftop J-boxes & LED Lighting
7 (20 A SP Standard breaker) - Rooftop J-boxes
9 (20 A SP GFCI Breaker) - Heat tape
11 (20 A SP GFCI Breaker) - Heat tape
13 (20 A SP GFCI Breaker) - Heat tape
15 (20 A SP GFCI Breaker) - Heat tape
17 (20 A SP GFCI Breaker) - Controller

These were the symptoms:
9 will hold all day and all night, no problems with this circuit. 11 will trip as soon as you energize it, same for 13. 15 will hold for about 30 seconds, then trip. 17 is the controller and no problems with this circuit. Circuits 9-15 go out to a NC Contactor then up to the roof to be disticuted. The contactor coil is controlled by the temp monitor and is energized when the conditions are right for the sensors, closing the contacts and energizing the heat tape runs.
The reason i included information about circuits 1-7 is because if I shut off 1-7, then 11-13 will hold. 15 will still trip after 30 seconds or so. When i energize 1-7, 11 and 13 will trip.

This was my original thought:
I am thinking that these rooftop devices are all sharig neutrals with my heat tape? I'm not sure about this, but was looking for some ideas out there? Please let me know what you think or if you need more information.

This is what my electrician's meter readings were:
Line: A - 121 V AB - 207 V
B - 120 V BC - 208 V
C - 119 V AC - 208 V

CKT 1 - 0 A
3 - 0 A
5 - 1 A
7 - 0 A
9 - 57 A
11 - 59 A
13 - 39 A
15 - 12 A

Needless to say, he was quite concerned with these numbers

This is what was found to be the problem:
-There was absolutely no grounding installed in the rooftop j-boxes. The original contractor did not ground anything up there!
-The heat tape neutrals were being shared with other circuits (1-7)
-Not only were the neutrals being shared, the neutrals from the heat tape circuit were landed on the neutral bus and the neutrals for other circuits were landed on the GFCI breaker
-The heat tape cable terminations were not made up correctly. The contractor did not follow the manufacturers installation instructions for terminating the cables.

What he did to fix the problem:
- Pulled in new neutrals to where needed
- Pulled in ground wire to all jboxes and loads
- Sorted out the mixed up neutrals in the panel and landed them correctly
- Remade the heat cable terminations and megged them
- Tested the system

I'm glad its over with! Thank you guys for your help especially Mr. Watson. I truly respect you for setting me on safety and getting it looked at by a professional. I appreciate your concern in the matter of safety. Thanks again everyone

Ok new correction (sorry!) the breakers are GFPE rated to trip at 30 mA leakage current.

Originally Posted by ben jacks

Namely the GFCI trips at 6ma and a GFP trips at a 60 ma leakage fault.

I disagree with your claims about 120V 30A or less GFEP Breakers. Where are you getting your information from "Ben Jacks"?

A combination AFCI breaker has a GFE componant.

120V GFEP Molded Case Circuit Breakers 30A and less = threshold trip at 30 mA, NOT 60 mA! Standards for Compliance are trip sensitivity for 30 mA for GFEP!!! UL Standard 1053. (CSA C22.2 No. 144).



De-icing cables on roof require GFE protection - to protect from fire caused by failure heat cable equipment.

GFCI is Class A protection (5mA) which allows for a tolerance of +/1 1mA(4-6 mA). UL Standard 943 (CSA C22.2 No. 144).

The story has now changed again regarding identification of equipment, and I still do not trust the latest version. This is obviously a DIY and I'm getting out of the dubious and obvious loopy "ever-changing-story", but I do not believe the OP is off-the-hook, not even close. Re-using or continuing to use circuit breakers that failed to trip when 200% and 300% of load, and one in particular which wouldn't trip until after 30 sec. of 300% of load and "#9 will hold all day and night" (yet supposedly had 59A load measured upon it but was labeled a 20A MCCB!) is IMO not only stupid, its potentially criminal!!! This guy STILL doesn't know if he has GFCI MCCBs, AFCI MCCBs or GFPE MCCBs on his heat tape circuits. No matter what, THEY SHOULDN'T BE TRUSTED, but on the otherhand, AFAIK, neither should the OP or anything he's said now, about anything, since he's contradicted himself so very many times on basic identifications. At this point I'm doubting a qualified, licensed electrician from a legitimate electrical contractor was even involved, evaluated, tested, and corrected anything; and am concerned someone is apt to be killed or injured. This is a poly-phase electrical system and some unqualified idiots have been allowed to tinker with it. All and all a VERY BAD THING.

