Volts running through water pipes

[SirStan2000]

I am currently doing a love job and found that the water pipes have 93.4v running through them? the problem i have is that this is intermittent, for about 5 mins at a time? so live for 5 mins then dead then live again? i wondered if anyone had advice before i take up floor and things. i thought maybe a problem with the boiler but as i was testing live we turned the boiler off at the spur and still had the volts, i have identified the circuit it is on, unfortunately the boiler is on the house ring. any ideas please? thanks in advance

 

[Vortigern]

What are you testing this voltage with if I may ask? And where are you testing i.e. from the pipe to what?
Maybe switch everything off at the mains, then process of elimination one circuit on at a time might help?

 

[James]

93v when measured against what?
if you are measuring a voltage between an earth cable and a pipe, it suggests that either the earth cable is not bonded correctly or the pipe is not bonded to earth.

what is the method of earthing at the property?

I would start by finding out what the Ze is to confirm you have a decent earth to the property in the first instance.

 

[Dustydazzler]

Lose N ?

 

[Vortigern]

Ok sorry gotta ask, what is a love job? And just an afterthought, could be a phantom voltage, have you got a drummond tester?

 

[ruston]

@Vortigern A love job is a freebie to a family member or a mate , up here it is anyway.

 

[Lucien Nunes]

Water can run through the pipes but volts can't run through anything. I take it you mean:
"I measured 93 volts between some pipes and something else"
If that other thing is a CPC or the MET or something supposedly earthed within the electrical installation, you've got two main possibilities:

a) The MET is earthed, but the pipes are not. Leakage from the installation to the pipes is raising their potential, possibly due to a disconnected CPC (in which case the leakage may be normal) or a fault from a cable to a pipe. Solution: find and fix the leakage source and / or missing CPC. Check whether the pipes should have been bonded anyway.

b) The pipes are earthed (or extraneous) but some or all of the installation is not. Leakage within the installation to the CPCs is raising part or all of the system to 93V above the potential that the pipes have found, but that's not immediately apparent as it's an equipotential and the problem is intermittent. However you should be able to catch it out with an abnormal N-E voltage soon enough. Solution: fix the broken CPC / EC / whatever.

Lose N ?

A loose neutral connection by itself won't make pipes live or the CPCs live relative to the pipes. OTOH, a high resistance connection in a combined neutral/earth conductor could very well raise the potential of supposedly earthed bits by 93V w.r.t true earth. But then, the L-N potential would have to be 230-93 = 137V and I expect they would have rather obvious symptoms of flickering lights and appliances shutting down.

could be a phantom voltage

One would think the C/H system would have at least some earthed components so that it should not normally be floating, so this would fall into my category a) above.

 

[Midwest]

Long story, but shortened here. As previously recounted, I came across a fault once, where plumber (son) got zapped when he touch copper pipes and bathroom wall. The wall was literally ‘live’; there was a voltage between wall and earth. Fault was intermittent.

The fault was eventually found; a previous owner of the property had nailed up some dado rail on the landing. One had nicked a strapper on two way for landing light. Note, on the landing, not in the bathroom.

Pooh happens.

 

[SirStan2000]

What are you testing this voltage with if I may ask? And where are you testing i.e. from the pipe to what?
Maybe switch everything off at the mains, then process of elimination one circuit on at a time might help?

hi mate, i'm using a fluke multi tester,and testing on the pipes to an earth source. i have identified the circuit and assume i will have to dig further under floors etc, but the it comes and goes every 5 mins just seems strange.

 

[Baddegg]

What’s connected to that circuit and when you say every 5 mins, do you mean that literally?

 

[snowhead]

If it's not something turning on and off every 5 or so minutes, it may be as Midwest and a nail /screw through a cable but only just touching a pipe and breaking down the connection as soon as it's made.
Maybe water making the connection and boiling off.

If the fault is on a Ring, break the ring down into sections.

 

[R-fur]

Turn off the power, run a temporary bond between MET and the pipe, restore power. 1 it will now be safe and 2 something may trip and give you a clue as to where the fault is.

 

[Megawatt]

I am currently doing a love job and found that the water pipes have 93.4v running through them? the problem i have is that this is intermittent, for about 5 mins at a time? so live for 5 mins then dead then live again? i wondered if anyone had advice before i take up floor and things. i thought maybe a problem with the boiler but as i was testing live we turned the boiler off at the spur and still had the volts, i have identified the circuit it is on, unfortunately the boiler is on the house ring. any ideas please? thanks in advance

Sirstan my advice would be for you to bond the pipe which will probably solve your problem

 

[SirStan2000]

Turn off the power, run a temporary bond between MET and the pipe, restore power. 1 it will now be safe and 2 something may trip and give you a clue as to where the fault is.

Thanks For That mate.

 

[davesparks]

Sirstan my advice would be for you to bond the pipe which will probably solve your problem

Bonding the pipe won't solve the problem, but it will possibly hide the problem.

 

[telectrix]

it could be a "ghost" ir induced voltage which the meter disharges when testing. . then 5 minutes later, it reappears.

 

[HappyHippyDad]

hi mate, i'm using a fluke multi tester,and testing on the pipes to an earth source. i have identified the circuit and assume i will have to dig further under floors etc, but the it comes and goes every 5 mins just seems strange.

As Vortigern mentioned, it would be a good idea to use a drummond test lamp or an analog tester just to rule out Ghost voltage. I measured 200V once (on a 19 core cable) and went into panic mode before measuring it with the drummond and realising it was ghost voltage.

 

[SirStan2000]

What’s connected to that circuit and when you say every 5 mins, do you mean that literally?

yep every 5 mins. it is like clock work, very strange unfortunately it is rewire-able fuses and the board needs updating but came across this problem and just wondered why it was intermittent before i cracked on with pulling boards up etc, the whole house is on one circuit lol and its a radial circuit to my shock so a lot of work to be done anyway. i now know that there is no main bonding to met and reading responses assume this is the reason? however it seemed quite high at 93.4v/ i am not a tester yet (defo doing that course this year)

 

[davesparks]

yep every 5 mins. it is like clock work, very strange unfortunately it is rewire-able fuses and the board needs updating but came across this problem and just wondered why it was intermittent before i cracked on with pulling boards up etc, the whole house is on one circuit lol and its a radial circuit to my shock so a lot of work to be done anyway. i now know that there is no main bonding to met and reading responses assume this is the reason? however it seemed quite high at 93.4v/ i am not a tester yet (defo doing that course this year)

Why are you shocked to find a radial circuit? It's a perfectly valid type of circuit.

A lack of bonding will not be cause of this, but bonding could make the symptom disappear.

 

[Pete999]

yep every 5 mins. it is like clock work, very strange unfortunately it is rewire-able fuses and the board needs updating but came across this problem and just wondered why it was intermittent before i cracked on with pulling boards up etc, the whole house is on one circuit lol and its a radial circuit to my shock so a lot of work to be done anyway. i now know that there is no main bonding to met and reading responses assume this is the reason? however it seemed quite high at 93.4v/ i am not a tester yet (defo doing that course this year)

When you say the Whole house is on 1 circuit and it's a radial, unsure of what you mean abd how you have come to this odd conclusion.