Hi All,
I have a very mystifying problem on a very simple circuit.
It is a new radial circuit for a garage power supply, it's wired in 2.5 T&E 16A MCB 30mA RCD. The cable goes directly from the dis board up the wall in trunking to the roof space where it is clipped to the joists before coming down the opposite wall under plastic capping which has been drylined over, feeds two double sockets and one single, then goes back up the wall into the loft before it comes down the adjacent wall in two drops for two double sockets and finally back up the wall into the centre of the ceiling for a garage door motor.
I did the first fix about 6 months ago and the second fix has just been done.
The live to earth IR is not brilliant at about 120 M Ohm but obviously OK, the problem is when I screw any of the sockets into the back boxes the IR goes down to 2 M Ohm. The boxes are just screwed to thermalite blocks and they are not earthed. I have tried different sockets but no difference. If I push the sockets into the boxes but don't screw them in it's OK.
I have carried out end to end tests and all OK, As far as I can I have inspected the cables and cannot see any damage.
It doesn't make sense to me; any thoughts.
Cheers
I have a very mystifying problem on a very simple circuit.
It is a new radial circuit for a garage power supply, it's wired in 2.5 T&E 16A MCB 30mA RCD. The cable goes directly from the dis board up the wall in trunking to the roof space where it is clipped to the joists before coming down the opposite wall under plastic capping which has been drylined over, feeds two double sockets and one single, then goes back up the wall into the loft before it comes down the adjacent wall in two drops for two double sockets and finally back up the wall into the centre of the ceiling for a garage door motor.
I did the first fix about 6 months ago and the second fix has just been done.
The live to earth IR is not brilliant at about 120 M Ohm but obviously OK, the problem is when I screw any of the sockets into the back boxes the IR goes down to 2 M Ohm. The boxes are just screwed to thermalite blocks and they are not earthed. I have tried different sockets but no difference. If I push the sockets into the boxes but don't screw them in it's OK.
I have carried out end to end tests and all OK, As far as I can I have inspected the cables and cannot see any damage.
It doesn't make sense to me; any thoughts.
Cheers