High integrity earthing

[Zdb]

Only time I've done this has been using the two separate CPCs of a RFC using different terminals inside the D.B as per 543.7.1.204

I've been asked to test a load of high integrity radial circuits with two separate (different sized) CPCs.

My question is, in the box which asks for the CSA of the CPC, do you just write that of the radial and make a note of the other size in the comments or do you add the two CSAs together.

My initial thought was add them together but then I thought we dont write 3mm when installing a 2.5/1.5 RFC.

Any advice welcomed

 

[Pete999]

Only time I've done this has been using the two separate CPCs of a RFC using different terminals inside the D.B as per 543.7.1.204

I've been asked to test a load of high integrity radial circuits with two separate (different sized) CPCs.

My question is, in the box which asks for the CSA of the CPC, do you just write that of the radial and make a note of the other size in the comments or do you add the two CSAs together.

My initial thought was add them together but then I thought we dont write 3mm when installing a 2.5/1.5 RFC.

Any advice welcomed

That would be 4mm wouldn't it?

 

[Strima]

I would more than likely add them together and make a note on the cert reflecting the amount of cables on the circuit.

 

[Toneyz]

That would be 4mm wouldn't it?

I think Pete is correct there being a minimum of 4mm single earth when protected against mechanical damage.
If you are saying you have a 2.5/1.5 radial with a 2.5mm earth from the end of the radial to the distribution board I would put down 1.5 as the circuit CPC. What is the installation method?

 

[Deleted member 26818]

Only time I've done this has been using the two separate CPCs of a RFC using different terminals inside the D.B as per 543.7.1.204

I've been asked to test a load of high integrity radial circuits with two separate (different sized) CPCs.

My question is, in the box which asks for the CSA of the CPC, do you just write that of the radial and make a note of the other size in the comments or do you add the two CSAs together.

My initial thought was add them together but then I thought we dont write 3mm when installing a 2.5/1.5 RFC.

Any advice welcomed

Because that’s just one conductor.

 

[westward10]

That would be 4mm wouldn't it?

I think he is referring to the 1.5/1.5 of a ring final circuit. It depends on the schedule format you are using and whether you can insert all conductor csa. I like to include all as I hand write them so if you have a 2.5 T&E with a separate 4mm cpc I would put 1.5/4.0