Earthing problem

[cairwyn]

Ok , heres the problem , we had a combi boiler fitted over 10 years ago by a corgi registered plumber, 2 weeks ago my wife got a very slight shock when showering, i can turn the shower controls off and on and dont feel anything if i stand their clothed, yet when my wife showers and gets wet she gets this slight shock.
as i say this boiler has been in over 10 years with out a problem and now all of a sudden we get this ,
any help here appreciated guys , i understand enough about basic electrical work to run spurs and do lighting on a house in that through my work i'v watched and aquired this knowledge but now nothing realy about earthing

 

[Darkwood]

Firstly this could be very dangerous and advise getting a competent Electrician and not using the shower until your install gets a clean bill of health. When your wet your body resistance plummets and this is why your can't feel anything, do you have RCD protection although its not the bee's knee's everyone claims they are they still provide some extra protection.. the fault aybe on a totally unrelated circuit or even a voltage difference through your drainage routing through your wife to the earth of the shower.

 

[Badged01]

Now you are opening up a whole can of worms! There was a thread a couple of months(?) ago on showers and electric shocks and I dont think it was ever resolved!

 

[dan86]

Now you are opening up a whole can of worms! There was a thread a couple of months(?) ago on showers and electric shocks and I dont think it was ever resolved!

perhaps they got a belt and it killed em :dots:

 

[Badged01]

perhaps they got a belt and it killed em :dots:

I dont think there was any mention of hanging from the shower head!

 

[Marvo]

There's almost certainly more than one fault that needs repairing if the shower is giving shocks and with the high mortality rate of electric shocks whilst bathing or showering my advice is firstly stop using the shower immediately and isolate the shower circuit. Secondly find an experienced electrician to establish what faults there are and hopefully remedy them.

These kind of faults generally get worse over time so don't take any chances. If you don't have an electrician then maybe one of the forum regulars would be willing to help you out if you like.

 

[cairwyn]

why would it happen after all this time though , i dont understand that part , its been fine for 10 years
also its not an electric shower the only part with power is the the boiler , so i'm guessing it needs to be traced back as you say ,

 

[telectrix]

it would appear that you are getting a potential on the water pipes feeding the shower. this may only be a tingle at present but could escalate to a dangerous level. isolate shower and do not use until rectified by a competent electrician. if you look on the " electricians in your area " forum, you should find a few close to you.

 

[cairwyn]

sounds like good advice then , its beyond what i can rectify it seems i have a spark comeing to look at it shortly ,

 

[Marvo]

why would it happen after all this time though , i dont understand that part , its been fine for 10 years

Usually to get an electric shock there's at least two faults. Firstly the earthing or bonding of the item giving shocks is either missing or inadequate. Lack of earthing or bonding is a fault but in itself it won't result in shocks.

The other fault that's usually present is an insulation fault. As its name suggests it's where the insulation breaks down and allows the current carrying conductors or wiring to come into partial or full contact with the chassis of the appliance or item.

If the item is correctly earthed then, in the case of an insulation fault, no or almost no voltage can develop on the chassis and the flow of current to earth should cause the circuit to be disconnected by the protective devices (fuses or circuit breakers). Hence no shock.

The shock occurs when both faults happen simultaneously, the IR fault causes the chassis to come into partial or full contact with the supply and the lack of earthing allows the chassis voltage to rise sufficiently to cause current flow through anyone unfortunate enough to touch it. Both faults have a tendency to get worse over time, insulation steadily deteriorates and if the earth path is compromised by a corroded connection for example this also gets worse over time.

All this technical talk, whilst it answers your question is still a long winded way of saying it's not something you should be trusting yourself to fault-find and repair, please think long and hard about it before you do attempt it because people who receive a shock whilst bathing or showering are far more likely to get killed.

 

[cairwyn]

thanks , i was mostly interested in that if it was something simple that could easly be rectified then all well and good , it occured after i changed some batten holders for strip lights in the garage and accidently cut through a live cable on a switch , i thought the two might be connected in some way , i'm sure the spark will sort it when he gets here though , best to test it all me thinks

 

[Des 56]

and accidently cut through a live cable on a switch


cairwen

We have reputation in Wales for doing daft things on occasion

Unfortunately,electrics wise,you seem to be an accident waiting to happen


Aside from the main safety issue in this thread
If you are in future going to do any more electrical work,you are well advised to practice the absolute golden rule for working with electrics

It is the first and if not carried out correctly,the last action when doing electrical work
Look up the phrase "Safe isolation procedure"
It may save your life or even just your cable cutters,but it needs to be utilised