Radiator earth bond

[DIYspanner]

I'm painting the radiator in a small en-suite with shower, toilet and sink.

I took the earth clip of the bottom lip of the rad to paint. The clip is well rusted so, is the earth bond required?

 

[flameport]

The pipes connected to the radiator might require bonding, the radiator does not and never did.

 

[EFLImpudence]

No.
However, the pipes might - and might already be.

Can you tell where the other end of the wire is?

 

[DIYspanner]

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

There's also a bond on the rad in the main bathroom. Why bond them if not required?

 

[crystal ball]

It was the style of the times, I remember being told to bond metal capping buried in plaster

 

[EFLImpudence]

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

It depends. It is complicated.

Can you tell where the other end of the wire is?

There's also a bond on the rad in the main bathroom. Why bond them if not required?

Because most people do not understand bonding.

 

[Harry Bloomfield]

So if my multimeter, set to ohms,

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.

 

[AndyPRK]

Are all circuits (or light circuits in bathroom) protected by a 30mA RCD ?

 

[DIYspanner]

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 has a fault, could make a circuit with the pipes via radiator?

I've tested the pipes and there's good continuity. The earth wire goes down into the floor. The electrics are the room light, shower light and shaver socket. The shower is a hot/cold mixer.

 

[EFLImpudence]

A multimeter is only good for a very rough test of earth continuity.

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

An Earth Loop Impedance tester is what is needed, to measure the low value of resistances involved with some current applied.

That makes no sense.

 

[DIYspanner]

Are all circuits (or light circuits in bathroom) protected by a 30mA RCD ?

The house was built in '92. The shower in the main bathroom and x2 socket circuits are via the 30mA RCD. The board is split and all other electrics switch off by normal switch.

 

[EFLImpudence]

I understand that bonding is to get two bits of metal, within arms reach, to the same voltage

That is correct.

if there's a fault so I suppose someone sitting on a radiator using a hair dryer which has a fault, could make a circuit with the pipes via radiator?

They could but that is not really to do with bonding. If someone touches a live wire then it would be better if no pipes were earthed - but some are.

I've tested the pipes and there's good continuity.

There will be, won't there? They are both connected to the radiator.
The question is - are they connected to the supply earth by some route?

The earth wire goes down into the floor.

Ok. Not known.

 

[DIYspanner]

So if there's continuity between the pipes because they're connected to the radiator, why the bond on the radiator?

I'll wager there are bonds betwenn c/h pipes, hot and cold pipes some where in the house.

 

[EFLImpudence]

So if there's continuity between the pipes because they're connected to the radiator, why the bond on the radiator?

Because some people don't know what they are doing.
As Flameport says; there has never been a need to bond radiators.

I'll wager there are bonds betwenn c/h pipes, hot and cold pipes some where in the house.

It very well could all be satisfactory. The CH pipes are joined by the radiator.

More important would be a continuity measurement between the CH pipes and the water pipes - if you can touch the radiator pipes and the taps at the same time.

 

[EFLImpudence]

I suppose I should have said -

More important would be a continuity measurement between the CH pipes and the water pipes and the light - if you can touch any two of the radiator, the taps or light at the same time - assuming all are metal.