What are the actual legal requirements for supplementary bonding under gas boilers?

[casaco]

Does anyone know what is legally required regarding electrical bonding to pipework under the boiler. There was a guy caught illegally fitting a gas boiler in this months PHARM magazine, one of the things HSE did him for was a lack of bonding, didn't say where it was missing from, I am assuming that the meter was bonded, but even if it wasn't it is up to the customer to organize that I think. Some sparkies say it is needed, others say you don't. I will call gas safe tomorrow for clarification but I just wondered if anyone had the answer already.

 

[SimonJohns]

It depends on the wiring system.

16th. You have to cross bond under boiler. And mains.

17th. Only required on incoming mains.

 

[GQuigley67]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

if its wired to 17th edition regs i was told that as long as water main/gas meter are bonded you dont need to cross bond, but the same sparky has just cross bonded a boiler for me when he rewired the house the week before, so i'm confused now.

 

[casaco]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

Hi Simon, you have lost me there with the wiring system, not sure how the wiring system can affect the bonding requirements.

 

[GQuigley67]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

must have something to do with RCDs on new systems reducing the risk of earth problems as it would just trip if there was an earth fault

 

[SimonJohns]

There are different wiring regualtions. And depending on what the house has been wired to will depend on the requirements

The 17th edition. The newest and what is the standard now. Requires only bonding on gas pipe where it enters building. And same for water

On 16th edition. You have to cross bond every thing. The boiler. Pipes in bathroom. Services on point of entry.

Unlike gas. You need to find out what the house is wired to and conform to that.

If in doubt. Bond it all

 

[casaco]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

Hi, thanks for the quick reply, they have replaced all our water mains with plastic now so bonding the incoming mains doesn't really do much now unless you have the pme installed.

 

[GQuigley67]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

you can still bond plastic pipe as water is conductable

 

[SimonJohns]

I didn't know. But if you install a shower. The copper pipes should be broken with one plastic fitting on services to prevent any stray electric entering shower area

 

[casaco]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

Yes, I read somewhere that rcd's are required to avoid bonding, but I will ask gas safe and see if they have a technical bulletin out on the subject. Thanks again to all of you.

 

[GQuigley67]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

really Simon? thats news to me, never seen it mentioned in any MIs

 

[SimonJohns]

Also. I didn't know. That a shower floor if tiled should have a copper cable grid under tiles as an earth

Perhaps we should get a visit from the electrical forum. Maybe a trusted

 

[GQuigley67]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

never came across it, done an electric shower yday with sparky and he didnt mention it either

 

[mountainman]

I believe that a 30mA RCD is sufficient nowadays.

 

[GQuigley67]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

what for the earth ?

 

[badabing04]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

whats the score with bonding the blow-off? does it actually need bonding?

 

[Bernie2]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

Basically if RCD's are fitted they sometimes ask for bonding as well. Its on the basis that RCD's have moving parts that can stick and if they do you want an alternative Earth path ready. Lets be honest who presses the RCD test button at the required test times?

I have never quite heard the finished argument about bonding plastic incoming mains. I know water can carry electrical current of course, but wouldn't an earth clip that was on the outside of the pipe be insulated from the water by the pipe walls? Suppose you could clip on the copper pipe coming out of the plastic main if it has copper of course and it is not all plastic.

The regs normally say all exposed metals to be bonded

The main earth point can be in a few different places depending on the system of course. Usually a local earth rod is provided if the utility suppliers main cable does not have an earth point on its outer casing.

As to bonding underneath a shower tray? Not sure about that one. If you where in the shower it may make you an earth path for sure. The idea of bonding is to provide an earth path with less resistance than you.

 

[lambchop]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

you can still bond plastic pipe as water is conductable

Am I mtp, the water is inside the pipe the earth clamp is attached to plastic pipe so the earth clamp doesnt come into contact with the water unless youve got a leak?. Im noy taking the mick looking for an explanation

 

[AWheating]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

water is not very conductive really.

except in films 🙂

 

[AWheating]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

Also. I didn't know. That a shower floor if tiled should have a copper cable grid under tiles as an earth

Perhaps we should get a visit from the electrical forum. Maybe a trusted

dont really understand the point for this? why put something in that may increase the chance that the path of less resistance to earth is through the user into the floor? bonding the shower supply pipework would make more sense imo.

 

[AWheating]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

Am I mtp, the water is inside the pipe the earth clamp is attached to plastic pipe so the earth clamp doesnt come into contact with the water unless youve got a leak?. Im noy taking the mick looking for an explanation

the main bondings are required on the first bit of metal pipework after the stop tap, not on the plastic incomming main. the main and its water will not carry a current unless its protector pipe and theres a fault.

 

[quality]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

you can still bond plastic pipe as water is conductable

But plastic is not!

 

[kay-jay]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

hmmm the idea of breaking a copper supply to a shower with a plastic fitting, surely this would stop the current passing along the pipework in event of a fault, but would the current not transfer from the copper to the water and in turn pass through the plastic fitting via the water????

all a bit confusing

 

[wheeto]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

you can still bond plastic pipe as water is conductable

You might want to re-word that ... at first glance it seemed you were suggesting fitting earth clamps to plastic pipes!

 

[AWheating]

Re: What are the actual legal requirements for supplementary bonding under gas boiler

hmmm the idea of breaking a copper supply to a shower with a plastic fitting, surely this would stop the current passing along the pipework in event of a fault, but would the current not transfer from the copper to the water and in turn pass through the plastic fitting via the water????

all a bit confusing

water is not very conductive. it may tickle alittle if your unlucky.