Voltage on gas pipe to boiler - newly qualified question!!

[BrightSparkPaul]

Hello all, be gentle I am newly qualified and this is my first post! I have a customer who cannot get their boiler serviced due to a 5 volt current on their gas pipe when the upstairs lighting circuit is energised. All the supplemental and equipotential bonding seems ok, tests are within limits when the circuit isn't energised. There are a few issues with labelling on the CU but other than that all seems to check out OK. Is my best way forward to get at all the wiring and check for some sort of contact here? No obvious contact in visible places and the pipes are not showing any voltage downstairs. Can only assume that somewhere the lighting circuit is 'leaking' somewhere. Any advice on how some of you guys would proceed would be most welcome!

 

[jeremy]

5V between an "earthed" pipe and what? If the gas pipe has a voltage or pd between it and earth then the pipe isn't earthed, or the I'm guessing induced voltage would disappear to earth. I would double and triple check all bonding, not just visual, but test continuity.

 

[Golden_Boy]

5V between an "earthed" pipe and what? If the gas pipe has a voltage or pd between it and earth then the pipe isn't earthed, or the I'm guessing induced voltage would disappear to earth. I would double and triple check all bonding, not just visual, but test continuity.

My point EXACTLY....

 

[jeremy]

They (whoever they are) say that " every day's a school day". Doubly true today. I've learnt that not only having a 3 week break then returning to work at full speed will make your back, legs, and hands ache, but also that the term "intrinsically" refers to explosive atmospheres. I should have known that with my fartypants!

 

[richardsolway]

get a volt stick, rub it very fast on your leg and hey presto......it lights up. They are not a true instrument and should not be used to prove dead or otherwise. Yes i do have one and they are ok for visual indication but really don't trust it. They can light up for many reasons. (REF: past 13 years experiance).
Plumbers........know as much as bt engineers and meter fitters at times!