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Thread: Box Bonding
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09-14-2010, 06:03 PM #1
Box Bonding
Is there a reason this metal junction box would not be required to be bonded to the ground wires? The electricians that did it are very reputable, but I can't see why it isn't bonded.
The wires are for an electric snow melt system. It is line voltage as far as I can tell. The ground wire at the bottom of the photo was not attached to anything.
Also, is snow and ice melting wiring required to be protected by a GFCI breaker?
Similar Threads:Jim Robinson
New Mexico, USA
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09-14-2010, 06:28 PM #2
Re: Box Bonding
Reputable? Reputable contractors, like all of us, make mistakes, but ... there are more "mistakes" in there than just that, and while "the contractor" may well be "reputable", 'a reputation is only as good as the poorest worker'.
Also, is snow and ice melting wiring required to be protected by a GFCI breaker?
Yes and no, but in that photo ... No.
- From the NEC: (bold and underlining are mine)
- - 210.8 Ground-Fault Circuit-Interrupter Protection for Personnel.
- - - FPN: See 215.9 for ground-fault circuit-interrupter protection for personnel on feeders.
- - - (A) Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specified in (1) through (8) shall have ground-fault circuit-interrupter protection for personnel.
- - - - (3) Outdoors
- - - - - Exception to (3): Receptacles that are not readily accessible and are supplied by a dedicated branch circuit for electric snow-melting or deicing equipment shall be permitted to be installed in accordance with 426.28.
- 426.28 Equipment Protection.
- - Ground-fault protection of equipment shall be provided for fixed outdoor electric deicing and snow-melting equipment, except for equipment that employs mineral-insulated, metal-sheathed cable embedded in a noncombustible medium.
That looks like it fails the 'GFCI not required' test for a couple of reasons.
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09-14-2010, 06:39 PM #3
Re: Box Bonding
Where's the metal-sheathed cable? Would still require GFCI for equipment protection, but that's cable run through emt, emt not part of the cable sheath, apparently going underground for protection of heat cable - box and emt should be bonded,
But this is hardwired (? needs terminals can't jamb multiples in one connector and call it good) would still require GFCI for personnel protection don't see a cord & plug or a receptacle anywhere to meet the exception JP posted.
Where's the exception? Everything you posted indicates GFCI protection of personnel (4-6 mA) is required, one exception for less than class A (equipment level not personnel) requires equipment (wiring method AND receptacle connection) not in place here, otherwise GFCI protection required for personnel, according to what JP has posted.
Last edited by H.G. Watson, Sr.; 09-14-2010 at 06:53 PM.
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09-14-2010, 07:01 PM #4
Re: Box Bonding
Hardwired through a relay switch, but there is no GFCI protection at the switch that I can see.
I can't tell what brand it is, but I'm putting it down as needing GFCI protection, unless they can show otherwise.
They have never used it, and don't even know if it will work or not. It was just connected about two months ago after being installed ten years ago.
Conduit is PVC. I forgot to mention that, but it doesn't change anything for the box that I'm aware of.
Jim Robinson
New Mexico, USA
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09-14-2010, 07:02 PM #5
Re: Box Bonding
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09-14-2010, 07:39 PM #6
Re: Box Bonding
Jeez haven't those guys heard of distribution blocks and ground blocks. For what it is worth those cables are TXLP heat cables. Outer sheath is PVC, then a metal sheath wraps the bare ground and insulated XLP copper conductor. The red wires are the xlp insulated solid copper conductors and the grounds are stranded.
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09-14-2010, 07:52 PM #7
Re: Box Bonding
Sorry I have to make a correction to my previous reply
Those are not the TXLP heat cables those are the "lead" wires that are spliced to the heat cables at the heated area. Only been around a few of these type systems and my memory failed me again.....
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09-14-2010, 07:54 PM #8
Re: Box Bonding
Least we forget ... they have conduit fill problems, and, if those conduits are longer than 24" they have major derating problems too.
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09-14-2010, 07:59 PM #9
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09-15-2010, 08:45 AM #10
Re: Box Bonding
Jerry Peck,
This is what I was addressing (and disagreeing with) as YOU stated in your first response post:
See Jerry, when you start off quoting a snipped specific question
"is snow and ice melting wiring required to be protected by a GFCI breaker" and respond: ", but in that photo, No."
Comes across as being a SPECIFIC and DEFINITIVE RESPONSIVE DECLARATION.
No misunderstanding that.
You followed with quotes of sections of code articles, THEN made this ambiguous (and even quoted yourself now) observation (emphasis mine):
That looks like it fails the 'GFCI not required' test for a couple of reasons
You did not indicate that NOT HAVING GFCI protection was one of the thiings wrong either, nor which level of GFCI protection was, or IF IT WAS required, specific to the described and photographed installation as indicated you were addressing regarding the OP's question.
Jerry, You said NO as in: THIS installation as photographed (and described) did NOT require GFCI protection, this indicates NO to GFCI protection for personnel AND NO to GFCI protection for equipment! To which, I disagreed.
If you MEANT to later CONTRADICT or reverse your opening statement on the subject or NEGATE the earlier determative declaration of "NO," it was NOT required for THIS installation, you did not do so! You made reference to an appearance of failing an ambiguous "test", whatever that "test" was meant to be, and not that it DID actually fail whatever that "test" was! You did not say that GFCI protection was indeed required, nor did you say required GFCI protection was to be Class A (personnel) or protection of equipment level.
