Earthing an unearthed kitchen

[lip03]

I have just moved into a new flat and, whilst cleaning underneath the (ancient) kitchen units, have noticed the kitchen fittings (metal sink, gas hob, 15mm pipework) are not earthed.

Most of the pipework is plastic push-fit, but some is copper. The bits that enter the ground are plastic, with exception of the gas pipe.

I feel I should get the sink and hob earthed and have the bits to do so. My question is, is it safe / sufficient to use the only gas pipe as a link to earth?

 

[BoxBasher]

The reason for earthing usually to protect the user against electrical forces brought from outside the room, eg transferance of electrical current along pipework from faulty wiring under the floor.

Earthing makes a circuit between any live electical current and ground, this means that if you touch a live tap, it isn't you that completes the circuit causing current to flow through your body.

As you have plastic piping coming into the kitchen then this is not an issue as plastic is an insulator.

Your gas pipe is earthed and any existing electrical appliances such as toaster/kettle should be earthed anyway.

 

[sm1thson]

plastic pipes aside, i dont think bonding is done in kitchens now. the gas supply and water supply should be bonded just after the meter/ stopcock respectively (which may or maynot be be in the kitchen) -have a look there and tell us what you see.

 

[ample]

Supplementary bonding is not a requirement in kitchens, although the regulations always add unless there is a higher risk of electric shock. The gas main will have to be connected to a main equipotential bonding conductor, which will run back to your consumer unit. I assume this is your only gas main. A much misunderstood point is that the gas bonding has to be done at the point of entry to the building, and this doesnt always mean at the meter. Except of course if the pipework is innaccesible.

 

[lip03]

Ohh... Nope - the gas line comes out of the ground and splits into a T - one section goes to the hob, the other goes under the living room floor to the boiler. The section at the boiler is earthed to all the other pipes, which would be earthed (I've suddenly realised what is going on here...) back to... the RCD.

OK!

I might link the sink and metal bits of water pipework to the gas pipe seeing as I have the bits anyway. Just for the sake of using it up. Thanks for your help guys.

 

[sm1thson]

A much misunderstood point is that the gas bonding has to be done at the point of entry to the building, and this doesnt always mean at the meter.

hmm i was under the impression it was to be on the consumer's side of the gas meter, within 600mm and before any branches. but I'm not a spark and dont know the regs, anybody care to clarify (with something to back it up!)

 

[JohnD]

Yes it does. Can't be bothered to look it up unless someone bets me £10 or more.

 

[sm1thson]

Ohh... Nope - the gas line comes out of the ground and splits into a T - one section goes to the hob, the other goes under the living room floor to the boiler. The section at the boiler is earthed to all the other pipes, which would be earthed (I've suddenly realised what is going on here...) back to... the RCD.

yes it all links back to the CU (not RCD) but the Main eqipitential bonding (MEBs) should be a direct 10mmsq (or more) run reguardless of other equipotentol bonding elsewhere in the house -i know it all is connected one way or another but theres more to it than that, it should be bonded before the T straight to the main earth at the CU.

I might link the sink and metal bits of water pipework to the gas pipe seeing as I have the bits anyway. Just for the sake of using it up. Thanks for your help guys.

dont. this was removed from 14th edition because it can cause more problems than it solves.