bonding in detached garage

Robo · Nov 30, 2012

TNCS supply.

Iv been asked to do an eicr.The garage is connect to house using 6mm 3c swa. There a plastic waterpipe which enters the garage. then goes to a sink and toilet which has some exposed copper sections on show. Do they need bonding? Both house and garage have rcd protection

jumpin jax · Dec 1, 2012

Is any of the pipework bringing in an earth potential?

telectrix · Dec 1, 2012

IR test between the melal pipework and your earth terminal. if rfeading is > 22k ohms, not extraneous so no need to bond.

Deleted member 9648 · Dec 1, 2012

The question is the service extraneous......unlikely if plastic. The exposed copper sections are also unlikely to be extraneous unless they are in contact with the ground or structural steel. If the garage is steel framed that may require main bonding. It is possible to test for ECP's. IR test between suspected ECP's and the MET. Less than 22Kohms is assumed ECP and needs bonding.
One point is that you state 6.0mm SWA.....this will not be suitable as a main bond to ECP's if the supply is TNCS....a minimum 10.0mm copper will be required back to the MET at the intake.

Edit...tel types quicker lol.

telectrix · Dec 1, 2012

not quicker. i just didn't put so much in .

Robo · Dec 1, 2012

So if i IR test between earth terminal in garage and ECP (sections of exposed copper pipe near sink) the reading needs to be above 22 kiloohms 22000 ohms and i dont need to bond. But if its below that i will need to put a 10mm earth in from the MET at the house.?

Will this method apply with regards to the copper bath to.

thanks

malcolmsanford · Dec 2, 2012

Robo said:
So if i IR test between earth terminal in garage and ECP (sections of exposed copper pipe near sink) the reading needs to be above 22 kiloohms 22000 ohms and i dont need to bond. But if its below that i will need to put a 10mm earth in from the MET at the house.?

Will this method apply with regards to the copper bath to.

thanks

That earth terminal in the garage is your Earth Marshaling Point (EMP) your MET is most likely at the origin of the installation in the house. You need to test there