Radiator earth bond

[AndyPRK]

someone was doing star jumps in their bathroom once

 

[securespark]

 

[ericmark]

As you say the idea of bonding is to ensure all metal at the same potential, the problem is if a standard lamp was knocked over by the dog in one room and the bulb smashed against the radiator in that room one would hope you would see the damage so no real problem you will turn off supply to lamp, but in another room the radiator may become live, but nothing in that room to alert you of the problem until you touch the radiator, so there was a move to earth anything which could transfer a fault from one room to another. However with plastic pipes the fault will not be transferred, and as with the bird on the electric wire, if a fault makes a whole room live, you are OK until you touch some thing earthed, so there is a balance, both earthing and not earthing can cause danger, so when the 17th Edition came out it was realised with RCD protection it is likely safer not to earth everything, and the rules for bonding in bathrooms now depends on if there is RCD protection or not.

However in general it is a case if uncertain then earth, OK technically bonding, but unless you know if all pipes are copper or plastic, and you have RCD protection on all circuits including the lights, then you don't really know if required or not, so safe thing is connect it.

 

[EFLImpudence]

Bonding is not for ensuring that an OPD trips if your standard lamp - in bathroom? - falls.

The rules on bonding have not changed for a long time.
Things like the OP's radiator were bonded because of misunderstanding the rules.

Even the introduction of RCDs has not actually changed the rules; they merely have a much lower Ia than fuses or MCBs.

 

[AndyPRK]

I thought that when the 17th came in, and effectivly lighting circuits were RCD protected, the bonding requirement was reduced

 

[EFLImpudence]

I thought that when the 17th came in, and effectivly lighting circuits were RCD protected, the bonding requirement was reduced

Not really.

It's just that with RCDs (plus the other two conditions) R ≤ 50/Ia is never NOT going to be the case.

Supplementary bonding "May be omitted" is not really the correct term to use. It is never going to be necessary.

 

[JohnW2]

Supplementary bonding "May be omitted" is not really the correct term to use. It is never going to be necessary.

Other than in an existing bathroom installation which is not RCD protected?

Kind Regards, John

 

[EFLImpudence]

I don't understand.

I was talking about with RCDs.

Not really.
It's just that with RCDs (plus the other two conditions) R ≤ 50/Ia is never NOT going to be the case.
Supplementary bonding "May be omitted" is not really the correct term to use. It is never going to be necessary.

 

[JohnW2]

I don't understand. I was talking about with RCDs.

Sorry - although it's not too obvious from your quote of yourself, the original was clearly two separate paragraphs, and I thought the second one was intended as a separate, general, comment, rather than actually being 'part of the first paragraph'.

Kind Regards, John

 

[aptsys]

A multimeter is only good for a very rough test of earth continuity. An Earth Loop Impedance tester is what is needed, to measure the low value of resistances involved with some current applied.

What else is required to determine whether bonding is required or not?


That makes no sense.

Low impedance measurements for these types of test are more accurate when a higher test current is involved. It's why loop impedance tests are typically performed at 10's of amps.

 

[EFLImpudence]

So if my multimeter, set to ohms, detects good continuity between the pipes, I can forget about bonding?

A multimeter is only good for a very rough test of earth continuity. An Earth Loop Impedance tester is what is needed, to measure the low value of resistances involved with some current applied.

Are people talking at crossed-purposes?

 

[aptsys]

Not sure. It's not the correct test to determine whether bonding is required anyway.

 

[EFLImpudence]

I'm getting lost.

Not sure.

OP was talking about measuring the continuity between his radiator pipes with a multimeter.

How can that be done with a Earth Loop Impedance tester?

It's not the correct test to determine whether bonding is required anyway.

What isn't?

What is?

 

[Harry Bloomfield]

I understand that bonding is to get two bits of metal, within arms reach, to the same voltage if there's a fault so I suppose someone sitting on a radiator using a hair dryer which

There will be, won't there? They are both connected to the radiator.

Not necessarily, there could be plastic pipes in the plumbing network.

 

[EFLImpudence]

What do you think is being discussed?

Not necessarily, there could be plastic pipes in the plumbing network.

They are both connected to the radiator.