Originally Posted by ben jacks

I agree with you on the overall confusion the OP is caught up in, but to throw additional suppositions into the mix seems to be what is happening here. I ask for identifiable equipment and installation conditions to find out what exists and that is all that can be done to find out if the OP is forthcoming with better details. CSA does not enter into the picture and who cares if the AFCI has a GFP component. So does a GFCI. Let the OP respond to what I ask...Okay?

YOU SAID GFPE trip threshold was 60 mA just over 3 hours ago!!! IT IS NOT!!! The trip threshold for GFPE is 30 mA. How can you POSSIBLY be "helping" an OP that doesn't know what kind of circuit breakers are in his polyphase commercial panel in the first place?!?

What about what YOU said in the portion of the post I quoted WAS WRONG, did you FAIL TO UNDERSTAND "ben jacks"???

Where do you get "your information" from? Why would you claim GFPE trip threshold is 60 mA? How is disinformation helpful to anyone?

Originally Posted by ben jacks

At least you are getting some feedback, but it is hard to give answers from a sofa. Your latest information needs a lot more detail for anyone to give a decent suggestion to resolving a system installation that is riddled with problems that are described so far.

First up, there is a major difference between a GFCI and a GFP protection device...Namely the GFCI trips at 6ma and a GFP trips at a 60 ma leakage fault. The heater circuits are required to be on GFP breakers and not GFCI's.

OK well since now I'm an idiot and the problem is solved anyways, I won't be posting here anymore.

Originally Posted by H.G. Watson, Sr.

YOU SAID GFPE trip threshold was 60 mA just over 3 hours ago!!! IT IS NOT!!! The trip threshold for GFPE is 30 mA. How can you POSSIBLY be "helping" an OP that doesn't know what kind of circuit breakers are in his polyphase commercial panel in the first place?!?

What about what YOU said in the portion of the post I quoted WAS WRONG, did you FAIL TO UNDERSTAND "ben jacks"???

Where do you get "your information" from? Why would you claim GFPE trip threshold is 60 mA? How is disinformation helpful to anyone?

Same old Watson ... Brian's recent post about those types of posts seems to have gone unheeded.

Originally Posted by John Schneider

OK well since now I'm an idiot and the problem is solved anyways, I won't be posting here anymore.

John,

Ever since Watson started posting here there has been discord and disharmony in the universe.

Please disregard Watson's lack of ability to communicate without ranting or degrading others.

Stay and continue to post as needed, one bad apple does not spoil the entire barrel.

Originally Posted by John Schneider

OK well since now I'm an idiot and the problem is solved anyways, I won't be posting here anymore.

Hmmm. You claimed before it wasn't YOU (the unqualified idiot who installed the heat cable to your electrical system) but another "contractor".

If the truth is that YOU did the wiring errors abounding, unsafe, incorrect, dangerous, installation, then, yes, you are an idiot. Especially with poly-phase service.

And no, the "problem" is not necessarily "solved", just perhaps the one of the indications/symptoms of your system's "symptoms" or one of many "indications" of your wiring error problemS, is no longer presenting itself.

There are other problemS, not yet resolved according to your limited, ambiguous, constantly edited, and ever-changing fact-set.

Originally Posted by H.G. Watson, Sr.

At this point I'm doubting a qualified, licensed electrician from a legitimate electrical contractor was even involved, evaluated, tested, and corrected anything; and am concerned someone is apt to be killed or injured. This is a poly-phase electrical system and some unqualified idiots have been allowed to tinker with it. All and all a VERY BAD THING.

Originally Posted by John Schneider

...This is what was found to be the problem:
-There was absolutely no grounding installed in the rooftop j-boxes. The original contractor did not ground anything up there!
-The heat tape neutrals were being shared with other circuits (1-7)
-Not only were the neutrals being shared, the neutrals from the heat tape circuit were landed on the neutral bus and the neutrals for other circuits were landed on the GFCI breaker
-The heat tape cable terminations were not made up correctly. The contractor did not follow the manufacturers installation instructions for terminating the cables

"the original contractor", "the contractor" is the UNQUALIFIED IDIOT I was refering to! This WAS OBVIOUS.

And, assuming ANYTHING John Schneider has presently left in its current (as of this posting) state on this entire topic thread is or was true, there can be NO DOUBT that WHOMEVER wired these circuits WAS and IS an UNQUALIFED IDIOT.

