Earth Bonding On A Worchester Combi Boiler

[peasie]

Hi all,sorry if this is in the wrong section.

Its just that over a year ago my father in law had a new combi boiler fitted in his utility room now the same fitters seviced it again a year later which was fine,but my father in law has just taken out AA boiler cover and they came to inspect/service it again and said there was no earth bonding attached.

He has tried contacting the original fitter but can't seem to get a hold of him just to see what he thinks as he doesn't mind at all having to pay to get the earth bonding sorted out.

I am just after some advice to where the bonding should go and what it entails.

Thanks In Advance Steve

 

[swbjackson]

Earth bonding is the remit of an electrician. I personally can't see why bonding would be necessary when all the pipes connect via a metal plate but it's a good idea to check with a sparky as they get very touchy about earth bonding.

 

[Hufty]

If you needed supplementary bonding, you would want one of these round each copper pipe, linked together. (You can usually get away without doing the safety vent pipe) You don't need to have an electrician do it.
http://www.screwfix.com/p/earth-clamp-ec16-pack-of-5/78314

Normally people link them with 4mm earth wire but if the pipes are close enough you can tighten the first one then thread it through the next one and so on, which looks neater.

I thought it was only ever if the boiler was in a bathroom. If the circuit is RCD protected you don't need supplementary bonding at all as of the wiring regs 17th edition. On the one hand doing it would keep your AA man happy, on the other hand sometimes you need to challenge this sort of thing. As swbjackson says it's probably a waste of time, but then a lot of the electrical regs are concerned with adding extra earth connections between things that are already electrically contiguous.

All the above assumes they were talking about supplementary bonding under the boiler and not the Main Earth Bond, which is an earth connection from the fuse board earth block to the gas pipe within 600mm of the meter outlet. Which you should have.

 

[Hufty]

Of course your original installer might have put one of these on
http://www.worcester-bosch.co.uk/in...nstar-28i-junior/accessories?accessory_id=214 in which case you're laughing

 

[FiremanT]

I thought it was only ever if the boiler was in a bathroom. If the circuit is RCD protected you don't need supplementary bonding at all as of the wiring regs 17th edition.

I thought so too. Maybe try posting on eletrical?

 

[gasman1987]

You don't need suplanenry bonding if you have a 17th edition consumar unit. If you have any other consumar unit then it is adviced. (best practice)

 

[peasie]

Thanks for the replies.

No the consumer unit is defiantly not 17th edition as it is an old one that still has fuse wire!

So what needs bonding there is 3 x 15mm pipes at the bottom and 2 x 22mm at the top i think i will double check tomorrow.

Thanks Steve

 

[TicklyT]

It may be that your electrics were installed to an earlier edition of the wiring regs that were in force BEFORE running earth wires everywhere and bonding every bit of metalwork in sight came into fashion.

Sometimes adding supplementary bonding to an electrical installation without FULLY understanding the existing electrical earthing and protection arrangements may render the electrical system unsafe. There are still some supplies around that are protected by voltage operated circuit breakers. That system worked well and was safe, but a misplaced earth bond of the sort that became the norm when residual current operated circuit breakers became more common can render voltage operated breakers completely ineffective.

 

[peasie]

If you needed supplementary bonding, you would want one of these round each copper pipe, linked together. (You can usually get away without doing the safety vent pipe) You don't need to have an electrician do it.
http://www.screwfix.com/p/earth-clamp-ec16-pack-of-5/78314

Normally people link them with 4mm earth wire but if the pipes are close enough you can tighten the first one then thread it through the next one and so on, which looks neater.

I thought it was only ever if the boiler was in a bathroom. If the circuit is RCD protected you don't need supplementary bonding at all as of the wiring regs 17th edition. On the one hand doing it would keep your AA man happy, on the other hand sometimes you need to challenge this sort of thing. As swbjackson says it's probably a waste of time, but then a lot of the electrical regs are concerned with adding extra earth connections between things that are already electrically contiguous.

All the above assumes they were talking about supplementary bonding under the boiler and not the Main Earth Bond, which is an earth connection from the fuse board earth block to the gas pipe within 600mm of the meter outlet. Which you should have.

As mentioned above the gas pipe is definitely earthed its right next to the meter.
But we are still confused about the other pipes needing earthed would it be ok to link all the other pipes to the gas pipe at the boiler?

And would this then make them all earthed?

The consumer unit is a old one that still use's wire not rcd breakers.

Thanks again Steve

 

[MJN]

As far as I am aware the only requirement for earthing is that of the boiler itself through its supply, and 'main bonding' which is the earthing of supply pipes (mains water, gas and oil) where they enter the building.

The practice of supplementary (cross) bonding where all pipes going in/out of the boiler are connected together seems to be just what many plumbers seem to just do as a matter of course. My understanding is that this is only required if the boiler is in a so-called 'special location' which is defined as a room containing a bath, shower, pool or sauna. Even then, under the 17th ed of the regs, if all circuits supplying the room are RCD protected then it is still not required.

I caveat this by admitting that this is just my understanding and so would welcome being corrected by an authoritative source. It might be worth you getting the AA to confirm exactly what their issue is because the term 'no earth bonding attached' is, at best, ambiguous. There could be the very real risk that he has simply got used to seeing example after example of the variety of ways a plumber can exercise his skill of ornate pattern creation with straps and coiled earth cable, and that when he stumbles across one without any 'curly wires' then he assumes there must be something wrong.

Mathew

 

[TonyW2]

I suggest this is moved to the electricians forum.
Supplementary bonding is a different matter to earth connections, and is obviously not a well understood concept. (Even apparently by some electricians ! ) so leave it to somebody who understands it AND can explain it in a comprehensible manner.
In any case, until it is established exactly what earth connection is not present, this is a futile conversation.

 

[vicvapour]

You don't need suplanenry bonding if you have a 17th edition consumar unit. If you have any other consumar unit then it is adviced. (best practice)

If main bonding is provided to the main water and gas pipes, if applicable, and earth fault loop impedance values are within acceptable limits (less than 1667 ohms), the supplementary bonding may be omitted in these areas.

 

[Kev F]

Waste of time bonding boilers now anyway as most of its plastic inside, apart from gas pipe I don't bother.

 

[vicvapour]

DUPLICATE POST

 

[dumbrill]

As mentioned above the gas pipe is definitely earthed its right next to the meter.
But we are still confused about the other pipes needing earthed would it be ok to link all the other pipes to the gas pipe at the boiler?

And would this then make them all earthed?

The consumer unit is a old one that still use's wire not rcd breakers.

Thanks again Steve

Supplementary bonding is not earthing. The objective is not to create a new earth path because that is what the earth in the mains cable is doing. Linking all the pipes to the gas pipe might make it a 'better' earth than the cable and I don't think that is a good idea.

The objective of supplementary bonding is to ensure that all exposed metal parts, ie. taps, etc are at the same voltage if there is a fault. Then you don't become a conductor if there is a fault and you touch both parts. As has been said it's not needed any more on modern installations.

Since your CU is so old you need to ask an electrician.