The Brief: To diagnose and fix a fault that was stopping the use of a circuit in the scullery.

Issue: Fault on Ring Main consistently tripping. In fact the RCBO (Residual Circuit Breaker with Overload) could only be turned on for a max if a few seconds and then it would trip, not long enough to do an RCD check.

Diagnosis: All ring tests carried out to ring main came back with normal and expected results for R1 (Line), R2(CPC) and Rn(Neutral) values for Continuity & Insulation Resistance too. It was found that the circuit that was at fault was not the faulty circuit. The circuit that was causing the fault was the cabling from the garage circuit.

The Garage circuit on the outside looked like it was all good. Customer told us that a suspicion was the previous electrician may have wired it incorrectly. On further investigation it was found that the the lighting circuit line conductor was borrowed from another circuit and joined together.

The sockets were joined from another ring main to share a ring main power supply to the garage line and its own ring main was connected to the consumer unit. All this amounted up to another completely independent circuit causing a consistent fault in that it was not the actual fault.

Findings: Separate circuits were joined to each other, possible Circuit Breaker fault on the other lines too, Type B and Type C RCBO’s mixed in the consumer unit. Dogs nest with other circuits that had cabling in the consumer unit that didn’t need to be there. Cabling for garage addition was not done to BS7671. All in all it was a very unfortunate situation for the customer to have to tell him that any changes or trying to fix to this system in the hope to clear the fault would mean that it would be easier to start again and replace the consumer unit and add a sub consumer unit to the garage to control these circuits independently from the main board. This way the fault will be certainly cleared and the upside was the system would now be in accordance with the latest BS7671 installation regulation requirements.

Customer was pleased with the diagnosis although unexpected was happy with the overall outcome.

Customer has continued to maintained a relationship with Figjam and has requested further work. A win for both parties.