Absolute Nightmare fault.

[GBDamo]

Reported fault was RCD tripping.

Another spark had been out and reported a Neutral fault on a ring circuit. As poewr could not be left off he removed the RCD (single RCD 7 way CU) and replaced it with a mains switch.

When I arrived there were two "ring" circuits in the CU one on a B32 and one on a B10.

Niether were rings however all IRs were in the high 100sMOhms at 500V, including to MET. So no fault evident.

Found the legs of one ring which had been mixed up in the CU and reinstated to an RCBO, could only find one accessory on the ring which had a spur to an outside socket, all tested ok and RCBO holds.

The two remaining cables had no ring continuity at all, found one accessory on one cable and this only had one feed in, again this tested ok and was reinstated to am RCBO and held.

At this point all expected power was back on with one ciruit still disconnected from the board.

This cable tested fine for IR but no accessory could be found to peform any other testing so was left disconnected.

Fully expecting to be back to rewire the faulty circuit but will at least kkow which one is faulty.

I would be interested to know how others would have approached this one.

 

[telectrix]

from what you say, you done it logically.' and, more importantly, made it safe by the use of rCBOs.

 

[GBDamo]

from what you say, you done it logically.' and, more importantly, made it safe by the use of rCBOs.

Cheers Tel, its one of those where you leave thinking Ive been here most the day, fitted a new board with RCBOs yet the customer has still, in all likelihood, got the fault.

As you say it is safe now being on RCBOs.

If/when it trips again we'll at least know which circuit its on.