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EICR code for ring within a ring

Alan B

Doing an EICR at the moment and fairly sure I have found a ring within a ring, how would you code it?

Protective device 32A MCB and upstream 30mA RCD.

Shortest ring R1+R2 0.17

Longer ring R1+R2  0.54

r1 0.70

r2 0.87

rn 0.72

The short ring has most of the load as it covers the kitchen and fused spur to garage, the longer section is a couple of bedrooms and hallway

Above results to not include fused spur to garage R1+R2 1.10.

Normally I would put a 20A breaker in and code as a C3 but given the loads on the circuit not sure if in this sittuation I would end up with nuisance tripping. 

Appreciate your thoughts

Thanks

Parents
  • 0

    I think that I'd want to plot the test results on a plan of the house, and unless I have missed it, you haven't told us where the CU is in relation to the 2 "rings".

    With only 2 (T&E) cables in the CU, it appears that the larger ring is arising from the smaller one. So if for the sake of argument it has 6 points, the larger/outer ring comes off at point 3 and rejoins at point 4, or as ebee has pointed out, it could be at a JB between points 2 and 3; and 4 and 5, for example.

    Another way of looking at it is one long ring with a short circuit (or waist) between two points - they don't all have to join in one place.

    Good luck!

Reply
  • 0

    I think that I'd want to plot the test results on a plan of the house, and unless I have missed it, you haven't told us where the CU is in relation to the 2 "rings".

    With only 2 (T&E) cables in the CU, it appears that the larger ring is arising from the smaller one. So if for the sake of argument it has 6 points, the larger/outer ring comes off at point 3 and rejoins at point 4, or as ebee has pointed out, it could be at a JB between points 2 and 3; and 4 and 5, for example.

    Another way of looking at it is one long ring with a short circuit (or waist) between two points - they don't all have to join in one place.

    Good luck!

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