testing heat trace cable-help
- Thread starter pridelion
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mdshunk
Senior Member
- Location
- Right here.
Take an amp draw and compare it with the data tag on the cold lead.
Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
pridelion said:
Where is this cable located? The IR thermometer is not a bad idea.
quogueelectric
Senior Member
- Location
- new york
usually about 6 watts per foot
usually about 6 watts per foot
Figure out the total footage. the cable should be stamped how many watts per foot it is. If it is say 100ft at 6 watts per foot . Next find the voltage and do some simple math 600 watts /120volts =5 amps. Then turn it on and see if it draws 5 amps simple. Just like Marc said.
By the way I think meggering a heat trace cable is a bad Idea it is not an insulated cable it is a semiconductive material and will read a bad resistance every time. It is pointless
usually about 6 watts per foot
Figure out the total footage. the cable should be stamped how many watts per foot it is. If it is say 100ft at 6 watts per foot . Next find the voltage and do some simple math 600 watts /120volts =5 amps. Then turn it on and see if it draws 5 amps simple. Just like Marc said.
By the way I think meggering a heat trace cable is a bad Idea it is not an insulated cable it is a semiconductive material and will read a bad resistance every time. It is pointless
Last edited:
mdshunk
Senior Member
- Location
- Right here.
That was my knee jerk reaction, based on the old ceiling radiant heat Chromalox and other companies used to make. Then, I remembered that the newer stuff has a braided shield which is grounded (such as "Warm Tiles"), which would benefit from a megger test. With older heat trace cable, there's no ground to reference to megger it.quogueelectric said:
- Location
- Illinois
- Occupation
- retired electrician
A current measurement may not tell you much. A lot of the heat trace is self limiting and draws a lot less current as the temperature goes up. On a hot summer day it may draw almost no current if it is freeze protection trace.
Don
Don
Meggering heat trace is the preferred method for testing on new installs (or was a couple of years back) Oilfield gear is wrapped to beat the band to keep moisture out of the pipes in processing areas.
Per instruction from the manufacturers rep standing beside me, started at 500 VDC and bumped through the settings to 2500 VDC. When installed properly, all parts in the run should meg. Better to "blow up" your stuff than to have to come back later.
Would read whatever the manufacturers directions are, and follow that. Would think any reasonable install would stand up to 1000VDC meg test...but would call the brand name, of said gear, before testing!
Chromalox, or Raychem, would be my preferred brands, for dependability and harsh weather conditions.
Per instruction from the manufacturers rep standing beside me, started at 500 VDC and bumped through the settings to 2500 VDC. When installed properly, all parts in the run should meg. Better to "blow up" your stuff than to have to come back later.
Would read whatever the manufacturers directions are, and follow that. Would think any reasonable install would stand up to 1000VDC meg test...but would call the brand name, of said gear, before testing!
Chromalox, or Raychem, would be my preferred brands, for dependability and harsh weather conditions.
IEEE and Tyco-Raychem recommend meggering. Don't stop at 1000V, per the test procedures, many problems will not show up @ 1000V. You need to take it to 2500V. I have seen it pass at lower voltage and fail at higher. Twist the bus wires together, and check to braid. Then check from braid to pipe or something that is bonded to ground. Remember to get a hotwork permit if you are in a hazardous area, not just for the megger end, but the whole tracer.
Back to the OP, when the cable is warm, even though it is not energized, high ambient temps or high pipe temps will not give you the inrush current on self-regulating cables that you will get when everthing is cold.
Most plants do their heat trace PM's in October to get ready for winter. That way you have cold mornings, cooler pipes.
If you have to test in summer, can you put cold process in the pipes and turn on the trace to watch in-rush and to verify your GFEP does not trip?
Back to the OP, when the cable is warm, even though it is not energized, high ambient temps or high pipe temps will not give you the inrush current on self-regulating cables that you will get when everthing is cold.
Most plants do their heat trace PM's in October to get ready for winter. That way you have cold mornings, cooler pipes.
If you have to test in summer, can you put cold process in the pipes and turn on the trace to watch in-rush and to verify your GFEP does not trip?
- Location
- Bremerton, Washington
We have a run of self regulating heat tape under a concrete pier, its 277 with no GFPE. One day it caught on fire and got a lot of folks excited. It can only be worked on from a boat at low tide.
The little bit of self reg heat tape I have I can touch and it will be slightly warm but its only 3 watts per foot.
The little bit of self reg heat tape I have I can touch and it will be slightly warm but its only 3 watts per foot.
heat trace
heat trace
Hi, we use alot of heat trace at my company, usually I will feel it by hand, if your worried about being burned ( ours doesnt get too hot to touch for a second or two) a IR scan is a great way to go. otherwise do the amp draw. I believe the ratings vary but 10-15 watts per foot is common.
heat trace
Hi, we use alot of heat trace at my company, usually I will feel it by hand, if your worried about being burned ( ours doesnt get too hot to touch for a second or two) a IR scan is a great way to go. otherwise do the amp draw. I believe the ratings vary but 10-15 watts per foot is common.
quogueelectric
Senior Member
- Location
- new york
heat trace
heat trace
The last Install I did specifically stated not to be used on fuel lines so be sur e what you buy is appropriate for the application.
heat trace
The last Install I did specifically stated not to be used on fuel lines so be sur e what you buy is appropriate for the application.
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