No it is not another bonding question,But similar

[the pict]

As a RCD will limit magnitude to 30mA, is that why supp bonding is omitted when fitted, or am I still hung over
Pict
Pict

 

[Knobhead]

A RCD doesn’t limit leakage current to 30mA. It’s the threshold it should trip at.

 

[the pict]

Is it not one and the same,
Pict

 

[malcolmsanford]

Yes an RCD will comply to 2 of the situations in Reg 701.415.2 the 3rd will be if you have main protective bonding of the installation as in reg 411.3.1.2

 

[the pict]

So if a sub board serves an area with no extraneous or exposed conductive parts and no incoming services that are conductive, then only the main earth conductor is required??

 

[malcolmsanford]

if there is no extraneous conductive parts or metal services what is there to bond?

If there is no exposed conductive parts, in essence you have a class II installation so you may not even need technically an earth conductor, but I have yet to see anywhere apart from very specialized installations, that do not have any exposed conductive parts.

Is this just a general thought thrown out or are you working somewhere like this

 

[Deleted member 26818]

As a RCD will limit magnitude to 30mA, is that why supp bonding is omitted when fitted, or am I still hung over
Pict
Pict

I think you may be confusing this with limiting the touch voltage to no more than 50V.

 

[the pict]

This is a small guest house, with a sub, fed from a sub, with no RCD protection, installed some 20 years back, SWA incomer from a 32A C type breaker feeding a DB for 1 room, 1 x 32A socket RFC, 1 x 6A lighting with 5 A sockets & 1x 16A Heater circuit, there are 5 boards like this, all rooms have been totally refurbed, all plumbing in in PVC with some copper interconnections, so there is no introduced potential, ZSDB is .19, and all served points in the bath/shower are at .02 to the main earth terminal at DB so the sup bonds are all good,but should the exposed copper pipe be bonded as this enters the bathroom from the service cupboard housing the DB.
Pict

 

[malcolmsanford]

Check any copper pipe exposed is in fact an extraneous conductive part simply by using your wander lead attached to MET of the installation and then an IR test on the pipe, it is is over 22KΩ then it's not one and no need to bond.

As there is no RCD protection I would definitely be testing every bit of metal pipe in that room, to make sure it is safe.

Not sure what you mean by served points in the bath/shower are at 0.2, if your saying that there are metal pipes having continuity back to the MET, you will need to bond them as in local supplementary bonding.

 

[the pict]

Sorry what I meant that the light,shaver socket, illuminated mirror, towel rail etc are all at or around .02 cont back to the earth bar,

 

[malcolmsanford]

All that proves, which is good, is that your CPC is continuous back to the MET.

 

[Chr!s]

As a RCD will limit magnitude to 30mA, is that why supp bonding is omitted when fitted, or am I still hung over
Pict
Pict

An RCD will not limit touch voltage or current.

 

[the pict]

semantics