Bathroom bonding!!

[liddley]

Hi guys,
Just wondered what size cpc to use when bonding all the seperate circuits together in a bathroom?
Is 4mm green and yellow suffuciant or is it 6mm. Not sure where to find it in the regs. Any one got any advice?:confused5:

 

[alanl]

CPC?
Separate circuits?

Do you mean supplementary bonding, connecting any metal extraneous parts to an earth terminal?
544.2. Minimum size of 4mm if not mechanincally protected.

 

[Dunc]

CPC?
Separate circuits?

Do you mean supplementary bonding, connecting any metal extraneous parts to an earth terminal?
544.2. Minimum size of 4mm if not mechanincally protected.

However it's not required if all circuits within the bathroom have 30mA RCD protection and the metal pipework is continuous with all main equipotential bonding in place. There is a test you can do from the MET to the pipework to confirm this but the reading it's supposed to be under defeats me at this moment in time.

 

[liddley]

yes when connecting the lighting , heating ,shower circuit and pipes ect.. together in special locations?
So 4mm is fine.

 

[alanl]

I think you have got it all wrong. You do not connect all of those circuits together. You connect extraneous metal to an earth terminal, or, in most places, the cold feed pipe, which is, or should be connected via a 10mm cabke direct to the CU/fusebox.
As Dunc says above, if you have a fully RCD protected board, then it is unlikely that you will need supplementary bonding anyway.

 

[MarkieSparkie]

The size of supplementary bonding conductors required is related to the size of the CPCs of the bathroom final circuits. See OSG Table 4.3 for details.
The general advice given in previous threads is fine, providing you don't have a non-standard installation.

 

[holte end74]

If you have got a fully protected rcd fuse board in a TT system then is supplementary bonding requiered?

 

[Deleted member 9648]

It is a commonn misunderstanding that 30ma RCD protection to all circuits within a bathroom means supplementary bonding is not required.
If supplementary bonding is to be ommited the following 3 conditions must be fullfilled.
1. All circuits within the location must be 30ma RCD protected
2. All extraneous conductive parts within the location must be effectively connected to the protective equipotential bonding......(a continuity test between simultanously exposed conductive parts and extraneous conductive parts within the location should read <1667 ohms)
3. All circuits within the location meet required disconnection times.
701.415.2
415.2.2

 

[holte end74]

thanks for the reply, so in a fully protected rcd board you only need to worry about condition 2 , how would you get the readings in pratice?

 

[ackbarthestar]

thanks for the reply, so in a fully protected rcd board you only need to worry about condition 2 , how would you get the readings in pratice?

Low resistance Ohmmeter to check continuity. You are looking for a value that is lower than 50V/Ia of the largest circuit load being supplied or in the case of RCD protected circuits 50/IAN.

If the values are higher than the above then:

Insulation Resistance Tester to check for Isolation

A value not less than 22k Ohms. That's 23k Ohms less the typical body resistance of 1K Ohms

Otherwise you will need to supplementary bond.