Level 10 of 33 · Electrical lab
Find the faults
Level 10 of 33 in the Electrical lab: a free panel wiring exercise at Advanced level. A finished board with five faults hidden in it: a wrong neutral, a switch in the wrong conductor, a loose terminal, a wrong overload setting and a broken hold-in. Find them with dead tests first, fix them and test again.
Goal
This board was wired by someone else and handed over as finished.
What you do
- Lock out the board at Q1, prove it dead, live-dead-live.
- Dead tests first: protective conductor continuity, insulation resistance, polarity (the Installation tester), then a visual check of every terminal against the schedule, and the torque screwdriver on every terminal.
- Fix what you find: remove or add the conductor, tighten the terminal, set the dial. One conductor per terminal.
- Restore power, run the live tests, try the circuits, and run the FAT.
- Hints: the lamp circuit has two faults; the motor control circuit has two; and one setting is wrong.
Done when
The factory acceptance test is marked against the panel you built.
- 25 conductors in the wiring schedule
- 5 dead checks before you touch the panel
Skills
Fault-finding at Advanced level.
Before you start
Level 9, Timers and relays, comes first. Do it first if the ideas are new to you.
Free, in your browser, nothing to install. Your work is saved on this device. Updated 1 Nov 2026.