Heat Tape- 120V or 240V to prevent ice accumulation?

[plowhog]

Ice sliding off the roof of my metal garage damages the gutter every year. I want to prevent this in the future.

The building is insulated, but the overhanging eave is not. It's the roof area above this eave where I accumulate ice, which is within 3 feet of the gutter. Farther up the roof is not so much of a problem. My roofer can install heat tape in a WWWW pattern to protect this area.

Platt Electric has Raychem heat tape in both 120V or 240V versions. The 240V version is $23/ft vs 120V version at $7/ft. Some versions are limited on total distance but I could split the total run into two separate runs that meet in the middle. Total footage is going to be about 280 feet after all the patterns in a W fashion are done.

Q- does anyone have experience with the pros and cons of 120V vs 240V? I have to run special electrical outlets anyway, so the added cost for heavier wire for 240V won't be that much. It's the heat tape itself that is much more expensive in 240V-- about $2,000 for 120V vs $6,000 for 240V.

Ideas?

https://www.platt.com/p/0156232/nvent-raychem/heat-cable-250-6w/715629000187/rcmh612250

https://www.platt.com/p/2024093/nvent-raychem/self-regulating-heating-cable-208-277v/715629421203/rcm5xle2cr

 

[Topzide]

I think the reason for the 2 voltages are, in Europe it's 240. Get the 120, you'll be fine.

 

[BlueKnife]

With the amount of money you're considering spending on heat tape, you may be able to fix the problem. Heat tape is a bandaid fix. What is the roof pitch?

 

[grsthegreat]

Im an electrician and have installed lots of heat tape. There are 3 differences in raychem tape. First is wattage per foot, second is total length, and finally is it self regulated or not.

The first one you listed, which i pay about $6/ft, is self regulating and is 6 watts per ft.. max 250’ per circuit

The second one you listed, which i pay about $11/ft and its self regulating. But its meant for use inside pipes, grease traps, etc. not meant for gutters.

Platt also sells a 6 watt per foot, 240 v heat tape for about $7/foot. Up to 400 ft run per circuit. This is meant for gutters.

You need to run it like a bunch of WWW and run a length thru the gutter and thru downspout

You also need a special type of personal gfci rated 30ma GFCI breaker. This allows a higher trip rating than standard gfci

 

[grsthegreat]

Self regulating tape is more expensive to purchase, but saves $$$$ over time cause it basically shuts the section that doesnt need to melt snow while powering areas that do need to melt snow.

 

[plowhog]

Self regulating tape is more expensive to purchase, but saves $$$$ over time cause it basically shuts the section that doesnt need to melt snow while powering areas that do need to melt snow.

That is very interesting, thank you.

Also did not know about a special GFCI device. The roof pitch is 4:12.

 

[grsthegreat]

I generally use winterguard wet.

WinterGard Wet Self-Regulating Heating Cable

nVent RAYCHEM WinterGard Wet self-regulating trace heating cables provide energy efficient and easy to use solutions for pipe freeze protection and roof and gutter de-icing.

www.nvent.com

 

[grsthegreat]

https://morelectricheating.com/media/assets/product/documents/Raychem_Wintergard_Wet_Roof_and_Gutter_Deicing_Design_Installation_Guide.pdf

 

[plowhog]

Very helpful, thanks. I have a downspout on each end of the gutter, giving me the option to do two 120V runs, one up each downspout meeting in the center. If 120v need to split it up due to limits on total footage run.

My installer recommends looping the bottom of the "W" pattern down into the gutter to prevent gutter ice. But, it looks like Raychem recommends running a single additional straight piece which lays in the gutter. That would add a 3rd circuit if one is dedicated inside the gutter only.

Q- have you typically run the additional straight piece in the gutter, or just let the bottom "tails" from the W pattern go into the gutter?

 

[grsthegreat]

I loop the tails into the gutter and run a piece in the gutter and down the downspout. Ill take a picture and post later. I almost always use 240v tape myself, as its only about $1 a foot more than the 120, and im not screwed up using more length than i thought i would need.

 

[grsthegreat]

This is over my garage. I brought feeder wire thru soffit and into j box. Then i took 2 heat tape feeders out, one went down the downspout and thru the underground drain to daylight. The other went on eave to end, then looped back thru gutter.

I didnt notice the crappy trip paint job until i took this picture….guess ill be touching up some paint when it warms up. Its 27° today.

 

[grsthegreat]

This is the breaker i used. Its an equipment protection ground fault rated, 30mv.

Sometimes the breaker is as expensive as the tape.

 

[plowhog]

Just circling back to comment that my heat tape is installed, also some snow guards to prevent sliding ice and snow from stripping it off where it has been fastened. I appreciate all the positive comments and help.

I used 230V Raychem/nvent Wintergard wet, one segment up a downspout then across the metal roof. The other segment is in the gutter and goes down the other downspout.

I added a new electrical subpanel very close to the downspout location where both heat tapes emerge. Got very lucky as I already had a pipe through the slab that was perfectly located to add it. Added a dual gang bell box on the outside and a metal NEMA enclosure on the inside with a 230V contactor with 120v coil. Each heat tape is connected to a 20amp GFCI breaker.

I added a simple Dayton on/off temperature control, with an external temp sensor, and I also added an indicator light to let me know when it is active. I set the Dayton to activate about 29F and turn off at 32F. I may adjust that up/down as I get some experience with it.

So far all seems good. I've put an amp probe at each of the two breakers and max amperage draw so far is only 6amps at 20F outside temp.

The flaw is that it runs and uses electricity every time the temp gets low enough, whether ice and snow is present or not. Of course I can flip the breakers to deactivate it-- at least when I am around to do that. I might add more sophisticated snow sensors in the future but this was already a high dollar ($$$$) project.

 

[grsthegreat]

Snow sensors are nice, but spendy. I cheaped
out and added lighted 240 switch on

mine.