Trace heating cable - testing issues

[JNJLAG]

Hi , Wondered if anyone can help , i currently install and test Trace Heating Cable on Mechanical Pipework for Frost protection . Recently our Clients are asking for a recordable test that states cable lengh of the circuit and a test to determine if there is a fault in the cable.
Currently using the Fluke 1503 to perform the resistance / continuity test for the client but have now requested this as an addition.

Any help would be greatly appreciated

 

[Lucien Nunes]

Is it not sufficient to give the end-to-end resistance of the cable?

Ah , i cannot perform end to end as the cable is installed on the pipe to a Max of about 130mts.

I think what was meant by 'end-to-end' was across the heating cable circuit from line to neutral, not physically from one end of the pipe run to the other. Each length of cable must surely be terminated in a way that brings the line and neutral connections together into the same box where they connect to the supply. That is where you would take the resistance measurement.

Is the cable printed with length markers that could be logged during install, and used to corroborate the measured resistance and resistance per unit length with the installed length? If those three parameters check out, and the insulation resistance is tested and proves good, then I think you have all reasonable data to claim it's intact short of a full visual inspection.

 

[timhoward]

The Fluke 1503 that is currently being used can also do the insulation resistance testing.
However, I think it doesn't have a 250v setting, only 500v and 1000v

It would be safe to join L and N together and test to the pipe at 500v but to play safe I wouldn't test L to N at 500v without the cable manufacturer's advice.
The equivalent Megger tester which also has a 250v (and 100v) range is probably the BM80, which regularly come up on ebay as the fashion is for all-in-one multi function testers these days.

 

[Lucien Nunes]

I wouldn't test L to N at 500v without the cable manufacturer's advice

It's a permanently-connected resistive load, so testing L-N with an insulation tester wouldn't yield any useful information anyway.