Electric Shock In The Shower

[abneyelec]

Hi,

My brother complained that he had got a "mild" electric shock from the shower control and also from the heated towel rail. I went to his house today and tested the earth loop at the shower, the towel rail, the bath taps, literally every bit of exposed metal in the bathroom and it all tested fine, less than an ohm. I also checked to see if there was any voltage (difference in potential) between the metalwork and neutral and also to the earth on the sockets, again no problem here. I then cross bonded the pipework in the garage where all 5 pipes run next to each other.

He has rung tonight and said that he got a shock again, but only when the shower was "on" by the way it isn't an electric shower and there is no shower pump. I have to admit that I am a bit stuck with this one and would like some advice.
Cheers
Paul

 

[Plonker 3]

Never assume anything, always ask as it could be that simple.

 

[snowhead]

Why did it not trip the rcd it is on an rcd isn't it

29.999 ma really hurts, it's more than a mild shock.

I'm favouring static.

 

[Farmelectrics]

Yes your right

 

[Sparky Ninja]

I had similar to this last year on an insurance repair.

The bathroom guy had replaced the original plastic handrail for a new metal one and started receiving 'light shocks' when touching it while grouting (using the shower).

All earthing and bonding was satisfactory, light circuit had no cpc.

I took a long wander lead from the db, connected to earth, and just touched everything in the bathroom with the other end. Turned out the handrail was at 230V. The shocks were light as the guy wasn't in direct contact to earth himself.

In the end I disconnected the switch drop to the boys bedroom the other side of the wall and the fault had gone, it was crushed 10 or so years ago when it was moved and part of the wall has been live ever since.

 

[stidge]

I had similar thing mate, had fitted new cu , rcds etc , took me ages to find but they had overboarded downstairs kitchen and plasterer had screwed board , just nicked live which made above wall ( shower ) live at about 80 v when wet and shower on but didn't trip rcd( still don't know why) hope this helps !!!

 

[HandySparks]

I heard that you DO have to strip off to get proper readings. Don't you also have to insert a 17th Ed chicken feather into your anoose for the test to be reliable?

Made me smile. And yes, I did google "anoose", to see if was current lingo!

 

[the oracle]

I would suggest carrying out an insulation resistance test on the whole installation. A damaged cable anywhere could be contributing to this situation. I once had a situation where an outside soil stack pipe became 'live', and the builder was getting 'shocks' off of it. Turned out to be a lighting cable in the loft had been chewed by squirrels! Remember that electric shock of as little as 2-4mA can be perceived, 20mA is pretty painful and 50mA can kill, so your brother may well be receiving just a few milliamps. This would also explain why an RCD may not be operating. It also suggests that possibly, it is not the full voltage that is present. Have a look in the loft or wherever the water feed to the shower is, and maybe also the drain from the shower. Test any metalwork to the MET using an R2 lead (or an odd bit of singles) for voltage, and then continuity. If it is not coming off the metalwork, try the walls/floor etc. You may have a damaged cable within the building fabric that is 'livening up' the surfaces, especially when wet? Good luck, and stay safe!

 

[abneyelec]

Hi,

Thanks for all the replies.

The water and gas are bonded and the hot water pipework and the radiator pipework are cross bonded.
It is fed from a cylinder which is fed from a combi boiler.
I have tested earth continuity and earth loop at the shower tap, the towel rail and the bath taps. All fine.
I have tested potential difference between them and also between them and the neutral and the earth at a socket. I have also tested the walls and floors to see if there was any voltage there. nothing

I did all this without the shower running. I am going back today to do it all again with the shower running. I will post later if there are any changes.

 

[Farmelectrics]

interesting

 

[1shortcircuit]

Is the water bonded?

I still haven't managed to work out how you clamp to water??? I tried freezing it and almost had it but the ice thawed as quick as I could tighten the bloomin clamp :6:

 

[IzzyS]

Have I missed the part where you tested the IR?