New boiler wiring.

[SUNRAY]

I have had a boiler replaced in a rented flat.

There are 2 issues with the wiring:
1. Gas fitter says he cant make the final gas connexion until the earth bonding is completed.

PIR dated Dec 2015 states 10mm2 bonding and no other comment. I called the company who did the PIR and they kindly sent someone round to double check.

2. While he was there he noticed the new boiler is on a 13A plug and says it will fail the next PIR as water heaters must not be on plug/socket.

I have hardly had any involvement in this side of things since 17th came in but I recall this to be the case under 16th.

Paper work for the main supply shows 60 fuses in cut out.

Opinions please.

 

[Taylortwocities]

Both of these are common misunderstandings by many of our gas plumbing bretheren, bless them.

1. It depends on what he means by earth bonding. The only bonding needed is the main bonding (ie the 10mm² conductor between the consumer unit MET to the incoming gas and water main).
The PIR says it is present. Many gas operatives think that all of the pipes leading to the boiler need also to be connected together. Like this

This is NOT NECESSARY. Even if it were, if he looks up inside the bolier, all of the pipes are all bolted to a common steel plate.

2. The requirement for the electrical connections to a boiler says that it should be a double pole switch with a contact separation of 3mm or more. The switch on a double pole socket achieves that. Better, if you pull the plug out then the contact separation is probably a foot or more!
BS7671 includes a plug and socket as a valid means of isolation.

 

[EFLImpudence]

Assuming the 10mm is the Main Bonding from entry point of Water and Gas Supply to the Main Earthing Terminal near main fuse or in the CU, then -

1
Plumber is probably referring to what they call "cross bonding".
That is connecting together all the pipes beneath the boiler.
This is NOT required and does nothing but they will never accept it.

2
If the 13A plug (fitted with 3A fuse) supplies and therefore disconnects ALL the heating system I don't see a problem (not sure there is an actual regulation).
However, if it just supplies and disconnects the boiler with other parts of the system left live then it should be altered.

 

[SUNRAY]

Assuming the 10mm is the Main Bonding from entry point of Water and Gas Supply to the Main Earthing Terminal near main fuse or in the CU, then -

1
Plumber is probably referring to what they call "cross bonding".
That is connecting together all the pipes beneath the boiler.
This is NOT required and does nothing but they will never accept it.

2
If the 13A plug (fitted with 3A fuse) supplies and therefore disconnects ALL the heating system I don't see a problem (not sure there is an actual regulation).
However, if it just supplies and disconnects the boiler with other parts of the system left live then it should be altered.

Ah now then.... I had assumed he is refering to the mains gas and water pipes and cross bonding under kitchen sink and bath, it had not occured to me he may be thinking of something else.

There is only the combi boiler, it contains an internal wireless stat, no other wiring.

But it raises another question in my head, my heating at home has a FCU beside the time clock and wiring centre then a 4 core to the boiler via a 3pole isolation switch. Would that be wrong?

My recent work is in the controls industry where every bit of kit has a local isolator but I am talking about a completely different situation to domestic central heating.

 

[EFLImpudence]

Ah now then.... I had assumed he is refering to the mains gas and water pipes and cross bonding under kitchen sink and bath, it had not occured to me he may be thinking of something else.

Ok. (It's not called cross bonding - that's just a term plumbers use ??? - supplementary bonding is the correct name).

There is only the combi boiler, it contains an internal wireless stat, no other wiring.

A plug is fine, then.

But it raises another question in my head, my heating at home has a FCU beside the time clock and wiring centre then a 4 core to the boiler via a 3pole isolation switch. Would that be wrong?

Well, you have the FCU to isolate the whole system (assuming it does that) so that's alright.

If the 3 pole switch is next to the boiler then it may be useful for working on the boiler.
If it is remote from the boiler then it may cause confusion when isolating and be unnecessary.

 

[EFLImpudence]

That may seem to contradict when above I said
"However, if it just supplies and disconnects the boiler with other parts of the system left live then it should be altered"
What I was thinking there was that the plug may disconnect the boiler L,N & E but leave live connections from a thermostat for example.

The 3 pole switch presumably disconnects that as well.

 

[SUNRAY]

That may seem to contradict when above I said
"However, if it just supplies and disconnects the boiler with other parts of the system left live then it should be altered"
What I was thinking there was that the plug may disconnect the boiler L,N & E but leave live connections from a thermostat for example.

The 3 pole switch presumably disconnects that as well.

Gotya.
Yes the fcu feeds the whole system & is in the airing cupboard with time clock, pump, valves etc. Boiler is in another room. I fitted the 3 pole switch right beside the boiler to completely isolate it (L, N & SW L) as it's in a bit of an awkward position.

My question about the 13A plug at the flat was raised by the company who did the last PIR and reinforced by my own recollection that water heaters could only be on fixed wiring. I have dug out my 2002 copy of 16th and of course it only relates to electric heaters. BUT as I write this it occurs to me the boiler is isloated by plastic piping so I will sort that.

Thanks all for the help.

 

[Taylortwocities]

The ON SITE GUIDE says that immersion heaters should be connected through a switched flex outlet (ie not a plug/socket) but - like so much in the OSG - the regs are slightly different in their view.
The regs say that a double pole isolation facility must be provided and the water heater shall be permanently connected to the supply. So that removes the possibility of a plug/socket for an immersion.

The above regulation applies to "Electrode Water heaters and Boilers" but this section in the regs applies to things like large water heating vessels with heating electrodes, hot water tanks and not the devices produced by folk like Worcester, Vaillant, etc which are not actually boilers. I'll put on my Winston pedant hat here - if your Combi device boils then you have a serious problem!

This is probably where the plumbing fraternity have confused the requirement for "boilers" to have an FCU!

 

[ban-all-sheds]

If the 13A plug (fitted with 3A fuse) supplies and therefore disconnects ALL the heating system I don't see a problem (not sure there is an actual regulation).
However, if it just supplies and disconnects the boiler with other parts of the system left live then it should be altered.

If it the socket were replaced with an FCU, and whatever wiring that currently comes out of the plug is connected to the load terminals, then nothing will have changed.

This is NOT required and does nothing but they will never accept it.

A good way to get him to accept it would be to point out to him that he if he doesn't then he will not have finished the job, and that until he finishes he won't be getting paid.

 

[EFLImpudence]

Both true.

 

[OvertonPlumber]

Hmm surely the pir was conducted by an electrician. Not a gas fitter or plumber.
FYI lack of supplementary bonding is purely dealt with by a warning notice or in British gas's case a sticker.
There is no mandatory requirement for a pir. I suggest you change your letting agent. It's amazing you lot can agree on anything how many competence schemes are there for sparks. Roll on the 18th.!!

 

[EFLImpudence]

Hmm surely the pir was conducted by an electrician. Not a gas fitter or plumber.

I think you have misunderstood the OP.

FYI lack of supplementary bonding is purely dealt with by a warning notice or in British gas's case a sticker.

I have personally encountered gas engineers who will not commission a boiler without the bonding as in the picture.

There is no mandatory requirement for a pir.

That doesn't mean you can't have one.

I suggest you change your letting agent.

It's amazing you lot can agree on anything how many competence schemes are there for sparks. Roll on the 18th.!!

We seldom do.