Earth continuity and radiators

[IgnoramusMaximus]

I have recently extended a 1 rad GFCH (I couldn't afford a full system when I had the boiler installed!) up to another three radiators upstairs. By using pushfit below the floorboards I have no earth continuity to the rads and know I'll have to provide it, but I all honesty I can't see why?

The only way electricity is going to get to them is from the boiler and then via the water in the system. As that's already earthed at the boiler the rads can never become live unless I get very stupid with the electrics ...can they?

 

[JohnD]

you need supplementary bonding on metallic services in a bathroom

you do not need to bond radiators in other rooms.

this is an Electrical question

see //www.diynot.com/wiki/electrics:earthing_supply_types_and_bonding:supplementary_bonding

 

[D_Hailsham]

By using pushfit below the floorboards I have no earth continuity to the rads and know I'll have to provide it, but I all honesty I can't see why?

I don't think you are right about the need to provide earth continuity for the rads.

You will probably get a more reliable answer to this question if you ask it in the Electrical Forum.

 

[buster52]

the radiator pipework is cross bonded at the outlet supplys from the boiler and providing the radiator joint are metal to metal as designed then none of the radiators need cross bonding the only difference as someone has already said is in a bathroom more so if there is an electric shower involved

 

[IgnoramusMaximus]

the radiator pipework is cross bonded at the outlet supplys from the boiler and providing the radiator joint are metal to metal as designed then none of the radiators need cross bonding the only difference as someone has already said is in a bathroom more so if there is an electric shower involved

That's great, thanks everyone. I've put a towel rail rail in the bathroom but as I used copper above floorboard height that's easily bonded to the heating tails which come up underneath the bath. Everything else can do without. It seems that all my DIY books are wrong as they say continuity must be maintained for all rads.

Thanks, saved me a lot of work!

 

[buster52]

check to make sure your boiler has been earth bonded at the outlets

 

[JohnD]

Everything else can do without.

you haven't read that link I posted then? bathroom hot water pipe, cold water pipe, lighting circuit? Immersion heater maybe, electric shower maybe? Shaver socketr maybe?

 

[IgnoramusMaximus]

Everything else can do without.

you haven't read that link I posted then? bathroom hot water pipe, cold water pipe, lighting circuit? Immersion heater maybe, electric shower maybe? Shaver socketr maybe?

Yes I have thanks, which led me to extraneous (to normal regs) items in equipotential zones of special risk (ie, bathrooms). The only heating in the bathroom is the towel rail, everything else is H/C water supply and is copper throughout, so is already bonded. After it leaves the bathroom my CH dashes off under the floorboards via pushfit to the various bedrooms, so I assume the following applies:

"Items supplied only by plastic pipework are not extraneous and do not require bonding unless they are in contact with the building structure."

Otherwise I'd end up bonding the mirror, door-handle, window frame, razor blades... ??? Or have I misinterpreted the article?

And yes, the heating tails are bonded directly before they go upstairs, so it's just a 2m run of wire to the other end of the bath where the copper pipework for the towel rail goes . Then everything required should be the same potential.

 

[buster52]

if the heating goes into push fits joints the earth continuity is lost as plastic pipe and joints with neoprene o rings break the metal to metal so there for the towel rail is not earthed through the boiler, make sure its not anywhere near any possible contact to a source of power supply if in any doubt cross bond it to make sure

 

[D_Hailsham]

Read http://www.tlc-direct.co.uk/Book/5.4.3.htm

This refers to the 16th Edition of the Wiring Regulations, so it might be slightly out of date as the 17th Edition came into force on 1st July 2008.

 

[Congreave]

Bonding is not needed if you have used plastic fittings or pipe, even in a bathroom. The water in the pipes has too high a resistance for stray current to be a dangerous and bonding them could just make the radiators live in the event of an earth fault.

 

[JPC]

just a thought on cross bonding at the boiler...for yrs now i have been looping an earth wire pipe to pipe below the boiler...and i make it look very nice

However i fitted a boiler at an electricians the other week month and he asked me why ...as the boiler jig make the same connection...he got his meter out and showed me

So he has a point...do we still need to slap the earth wire on when using a single metal jig ?

 

[JohnD]

it is not an electrical regulation

however

while you are installing, removing or repairing a boiler, you may disconnect one or more pipes... at which time you will probably be handling it or touching it with metal tools, while leaning on the boiler or another pipe. Having them supplementary bonded should put everything at the same potential.

I don't do boilers so not my prob.

 

[Paul Barker]

I suspect that corgi inpsectors have been told to lay off over the electrical issues. At least that is my experience perhaps it is because i can show them better bits of paper than they have got or perhaps they realise it is a minefield which they aren't properly qualified to negotiate. Maybe a deal was done between Napit and Corgi? you stop poking your nose into electrical and we'll give up trying toget gas off you.

In the event didn't work since someone else with deeper pockets persuaded the powers that receive bungs to give corgi the chop.

My Napit inspector can tell some stories about the corgi guys they originally had to inspect on behalf of corgi.