# Self Regulating Heat Trace Cable . Help.



## SPARKY_TORONTO (Mar 30, 2009)

Hey Guys,

I am installing self regulating heat trace cable on some Fire System pipes and drains for freeze protection.

The wires I am using is 5Watt/per ft 

Does anyone know the correct calculation for length of wire on a 15 amp circuit?

also what is the rule of thumb or calculation for how many wires too run on bigger pipe sizes? (i.e. 4" pipe one wire, 10" pipe two wires?)

Any tips from guys who have done frequent tracing? thanks a bunch.

:thumbup::thumbup:


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## wildleg (Apr 12, 2009)

I don't know the rules in canada, but if this is a life safety sprinkler other rules may apply (other than electrical code)


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## Cow (Jan 16, 2008)

Sparky,

you're best bet is to look up the literature for the particular brand and type of cable you're using. The Raychem and Chromolux products I've used in the past have had charts listing the max lengths at the different voltages for each of their products. They should also have some pictorials on how cables should be routed around different size pipes, T's, valves, etc as well.

If all else failed you could calc it yourself:

1800 watts x 80%(continuous load)=1440 watts max/circuit

1440/5 watts per foot=288 feet. At least this gives you a rough idea, just remember you may have some serious voltage drop at the end if you try and run it that far.

The best thing would be to find the manufacturers literature and go from there though.


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## 99cents (Aug 20, 2012)

Cow said:


> Sparky,
> 
> you're best bet is to look up the literature for the particular brand and type of cable you're using. The Raychem and Chromolux products I've used in the past have had charts listing the max lengths at the different voltages for each of their products. They should also have some pictorials on how cables should be routed around different size pipes, T's, valves, etc as well.
> 
> ...


 Self reg has inrush. Max run length is also dependent on ambient temperature. You guys are right, check the installation guide.


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## glen1971 (Oct 10, 2012)

What brand of trace are you using? There are some downloads available online that are a good tool for generating the amount of trace needed, the size of the breaker, and the expected currents. 
As you do more there are "rules of thumb" that many have developed that are a good guideline for installing it... For instance, I will typically limit my trace length to about 175' max. (typically 9-12 watt/foot range) and will not pull any wire smaller than #10 to any heat trace power kit..


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## CT Tom (Aug 10, 2014)

I use NuHeat

This is the link to their footage requirements.

http://www.nuheat.com/freeze-protec...ady-heat-trace-cable/#maximum-circuit-lengths


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## JHFWIC (Mar 22, 2012)

I installed some that said it would pull 5 watts per foot, the actual draw was 8 watts per foot.


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## SPARKY_TORONTO (Mar 30, 2009)

*Thanks to all.*

Thank you to everyone who took out time to reply.

Here is more info because some asked what manufacture and ambient temperature and all.

The installation is in the first level of a parking garage below a shopping mall so in the winter when door open and all it gets cold.

http://www.trm-kremco.com/Self Regulating Cable.pdf 
120v/15Amp circuits

One question no one was able to answer is how many runs do bigger pipes get 2-3 or one is sufficient how do you figure that out?

thanks for your time.


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## sparkywannabee (Jan 29, 2013)

I have used these pretty extensively on compressed air lines, valves, actuators, cylinders etc that were on these afterburners we had outdoors, heat trace would not work just by itself, had to use the plumbing kind of insulation on the lines with the heat trace stuffed in, wire tied or taped, around the cylinders, transducers etc we had sheetmetal boxes built to fit that we took off in the summers. You really need o wrap the solenoid valves with the tiny air passages in them more susceptible to freezing. i think we had 4 50' lines on a GFCI outlet through a 20 amp breaker, they seemed to get awfully trippy when it was wet.


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## glen1971 (Oct 10, 2012)

SPARKY_TORONTO said:


> One question no one was able to answer is how many runs do bigger pipes get 2-3 or one is sufficient how do you figure that out?
> 
> thanks for your time.


Here's what I usually do.. Haven't seen a calculation on it, just what I've found works with one design program I use..

Typically for 120 volt tracing I run:
1 tracer for piping up to 6" diameter
2 tracers for piping up to 12" diameter
3 tracers for piping up to 18" diameter

Anything above 18" pipe I'd be looking at 208 volt and piping that size is typically engineered too. And I'd be looking into the calculator for some of the larger pipe sizes..

Also, as another "rule of thumb" don't exceed 5 w/ft on fibreglass pipe..


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## don_resqcapt19 (Jul 18, 2010)

I don't know what the rules in Canada are, but in the US, heat trace for fire sprinkler systems, has to be specifically listed for use on fire systems. We are not permitted to use standard heat trace.


