1. Gather information
Ask the operators what happened and when: smoke, smell, noise, indicator lights, repeated trips. Check the load records.
2. Make it safe
- Insulated gloves, footwear and tools
- Isolate the incoming supply and the affected branches; discharge capacitor banks
- Lock off and tag every switch you have opened
3. Inspect
- Burn marks, deformation or corrosion on the cabinet; doors and locks
- Damaged, discoloured or loose wiring and terminals
- Signs of overheating on breakers, contactors, relays and fuses
4. Test
- Continuity of fuses, and the reason any fuse blew
- Breaker mechanism and insulation
- Contactor and relay coil resistance against the maker’s values; contact condition
- Insulation resistance phase to phase and phase to earth; low readings mean the fault must be found before re-energising
5. Repair
Replace damaged components with the same type and rating, re-make damaged wiring with sound insulated joints, tighten loose terminals and clean oxidised contacts. Check nearby circuits for knock-on damage.
6. Test again and re-energise
Repeat the insulation tests, energise without load and check indicators, meters, sound and smell, then add load in steps.
See our switchgear range and service page.