Shock!!!

[lutador]

Hi everyone this is my first post, i will thank you in advance to anyone that replies.

Recently had dormers fitted to the house and replaced heating system that was in the loft with a combi boiler to heat the full house, a corgi registered heating engineer did the work, but now and again i get quite a bad shock from the dishwasher or sink and if i have my hands on both at the same time...ouch, has he forgot to earth (i read some previous posts) the pipes and if so where should they be and attached and earthed to what? never got a shock before the work was done so i assume its something he did.

thanks

 

[resq]

Sounds like you need the problem investigated by an electrician or get the installer back.

 

[Qedelec]

There is no requirement to bond the sink, you would be wise to get it checked properly. Sounds like you have no RCD on the sockets.

 

[Shades]

All your copper pipe work and metal sinks should be cross bonded/earthed back to your Elec-fuse board. It is common in private domestic dwelling not to have this done. It does not hurt to have an electric check done on your home every few years, make sure that the Electrician can provide you with an electrical safety certificate before he starts.

If there is any problems he will identify them and provide a cost to rectify. You may save a few quid by not having it done but then it may save your life, and its a good thing to have if you come to sell you house.

P.s I am not an electrician I was a surveyor/contracts manager with extensive knowledge in the building industry, like everyone else my knowledge is limited.

 

[JohnD]

agree in principle, although the requirement to bond sinks was withdrawn many years ago.

If the incoming water and gas pipes are bonded, and you have a good earth connection through the electrical circuits to all your appliances, including the boiler and the dishwasher, this should not happen.

You would do better to get a recommended local electrician in, when calling, ask if he is a member of a self-certification scheme; which one; and what name he is registered under (if he is properly qualified he will not be offended at being asked).

Althogh it is possible the CH installer has made a mistake, there is probably a fault in your electrical circuits, as good earthing is supposed to prevent you getting a shock even if there is a faulty appliance in the house.

 

[lutador]

Thanks for the replys i will get a sparky in, better safe than sorry.

 

[securespark]

All your...metal sinks should be cross bonded/earthed back to your Elec-fuse board.

Should they?

Can you quote which regulation in either the 16th or 17th suggests this?

Regulation 413-7 in the 15th covered this, but that was current from 1981 - 1992.

This requirement was deleted from the 16th.

If you take a cable from your sink back to the fuseboard, that is even worse, as you are creating a direct parallel path...

 

[ricicle]

Sounds like you have no RCD on the sockets.

You could still receive a perceivable shock with a RCD fitted but it would hopefully not be of a harmful magnitude

 

[Qedelec]

Sounds like you have no RCD on the sockets.

You could still receive a perceivable shock with a RCD fitted but it would hopefully not be of a harmful magnitude

Blimey! Don't tell me you can 'feel' 30mA. you could be useful for fault finding

 

[dave12]

I have had a similar experience to this.

A while ago my wife kept telling me that she kept getting an electric shock off the sink! So after touching the sink myself, I felt nothing. So I obviously told her to behave herself (words to that effect). Anyway she continued to complain, so it ws out with the Fluke to see what was happening.

To cut along story short, I disvcovered that when the electric hob was on, the chasis, of the hob was live! The insides were ok (no burns or anything). But for some reason the live was shorted to earth. I traced the cable back and found that the cable was running accross a 8mm central heating pipe. The cable had obviously melted and caused the live to short onto the Earth. So I made the circuit safe and all was ok. Funnily enough I had not long installed a combi too (probably coincidence).

At the time I had the Old Fuse wire type CU, and it never blew! So I have now changed the CU to an up to date split loader.

Oh and yes I was made to apologies to the wife

 

[oharaf]

Hi guys, this sink bonding thing....

a lot of the fellas at college are talking about it at the minute, including the tutors and I have certainly been given the impression that it has come back.!!

But as John D has said there is no ref. made in 16th or 17th (I am still awaiting my copy on 17th!!!! )

Why would this be?

 

[thompsk]

Hi guys, this sink bonding thing....

a lot of the fellas at college are talking about it at the minute, including the tutors and I have certainly been given the impression that it has come back.!!

But as John D has said there is no ref. made in 16th or 17th (I am still awaiting my copy on 17th!!!! )

Why would this be?

I read it myself in the 17th edition the other day that there is no requirement for sinks, showers,radiators etc to be cross bonded providing that the earth on all mains services is present, connected and of the right size.

I was taught at college (15th ed) we were told to x bond everything and its something I have always done since, but being as the powers that be have declaired it a non necessity then dont do it if it dont need doin.

 

[333rocky333]

I read it myself in the 17th edition the other day that there is no requirement for showers, to be cross bonded providing that the earth on all mains services is present, connected and of the right size

As well as rcd protection to all bathroom circuits
If the shower was in the bathroom

At present it may be easier and cheaper to extend the supp bonding rather than altering the wiring etc and fitting RCD protection.

 

[plugwash]

The cable had obviously melted and caused the live to short onto the Earth.

If the earth was intact then that should have blown the fuse even if it was a rewirable.

Did you test the earth to make sure it was actually intact?

 

[Softus]

I very rarely see any bonding done correctly.

Yesterday I removed a heating system, and found one section of neatly bent copper pipe that was bonded to itself over a 6 foot run. And the earth cable wasn't connected to anything else.