Question about earthing

[nanuuk]

I've recently had a combi installed and, due to the fact that the gas meter is a long, long way from the electricity meter they said it would be easier to put in an earth rod to connect the gas pipe to earth, rather than take 16mm cable all the way back to the electric meter. I didn't see them test the rod, but maybe they did while I wasn't looking.

Firstly question, was it necessary to earth the gas pipe between meter and boiler, when
1) The gas supply pipe is plastic
and
2) The water system uses exclusively plastic pipes (apart from the first 2 metres from the boiler which are all copper.

Second question, if my electricity supply is PME, and I add an earth rod, does it in any way change the parameters of the protection systems in the CU? I thought normally PME doesn't use any earth rods, I've not seen any diagrams showing that, so was just wondering... Perhaps it's a dumb question.

thanks,
NN.

 

[ricicle]

Who said it would be easier - were they electricians ?
That is not the correct way to equipotential bond the gas main. Extraneous conductive parts must be bonded to the main earthing terminal - that is the whole point of it, to tie in with the building's earth not the outside earth.

 

[nanuuk]

Blimey, good job I asked. I had a sneaking suspicion something might be iffy about this, but I don't really know the theory behind it.

I don't think it will be a hard job for me to disconnect the earth rod and take the cable round the outside of the house, then get an electrician to connect it to the CU. Should I do that with 16mm or 10mm?

thanks!
NN.

 

[ericmark]

Equipotential bonding. Electrical connection maintaining various exposed-conductive-parts and extraneous-conductive-parts at substantially the same potential.

The only way to get same potential is to connect them together.

 

[RF Lighting]

were they electricians ?

No!

I don't think it will be a hard job for me to disconnect the earth rod and take the cable round the outside of the house, then get an electrician to connect it to the CU. Should I do that with 16mm or 10mm?

How long will the run of cable from the gas meter to the consumer unit be?

 

[nanuuk]

How long will the run of cable from the gas meter to the consumer unit be?

About 15m

 

[RF Lighting]

10.0mm² will be fine for that

 

[JohnW2]

How long will the run of cable from the gas meter to the consumer unit be?

About 15m

10.0mm² will be fine for that

Although I suppose it could precipate a lot of debate about 'non-continuous' main bonding conductors, I guess another question which could be asked is how far apart are the water and gas pipes (or perhaps meters) where they enter the house.

Kind Regards, John.

 

[RF Lighting]

No debate to be had. No-continuous bonding is allowed, continuous bonds are better, and individual bonds are best.

 

[JohnW2]

No debate to be had. No-continuous bonding is allowed, continuous bonds are better, and individual bonds are best.

I agree totally with that - but just because there's no debate to be had from you, that doesn't meant that there's no debate to be had

... and, FWIW, I' not sure that I regard a continuous bond (to both services) as significantly inferior to individual bonds.

Kind Regards, John.

 

[RF Lighting]

No debate to be had. No-continuous bonding is allowed, continuous bonds are better, and individual bonds are best.

I agree totally with that - but just because there's no debate to be had from you, that doesn't meant that there's no debate to be had

Yes it does.

... and, FWIW, I' not sure that I regard a continuous bond (to both services) as significantly inferior to individual bonds.

You used the word significantly.

There's nothing wrong with a looped bond, but individual bonds are better.

I rewired my living room in flush steel conduit with LSF singles. There's nothing wrong with T&E, but singles in steel is better.

 

[EFLImpudence]

The gas supply pipe is plastic.

Are you sure?

 

[RF Lighting]

The gas pipe to my house is MDPE to the main isolator tap and then copper after the meter.

 

[JohnW2]

No debate to be had. No-continuous bonding is allowed, continuous bonds are better, and individual bonds are best.

I agree totally with that - but just because there's no debate to be had from you, that doesn't meant that there's no debate to be had

Yes it does.

Oh dear - have you forgotten that there are many around here who like challenges?

... and, FWIW, I' not sure that I regard a continuous bond (to both services) as significantly inferior to individual bonds.

You used the word significantly. There's nothing wrong with a looped bond, but individual bonds are better.

Yes, I understood what you were saying, but I think I could probably have omitted the word 'significant' from my comment. What I was implying was that I think I would struggle to think of any sense in which individual bonds are 'better' (even when the usual 'plumber' stories are invoked!). In what situation would you regard the individual bonds as better, or a looped (continuous) bond as 'worse'?

Kind Rgards, John.

 

[JohnW2]

The gas pipe to my house is MDPE to the main isolator tap and then copper after the meter.

I'm sure I've also seen that - but lots of people around here always say that it is 'not allowed'.

Kind Regards, John.