Hello
My shed is supplied by a 40 amp dedicated circuit, through around 25m of 6mm T&E and SWA, to a garage consumer unit. It's a TN-S supply and the earth is exported. The garage CU is a BG unit. It has a 40A RCD and two MCBs, 32A ring and 6A lights. Rather overkill but there you go!
I've lost all supply to the shed. I won't have a chance to get the multimeter out until the weekend, but I noticed this morning that when I pressed the RCD test button it didn't trip. My questions to help me troubleshoot are:
bsr
My shed is supplied by a 40 amp dedicated circuit, through around 25m of 6mm T&E and SWA, to a garage consumer unit. It's a TN-S supply and the earth is exported. The garage CU is a BG unit. It has a 40A RCD and two MCBs, 32A ring and 6A lights. Rather overkill but there you go!
I've lost all supply to the shed. I won't have a chance to get the multimeter out until the weekend, but I noticed this morning that when I pressed the RCD test button it didn't trip. My questions to help me troubleshoot are:
- Should the RCD trip on the test button if there is no supply? Or does that indicate a faulty RCD?
- How does one test if the RCD has failed open? Can I just test for continuity across the input and output for each pole or would the multimeter current trip it?
- Similarly for the MCB in the CU, would you test continuity across the MCB while it's still in the (de-energised CU)?
- If the RCD has failed, would you replace with another RCD or a DP switch? I have an 18th ed split load board, so the circuit is already 30mA RCD protected.
bsr