Originally Posted by John Schneider

You are right, I meant to edit that part also, sorry: They are GFCI breakers. Nothing involved in this discussion uses AFCI. The rooftop outlets are all GFCI with weatherproof covers. I think you make a good point about the heat cable being previously exposed to a high-overcurrent. I shall have my electrician replace all runs of the heat tape.

OK guys, I had a qualififed electrician fix the problems. I wanted to let you know what he found. Also, I have to correct information I've told you from the start.

Hello, I have tripping issues on a snow melting system in a commerical building. The voltage is 120/208. This snow melting system has 4 separate heater circuits, each 120V, each on its own GFCI Breaker (20 A). The 5th AFCI Breaker which has no trouble at all is for the control equipment (which is just a temp monitor and Normally Open Contactor). Here is the panel schedule for the breakers in question:
1 (20 A SP Standard breaker) - Rooftop GFCI outlets
3 (20 A SP Standard breaker) - Rooftop GFCI outlets
5 (20 A SP Standard breaker) - Rooftop J-boxes & LED Lighting
7 (20 A SP Standard breaker) - Rooftop J-boxes
9 (20 A SP GFCI Breaker) - Heat tape
11 (20 A SP GFCI Breaker) - Heat tape
13 (20 A SP GFCI Breaker) - Heat tape
15 (20 A SP GFCI Breaker) - Heat tape
17 (20 A SP GFCI Breaker) - Controller

These were the symptoms:
9 will hold all day and all night, no problems with this circuit. 11 will trip as soon as you energize it, same for 13. 15 will hold for about 30 seconds, then trip. 17 is the controller and no problems with this circuit. Circuits 9-15 go out to a NC Contactor then up to the roof to be disticuted. The contactor coil is controlled by the temp monitor and is energized when the conditions are right for the sensors, closing the contacts and energizing the heat tape runs.
The reason i included information about circuits 1-7 is because if I shut off 1-7, then 11-13 will hold. 15 will still trip after 30 seconds or so. When i energize 1-7, 11 and 13 will trip.

This was my original thought:
I am thinking that these rooftop devices are all sharig neutrals with my heat tape? I'm not sure about this, but was looking for some ideas out there? Please let me know what you think or if you need more information.

This is what my electrician's meter readings were:
Line: A - 121 V AB - 207 V
B - 120 V BC - 208 V
C - 119 V AC - 208 V

CKT 1 - 0 A
3 - 0 A
5 - 1 A
7 - 0 A
9 - 57 A
11 - 59 A
13 - 39 A
15 - 12 A

Needless to say, he was quite concerned with these numbers

This is what was found to be the problem:
-There was absolutely no grounding installed in the rooftop j-boxes. The original contractor did not ground anything up there!
-The heat tape neutrals were being shared with other circuits (1-7)
-Not only were the neutrals being shared, the neutrals from the heat tape circuit were landed on the neutral bus and the neutrals for other circuits were landed on the GFCI breaker
-The heat tape cable terminations were not made up correctly. The contractor did not follow the manufacturers installation instructions for terminating the cables.

What he did to fix the problem:
- Pulled in new neutrals to where needed
- Pulled in ground wire to all jboxes and loads
- Sorted out the mixed up neutrals in the panel and landed them correctly
- Remade the heat cable terminations and megged them
- Tested the system

I'm glad its over with! Thank you guys for your help especially Mr. Watson. I truly respect you for setting me on safety and getting it looked at by a professional. I appreciate your concern in the matter of safety. Thanks again everyone

Saving the latest version so the topic thread can still "speak for itself" even if he deletes or edits the contents of the posts, yet again!

And yeah, I'm more than a "bit" concerned that "ben jacks" is in the mix again spouting disinformation, esp. after his pre-Christmas spouting off about the heat cables having to be GFCI protected. As his post presently reads (after he was "called on it" and edited the crap out of it) it now refers to GFEP, but it didn't originally!

Originally Posted by ben jacks' edit remark

Last edited by ben jacks : 12-20-2010 at 01:31 PM. Reason: oops, GFPE required, not [210.8] GFCI (deleted)

So now that he's carrying on with more disinformation, claiming GFEP trip threshold is 60 (Sixty) mA, especially with a HAZARDOUS described situation, which should NOT be "handled" DIY on the "net", yes, its upsetting to say the least.

As far as when disharmony or discord first occured on this or the preceeding board (IN-dot-com) that long pre-dates MY participation, and can be found with your own, Jerry Peck! Talk about those in glass houses throwing stones!