Level 4 of 33 · Electrical lab
A socket on an RCD
Level 4 of 33 in the Electrical lab: a free panel wiring exercise at Foundation level. Wire a socket outlet through a 30 mA RCD breaker, test the earth path and the insulation, time the RCD, then find an earth leak with the leakage injector.
Goal
A socket for the workshop is to be fed through a 30 mA RCD breaker (an RCBO.
What you do
- Lock out the board at the isolator Q1: switch OFF, apply your lock and your tag.
- Prove it dead with the meter or the voltage tester, live-dead-live: prove the instrument on the proving unit, check the board reads 0 V, prove it again.
- Wire the 8 conductors of the wiring schedule. Use the wire colour your standard gives each conductor.
- Test before you switch on, in this order: continuity of the protective conductors, insulation resistance, then polarity. The Installation tester in the toolkit does all three.
- Restore power: tick the checklist, remove your tag and lock, switch Q1 ON. Then the live tests: earth fault loop impedance and, on a socket, the RCD trip time.
- Try the circuit, then run the FAT.
- The injector R1 stands for a damaged appliance plugged in. With it at 0 mA the circuit is healthy. Set it to 30 mA.
Done when
The factory acceptance test is marked against the panel you built.
- 8 conductors in the wiring schedule
- 4 dead checks before you touch the panel
Skills
Wiring and testing at Foundation level.
Before you start
Level 3, Two-way switching: a stair light, comes first. Do it first if the ideas are new to you.
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