Ok I have just opened a gym in Dublin Ireland but there is a small current running through the showers, about .1-.5 of a volt. I think it is a backlash of the neutral because even when I turn off the mains from the circuit box it still happens. I don't have any reset button on the board. I am open and didn't realise the problem till my first member touched it in his bare feet! (I have tested them but always in my runners) Oh and they are grounded by the way
Thanks
Mick

American here, so we will need to find a common language to get through some of the terminology.

Keep in mind, that it is current flow measured in amperes that will injure a person. More than 5 milli-amps across the heart can cause serious problems. This current flow can be at any voltage.

To receive a shock, there should be a circuit. So if someone is feeling a sensation in the feet, are they touching the shower head, valves, etc. to complete this circuit?

I am trying to find where the voltage is coming from, the cold water, hot water, drain line.

What do mean by not having a reset button on the board?

What test points are you using a voltmeter across?

Since you shut the main off, this helps prove that your electrical system is not causing the stray volts. It can be coming in from any other utility, so trying to locate it's source is the first step before determining the corrective measures needed.

Is your place of business part of a larger building that has other occupants/tenants? If so, is your electric main part of a larger electric distribution system?

What may need to happen is to "bond" (connect) any and all metal systems and utilities in the building, and connect to ground.

If you can offer more details and answer my questions we can see how we can help.

American here, so we will need to find a common language to get thru some of the terminology.

Keep in mind, that it is current flow measured in amperes that will injure a person. More than 5 milli-amps across the heart can cause serious problems. This current flow can be at any voltage.

To receive a shock, there should be a circuit. So if someone is feeling a sensation in the feet, are they touching the shower head, valves, etc. to complete this circuit?

I am trying to find where the voltage is coming from, the cold water, hot water, drain line.

What do mean by not having a reset button on the board?

What test points are you using a voltmeter across?

Since you shut the main off, this helps prove that your electrical system is not causing the stray volts. It can be coming in from any other utility, so trying to locate it's source is the first step before determining the corrective measures needed.

Is your place of business part of a larger building that has other occupants/tenants? If so, is your electric main part of a larger electric distribution system?

What may need to happen is to "bond" (connect) any and all metal systems and utilities in the building, and connect to ground.

If you can offer more details and answer my questions we can see how we can help.

Sorry I didn't make it clear, they are getting a shock when they touch the mixer valve to turn on or off the water. My point was that I never got it as I was always in runners and therefore not completing the circuit...

The water, and copper pipes are all conductors so they are all live.

SWome newer boards have a reset button which I have heard fixed the problem in one case where a sink was live but my board is old and doesn't have one, unfortunately I am not sure myself exactly what it does?

I am testing the voltage between the mixer valve and the tiles on the floor.

I don't think it is coming from another source, I think it is a draw from the neutral. I have also grounded both shower systems.

Thanks
Mick

This is going to take some time to troubleshoot. I would test from the drain to ground, and water to ground, to see if the source can be determined.

If you have "grounded both shower systems", how is this done?

Connecting all water and drain lines together and to the ground of the electric system, should bring all of this to equal or zero potential, and no flow of current should be measured between either system.

Is the water system a city water type with metal pipe coming in from underground distribution system?

Same for the drain?

Is electric service underground also?

The reason I ask is because I have seen underground electric lines short out or touch underground water or drain lines and energize them. Or the stray current is from another tenant nearby.

I do not believe this is a neutral problem, thou I have been wrong before.

Has the electric system neutral been grounded properly?

There could be a fault or short in your building touching either the water or draon, and if either is not grounded can have the potential on it.

These are the types of situations that can cause your sympton, and as you can see, there is not a simple answer.

Thanks for your reply, I have bonded an earth to both supply pipes to ground it.

The supply comes from the storage tanks on the roof and no one else uses them. I really can't think of any other source of power coming in and if there was I thought there would be 220v running through the water, that's why I thought it could be a little feed from the neutral.

My electrican said he can come over tomorrow anyway so if we get if solved I will let you know what the problem was.

Thanks again for your time
Mick

Yes, please let us know what you find.

One other thing to look for is a plastic pipe or some other insulating component in the piping system that may be allowing a section to be energized and not getting grounded.

This is definitely a weird one, and really is going to be a challenge to find, but I bet it will be something simple.

Thanks for your reply, I have bonded an earth to both supply pipes to ground it.

The supply comes from the storage tanks on the roof and no one else uses them. I really can't think of any other source of power coming in and if there was I thought there would be 220v running through the water, thats why I thought it could be a little feed from the neutral.

My electrican said he can come over tomorrow anyway so if we get if solved I will let you know what the problem was.

Thanks again for your time
Mickif you have copper and gal pipe a dielectric coupling should be in between them and there is no jumper in between, then it is not grounded