Hence my post.
The "...looks like..." language near the end of your post did not reverse your earlier OPPOSITE declaration.
It should be noted, that something is lacking in the description and photo for it to be a complete system.
I suspect power from the panel is not at the photo. Something integral seems to be missing between power from the panel and the heat cabling to control when electricity will be worked and when it will not be worked, be it timer, switch override, temperature sensing logic circuit, relay, safety fuses, shunt, etc. Often separate zones also. That location may have cord & plug/GFCI receptacle, fed GFCI dead front, or supplied via remote panel with gfci/ocpd for equipment protection or Class A (for personnel). (edited later to add for clarity, or in integral protection of equipment at line volt controller).
Last edited by H.G. Watson, Sr.; 09-15-2010 at 12:16 PM.
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09-15-2010, 10:07 AM #11
Re: Box Bonding
I suspect power from the panel is not at the photo. Something integral seems to be missing between power from the panel and the heat cabling to control when electricity will be worked and when it will not be worked, be it timer, switch override, temperature sensing logic circuit, relay, safety fuses, shunt, etc. Often separate zones also. That location may have cord & plug/GFCI receptacle, fed GFCI dead front, or supplied via remote panel with gfci/ocpd for equipment protection or Class A (for personnel).
I'm drawing a blank on the gfci ... but I do not think that class A works on these systems....nuisance trip but I'm just not recalling...
Edit ... the only thing that is not looking correct to me is the size of the transformer that almost looks like a big multi contact relay. I also do not remember all that splicing. It's almost like the equipment isn't correct for the number of cold leads. Maybe they spliced to another jb somewhere with another relay or transformer???
Last edited by Roger Frazee; 09-15-2010 at 10:23 AM.
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09-15-2010, 10:56 AM #12
Re: Box Bonding
I am not familiar with a Listed lower voltage "system" that would contain a field-installed raw componant stand-alone "transformer". A listed "power supply" Such as a "Class 2" as a part of a listed "system", for control and sensors perhaps, but not the use of a raw "transformer". Power closed prior so the "transformer" is not "working power" 24/7 should it be a power limited system. LV communications and control wiring would/should be separated from Line Voltage wiring.
I cannot see beyond the cables present to make any determination as to what that is as far as what may or may not be mounted on the backside of the pictured cabinet. It seems to me there wouldn't be sufficient depth/width/height to allow for much of anything regarding a power supply in that unviewable area. Frankly I assumed it was a switch/relay, Control Sensor mount for a contactor panel, etc.
I don't recall the OP indicating this was a pavement snow/ice melting system, do you suppose this might be for a Line voltage roof/gutter snow/ice melting system?
IIRC the longest warranty for cable systems is about 10 years. IIRC shortening the leads is not permitted as they are precise as are the heat cables. Aren't there green ground leads for TXLP Heating Cable Systems?
http://www.warmzone.com/SnowMelting/...stallation.pdf
Gutter/roof snow melt: http://www.orbitmfg.com/pdf/Instruct...er%20Cable.pdf
Snow Switch example http://www.chromalox.com/catalog/res...MOD-EUR-5A.pdf requires 24VAC Class 2 power supply customer supplied.
Control with integral GFEP example: Automatic Snow/Ice Melting System Control. APS-4C Snow/Ice Melting Control - Environmental Technology, Inc.
Another snow/ice melting control primarily for gutters & downs:
http://www.warmzone.com/diagrams/ETI-GIT-4.pdf
Above also contains some UL standard numbers and NEC references (various editions, as vintage of documents vary).
Whatever the case (pavement, LV control, roof gutter line voltage, etc.), something(s) is(are) obviously missing for it to be a proper "system" for control/operation, from the photo and descriptions from OP.
GFEP for wet is required somewhere in either case, Ground Fault protection for persons may also be required, possibly at outlet to PS.
Last edited by H.G. Watson, Sr.; 09-15-2010 at 12:11 PM.
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09-15-2010, 01:36 PM #13
Re: Box Bonding
I don't recall the OP indicating this was a pavement snow/ice melting system, do you suppose this might be for a Line voltage roof/gutter snow/ice melting system?
Looking at the warmzone links I'm not seeing anything like we have here on this thread and I too am now doubting that is a transformer in that junction box. Reason I said I thought it was is that the lead wires do connect directly to the transformer and that is shown in that warmzone link you posted.
But it doesn't look like the lead wires are connecting to individual terminals on a transformer but are obviously in a polaris type connecter and maybe a single wire (white) for each terminal of the polaris goes to that device mounted in the jb. Strange IMO.
Anyway I think I'll move on as OP has not returned and I'm just not familiar enough with these systems to be giving good advice.
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09-15-2010, 03:12 PM #14
Re: Box Bonding
I think everyone else got it.
That sure looks like a freight train headed toward you on those train tracks.
You have two choices: a) stand there and debate whether or not that really is a freight train going to run you over' b) accept that it sure looks like a freight train is going to run you over and get out of its way.
The choice is yours - you can debate its outcome after what looks like a freight train goes by.
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