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## wildleg (Apr 12, 2009)

I wonder how many years of paying for the electric for the heat trace it's going to be before the owners start wishing they had just paid for a dry pipe system or an antifreeze system in the first place.


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## Jhellwig (Jun 18, 2014)

sparkywannabee said:


> I have used these pretty extensively on compressed air lines, valves, actuators, cylinders etc that were on these afterburners we had outdoors, heat trace would not work just by itself, had to use the plumbing kind of insulation on the lines with the heat trace stuffed in, wire tied or taped, around the cylinders, transducers etc we had sheetmetal boxes built to fit that we took off in the summers. You really need o wrap the solenoid valves with the tiny air passages in them more susceptible to freezing. i think we had 4 50' lines on a GFCI outlet through a 20 amp breaker, they seemed to get awfully trippy when it was wet.


They had a crappy air dryer there apparently. Most pneumatic equipment spec freeze ride air to 10 degrees below ambient to keep from having freezing issues.

I have only ever seen heat trace sold in lengths up to the ampcity rating. Most of the industrial stuff is rated for 20 or 30 amp.

The manufacturer will have specs for whatever style you bought and be able to tell you how much you need to install to obtain the needed tempature rise.


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## Cow (Jan 16, 2008)

wildleg said:


> I wonder how many years of paying for the electric for the heat trace it's going to be before the owners start wishing they had just paid for a dry pipe system or an antifreeze system in the first place.


Don't try to confuse us with common sense. We're here to run heat trace...:whistling2:


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## Mountain Electrician (Jan 22, 2007)

SPARKY_TORONTO said:


> Thank you to everyone who took out time to reply.
> 
> Here is more info because some asked what manufacture and ambient temperature and all.
> 
> ...


That would need to be engineered. 

http://www.pentairthermal.com/design-tools/online-tools/XL-ERATE/index.aspx


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## sparkywannabee (Jan 29, 2013)

Jhellwig said:


> They had a crappy air dryer there apparently. Most pneumatic equipment spec freeze ride air to 10 degrees below ambient to keep from having freezing issues.
> 
> I have only ever seen heat trace sold in lengths up to the ampcity rating. Most of the industrial stuff is rated for 20 or 30 amp.
> 
> The manufacturer will have specs for whatever style you bought and be able to tell you how much you need to install to obtain the needed tempature rise.


We had pretty decent refrigerant dryers in good working order, although I thought the desiccant types seem to work better. They were pretty far away from the RTO's and as comp. air temp drops more moisture comes out of it, even though it was dried fine at a higher temp, that is just the physics of it. We took that long run into account and had small wall hanging dryers, ingersoll rand, with pre and after filters right before air line left the building. From 70 to below 0 is a hell of a drop, moisture will come out, mac valves, damper actuators etc would freeze. We had to use torpedo heaters to get things thawed out and working. This winter was actually really mild, not too many issues but the one before, with the stupid polar vortex bs, I was outside more time than in. If we did'nt enclose around the trace with insulation or something, the little bit of heat it created would be lost. We just bought the stuff out of grainger, boss picked some up at lowes.


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## Jhellwig (Jun 18, 2014)

sparkywannabee said:


> We had pretty decent refrigerant dryers in good working order, although I thought the desiccant types seem to work better. They were pretty far away from the RTO's and as comp. air temp drops more moisture comes out of it, even though it was dried fine at a higher temp, that is just the physics of it. We took that long run into account and had small wall hanging dryers, ingersoll rand, with pre and after filters right before air line left the building. From 70 to below 0 is a hell of a drop, moisture will come out, mac valves, damper actuators etc would freeze. We had to use torpedo heaters to get things thawed out and working. This winter was actually really mild, not too many issues but the one before, with the stupid polar vortex bs, I was outside more time than in. If we did'nt enclose around the trace with insulation or something, the little bit of heat it created would be lost. We just bought the stuff out of grainger, boss picked some up at lowes.


 
I feel your pain. I delt with the same thing for a lot of years.

On the air dryer I should have said that it should run down to the ambient air that the device using the air is in, not where the dryer sits. If it is -10 outside your dryer had better be getting it below -20. I think our dryer here will get down to -30 in the winter. Dessicant cant do that.

