Equipotential bonding

[David WE Roberts]

Read the Wiki, just need to double check.

Whole house re-plumb in plastic. So (apart from directly around the combi) there shouldn't be any metal in the hot and cold plumbing until you get to the taps. So in turn I assume that there is no bonding requirement for the H&C system as there seems no way that a faulty earth in an appliance (including bathroom lighting etc.) can cause current to flow through a person to earth via taps or water pipes.

Majority of the CH will be in plastic - the only copper is likely to be the incoming gas main up to the combi, a short run of 15mm pipe at entry/exit to the combi, and probably short tails on the radiators going below floor to join the plastic main piping for flow and return.

So earth at the CU should be bonded to the gas pipe as close to the entry into the property as possible (by the meter which is on the outside wall). Electrics around the combi should be bonded to the copper gas pipe. Oh, and the gas hob should be bonded to the gas pipe as well. Probably anything electrical in theoretical touching distance of a gas pipe (or the hob?) in the kitchen.

Is there anything else that should be bonded? With all plastic the traditional problem of routes to earth being created by metal gas and water pipes seem to have gone away.

Cheers

Dave R

[Owain]

No. The electrics are earthed by the circuit protective conductor to the main earth terminal, and the gas pipe is bonded to the main earth terminal. The boiler, if it requires earthing, will be earthed by the circuit protective conductor.

No.

No.

No, according to 17th Edition.

If your bathroom wiring is to 16th Edition (i.e. not all circuits are RCD) then you may need to equipotentially bond for the bathroom.

And the regulations are different for council houses. For council houses it's compulsory to earth everything (including the individual hot and cold taps). :-)

Owain

[David WE Roberts]

Umm..O.K. - for the combi and the hob I thought I was protecting against an earth fault in the wiring to the device (something as simple as the earth lead coming out of the socket), a break in the earth wiring somewhere in the circuit, or a faulty earth connection at the CU removing earth protection from the device, and then a subsequent fault rendering the device live but not tripping the breaker. So that when someone touched the device and the gas pipe, a new route to earth was created via the person, leading to a radical new hairstyle.

[ARW]

Would you mind if I copy and pasted your reply?

That is what I was going to post.

[tony sayer]

Umm ... why?..

[ARW]

I can only speak for the 16th edition and Doncaster council. They completely ignored the 16th edition rules and bonded everything. As I am no no longer allowed to work for them I have no idea what they do with the 17th edition rules.

Barnsley council seem to follow the 17th edition.

[John Rumm]

Yup. The fundamental question is "can the introduce a potential into the equipotential zone", so cosmetic stubs of metal pipe in an all plastic system can't.

The main EQ bonding should be in place - so gas main where it enters, and water main if it does so in metal.

Generally yes. Sometimes the connection is made on the consumers pipework in the meter box itself. On installs like mine where the meter feeds 14m of underground plastic pipe before it enters the building, it is done where it transitions to copper as it enters.

Is the combi in a bath or shower room? If not it sounds like there is not much requirement to bond the combi to anything.

Can't think why...

EQ bonding is not generally required in a kitchen since its not an area of special risk (you are less likely to be wet and naked one generally assumes ;-)

Not that jumps out at me...

Indeed.

[John Rumm]

Because council jobsworths with no actual understanding, get to make the "rules"...

[ARW]

Name one:-)

[Owain]

Feel free :-)

Great minds, etc.

Owain

[ARW]

No. The electrics are earthed by the circuit protective conductor to the main earth terminal, and the gas pipe is bonded to the main earth terminal. The boiler, if it requires earthing, will be earthed by the circuit protective conductor.

No.

No.

No, according to 17th Edition.

If your bathroom wiring is to 16th Edition (i.e. not all circuits are RCD) then you may need to equipotentially bond for the bathroom.

And the regulations are different for council houses. For council houses it's compulsory to earth everything (including the individual hot and cold taps). :-)

[Andrew Gabriel]

and, because they're always spending someone else's money (yours).

[David WE Roberts]

Ah - of course - I was applying the rules/logic to the whole house when it is only applicable to the bathroom. Hmmm.....rushes naked and cold and wet from the bathroom to beat the combi boiler back into life..... ...and we used to bathe the kids in the kitchen sink when they were very little...... Perhaps not entirely logical but rules is rules :-)

Thanks

Dave R

[Bob Eager]

The council leader's wife? Or someone else?

[John Rumm]

A jobsworth or a rule?

The latter would be easy - EQ bonding metal sinks and baths, or insisting that supplementary bonding must be visible in the room etc.

As for jobsworths, I try to keep away from them!

[John Rumm]

Although with hindsight - could you be thinking of a certain Mr. B?

;-)

[ARW]

:-):-):-)

[tony sayer]

Understooded prefeckly ....

[ARW]

What circuits are you planning on the rewire?

And it is nice to see someone using RCBOs and not just a dual RCD CU.

[tony sayer]

What's the typical price of RCBO's now of a decent make?..