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Joined: 9/1/2009
Posts: 16
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I just bought a pipe heater that's a wire tape. The thermal switch is enclosed in thick clear plastic and the wiring is plainly visible with the green ground wire tied directly to the white neutral. Why is this done in a three wire system?
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Joined: 6/15/2007
Posts: 1894
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Really good question, T Mickleson. Clearly such an arrangement would be risking inadvertent trips if the heat trace equipment were served through a GFI device. Any current that happens to flow back on the ground wire would look to the GFCI as a ground fault. (It actually would be a ground fault in the technical sense, although it wouldn't be a danger to anyone.) I would think it quite likely that it would be connected to a GFCI protected receptacle. Would you please tell us the brand name and model of the tape assembly?
Bob Hoyer ...... Bremerton, WA
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Joined: 9/1/2009
Posts: 16
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The brand name is WRAP-ON®. This model is #31006, it's 12 watts and is 6' or 1,8m in length. It's CSA and UL approved. I got it at a Canadian Home depot. It's made in China 
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Joined: 6/15/2007
Posts: 1894
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Ah Ha! This relates to the earlier post on window condensation, doesn't it? As long as it is not on a GFI device, don't worry about it. It isn't going to cause any real problems. Still, it just ain't right. I'd suggest bringing it to Home Depot of Canada's attention. If you write a letter include a good photo with copy to CSA and UL. That six foot length is unusually short, but it sure suited your little trial situation well. We will be waiting to hear back on how it works out for the condensation issue. EDIT --- Just a quick add-on thought --- If you happen to have GFCI outlets in your kitchen, bath or garage (as newer codes would require) it would be interesting to plug that unit in just to see what happens. If it trips it should be reported to Home Depot, CSA and UL. We'd also like to know here on these forums whatever result you find. (I looked up WRAP-ON via the internet. Looks like they might be quite big in the heat trace business. Funny thing is that I was just involved in putting out a design that has a fair amount of heat tape to prevent frozen pipes on a Government facility. I will have to watch for the submittals and see if WRAP-ON shows up on this job.)
Bob Hoyer ...... Bremerton, WA
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Joined: 10/24/2007
Posts: 662
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IMHO:
Sounds like there's going to be some major recalls of Heat Tape by "Wrap-On" !
I would use it with one of those three-prong to two-prong adapters if you have it on a GFCI.
EDIT: Read on for an email from "Wrap-On"!
This community is the sum of of the knowledge of all.
Only we must communicate that knowledge to each other via this forum.
Participate, Teach and Learn.
Cordially,
Gerry
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Joined: 9/1/2009
Posts: 16
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The trial run proved a great reduction in condensation on the living room window. The heat tape is 6 feet while the window is closer to 7 feet and there's a buildup of condensation in that last uncovered foot. Bottom line, it works. I have a plastic clamp squeezing the heat tape's thermostat switch closed all the time. Otherwise it would never get cold enough to come on by itself. Another brand of heat tape has a sealed thermostat and I didn't buy it because it has to be bypassed but you can't get at the thermostat to do this. I couldn't tell you how it's wired either. My plan is to take this one apart and join the hot and neutral wires to a line cord while leaving the ground floating. There is no surface on this heat tape that has a ground capacity anyway, so I should be fine. Also the line cords you get with these things are very short making a window layout difficult to reach from a wall plug. While running, the heat tape is warm to the touch without feeling hot and when the heat is kept in the lower window area with a closed blind, the system seems to work just fine.
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Joined: 10/24/2007
Posts: 662
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In the interest of consumer safety, I had contacted "Wrap-On" and this is their reply...
Gerry,
The green ground wire from the cordset passes between the black and white wires of the cordset at the point that they are riveted to the thermostat circuit board. The green wire is attached to the ground braid of the heater wire by a crimp connector approximately three inches from the point that the black and white wires end.
If the white and green wires were shorted at any point in the cable, the cable would fail the hypot test which we perform on 100% of cables we produce as required by CSA, our primary listing agency.
If you have access to tmickelson I would ask you to privately suggest to him that he return the cable to me for inspection so I can verify his claim.
By the way, his application is not even close to the intended use of the cable and his proposed modification will not only void the Wrap-on warranty but also the CSA certification and cUL listing.
Thanks for your help.
Best regards,
Jerry Trakszelis
I hope this helps rest any doubts about the product.
TMickelson, I understand you wanting to be inventive with the basic product, but keep in mind the safety factor. Thermostats serve a purpose. In this case, the basic heat tape could possibly be modified by attaching a thermostat that would be better suited for your inventive application. I'm not suggesting you should, but rather consider other possibilities and the dangers involved.
Good Luck with thinking outside the box!
This community is the sum of of the knowledge of all.
Only we must communicate that knowledge to each other via this forum.
Participate, Teach and Learn.
Cordially,
Gerry
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Joined: 9/1/2009
Posts: 16
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I think I found the braid the same time you did. I should have not believed my eyes and did some elementary measurements. There's a law that covers that. I took the thermostat out completely and put a line cord directly on the heat tape. It runs slightly warm and it keeps most of the condensation, aka puddles, off the window and sill. If there's a better way, please let me know.
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Joined: 10/24/2007
Posts: 662
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The expense of better thermo-pane windows is daunting.
I would think about your "outside the box" idea more from the standpoint of safety.
If at all possible, at least a fuse, rated slightly above the tape's original rating, would help to improve safety. I personally would not want a heater of any type plugged in 24/7 without any sort of control or safety feature incorporated in it.
Depending on the power required, a simple fused plug, salvaged from a Christmas light string, attached to the line cord would be better than nothing.
I can not, off the top of my head, think of a thermostat that would be small and inconspicuous enough while keeping with the requirements of line voltage and current, to suggest it's use.
You "could" use a good clear packing tape to tape a piece of "J" channel, the type that may be used with paneling, to the glass making a mini-rain gutter and route that to a piece of clear aquarium tubing and down to a plant, keeping it watered.
But that's way-outside-the-box !
This community is the sum of of the knowledge of all.
Only we must communicate that knowledge to each other via this forum.
Participate, Teach and Learn.
Cordially,
Gerry
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