I used to have to fight heat trace every winter because the place I worked for got rid of all the pm's to check it before it got cold. Every now and then the heat trace would be off or not working for some reason. Most of the time the insulation was ruined or saturated or they forgot about the 50 foot of pipe that got replace over the summer that froze and broke last year but no one thought to have insulation put back on it after it was heat traced. Or the pipe froze because the heat trace had been shut off because there was no thermostat and saftey didnt like it when the water turned to steam comming out of the eye wash stations. Then they would think that once I turned the heat trace back on it would thaw out quick. :no:


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## glen1971 (Oct 10, 2012)

I laugh hard when I get called because a pipe froze and there is no insulation on it.. Without insulation heat trace just helps out global warming... 

Had one site where an 8" Sch. 160 pipe froze enough to bubble the paint on it and they asked if the heat trace would have it thawed by morning - another good chuckle..


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## glen1971 (Oct 10, 2012)

sparkywannabee said:


> I have used these pretty extensively on compressed air lines, valves, actuators, cylinders etc that were on these afterburners we had outdoors, heat trace would not work just by itself, had to use the plumbing kind of insulation on the lines with the heat trace stuffed in, wire tied or taped, around the cylinders, transducers etc we had sheetmetal boxes built to fit that we took off in the summers. You really need o wrap the solenoid valves with the tiny air passages in them more susceptible to freezing. i think *we had 4 50' lines on a GFCI outlet through a 20 amp breaker*, they seemed to get awfully trippy when it was wet.


Forgive my dumb question, but north of the 49th we can put Heat Trace on a breaker with a 33 mA trip to avoid the nuisance tripping.. GFCI outlets are at 5 mA.. Are you limited to 5 mA ground fault installations in the US?


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## sparkywannabee (Jan 29, 2013)

glen1971 said:


> Forgive my dumb question, but north of the 49th we can put Heat Trace on a breaker with a 33 mA trip to avoid the nuisance tripping.. GFCI outlets are at 5 mA.. Are you limited to 5 mA ground fault installations in the US?


That was actually on my list of things to do, one of you guys had mentioned something about a breaker called GFPE, a higher trip just for stuff like this. I was going to install that in the panel and get rid of the GFCI outlet outside, just so many hours in a day. Than about 6 months ago I got a different job, the only thing outside here is the AC chillers, don't have to worry about dems in the winter.:thumbsup:


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## sparkywannabee (Jan 29, 2013)

glen1971 said:


> I laugh hard when I get called because a pipe froze and there is no insulation on it.. Without insulation heat trace just helps out global warming...
> 
> Had one site where an 8" Sch. 160 pipe froze enough to bubble the paint on it and they asked if the heat trace would have it thawed by morning - another good chuckle..


You are absolutely right, without insulation the heat dissipates into the atmosphere. We even used rags we tied up to get through till we could insulate, or on an actuator or something cause of its shape, but you have to have something.


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## sparkywannabee (Jan 29, 2013)

Jhellwig said:


> I feel your pain. I delt with the same thing for a lot of years.
> 
> On the air dryer I should have said that it should run down to the ambient air that the device using the air is in, not where the dryer sits. If it is -10 outside your dryer had better be getting it below -20. I think our dryer here will get down to -30 in the winter. Dessicant cant do that.
> 
> I used to have to fight heat trace every winter because the place I worked for got rid of all the pm's to check it before it got cold. Every now and then the heat trace would be off or not working for some reason. Most of the time the insulation was ruined or saturated or they forgot about the 50 foot of pipe that got replace over the summer that froze and broke last year but no one thought to have insulation put back on it after it was heat traced. Or the pipe froze because the heat trace had been shut off because there was no thermostat and saftey didnt like it when the water turned to steam comming out of the eye wash stations. Then they would think that once I turned the heat trace back on it would thaw out quick. :no:


Iowa winters are prolly worse than ours, seems like I went through all the stuff you did. I don't think dryers can dry air for a big temp drop down the line, they can only dry it at the temp it is at right than. Not sure why I thought desiccant was better than refrigerant, you are probably right about that. I just have bad memories of changing out desiccant, the damn pipe plug on the bottom would be so corroded I would have to drill and chisel it out just to get the desiccant out.


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## don_resqcapt19 (Jul 18, 2010)

glen1971 said:


> Forgive my dumb question, but north of the 49th we can put Heat Trace on a breaker with a 33 mA trip to avoid the nuisance tripping.. GFCI outlets are at 5 mA.. Are you limited to 5 mA ground fault installations in the US?


Our code requires the use of Ground Fault Protection of Equipment for heat tape. UL permits that type of ground fault protection to have trip points between 6mA and 100 mA. A typical 20 or 30 amp breaker with equipment ground fault protection will have a 30mA ground fault trip.


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