Electrical Safety, First Aid and Fire Prevention
Electrical Safety, First Aid and Fire Prevention
This domain tests safe isolation, shock response and fire action for electrical and PV installations.
Core rules
- Isolate, lock out/tag out, prove dead with a tested voltage tester, and earth or discharge where required before work.
- Use PPE: insulated gloves, safety shoes, goggles, arc-rated clothing for live work.
- For electric shock: isolate supply first, call emergency help, check breathing, start CPR if trained, use AED. CPR compression rate 100–120/min, 30 compressions to 2 breaths for adults.
- Electrical fires: switch off supply; use CO2 or dry powder, never water or foam on live electrical equipment.
- PV modules produce voltage whenever exposed to light; DC conductors remain live even with the AC isolator off.
Worked example
A person contacts 230 V through a body resistance of about 1000 Ω. Current I = 230/1000 = 0.23 A = 230 mA. This is far above the threshold for ventricular fibrillation, so the priority is immediate isolation, not pulling the person by hand. A 30 mA RCCB would reduce disconnection time but does not make contact safe.
Traps that cost marks
Touching a shocked person before isolation; using water on an electrical fire; assuming the AC isolator de-energises the PV array; using a tester without proving it; rushing CPR without calling for help.