Emergency lighting circuit tripping / dead
A whole emergency lighting circuit is dead or its protective device trips — taking multiple life-safety fittings out at once, which must be restored quickly.
Safety first
Multiple life-safety fittings down is urgent. Don't just reset a tripping circuit — find the fault. Isolate and prove dead; licensed work.
Isolate, lock out / tag out, and prove dead before working unless a live test is specifically required, authorised, and carried out under proper supervision. Always follow local regulations, your site procedures, and the equipment manufacturer's documentation.
Full detail — causes, the why, and common mistakes.
Likely causes
Ranked from most to least likely.
- 1
Protective device tripped (fault on the circuit)
Most likelyA fault on one fitting or the wiring has tripped the circuit, killing all fittings on it.
- 2
A faulty fitting taking out the circuit
#2One failed fitting (or its charging circuit) faults the whole circuit.
- 3
Lost supply upstream
#3The circuit's supply is off/tripped at the board.
- 4
Wiring/connection fault
Least likelyA loose or damaged connection on the circuit.
Reports are saved on this device to reflect what you actually find.
Testing sequence
Work through one test at a time. Expected reading and what each result means.
Check the circuit's protective device and whether it has tripped.
Device on; not tripped.
Not tripped — trace the circuit for a supply/wiring fault.
Tripped — find what trips it (don't just reset).
View all expected readings at once
Fault-finding flowchart
The same logic as a decision tree.
- 1start
Emergency circuit dead/tripping
→ step 2 - 2decision
Has the protective device tripped?
Yes→ step 3No→ step 4 - 3decision
Does isolating a fitting/section let it reset and hold?
Yes→ step 5No→ step 6 - 4result
Not tripped — trace the circuit for supply/wiring fault.
- 5result
That fitting/section has the fault — rectify.
- 6result
Trips with all isolated — wiring fault; rectify.
Common mistakes apprentices make
- Repeatedly resetting a tripping emergency circuit.
- Not isolating fittings to localise the fault.
- Leaving the circuit dead/out of service.
- Overlooking a single faulty fitting's charging circuit.
When to stop & escalate
Emergency lighting faults are licensed and time-sensitive (life safety) — rectify promptly and re-test/record as required.
If you're past your competence, authorisation, or the safe limits of the job — stop and hand it on. There's no fault worth getting hurt over.
Related faults
Exit sign not illuminated
An illuminated exit sign is dark — it may have lost supply, failed its lamp/LED, or have a faulty driver. A life-safety fitting that must be kept working.
All lights in one area out (others fine)
Every light in one part of the house is dead while power points and other lighting still work — points at that lighting circuit's protective device or a shared fault.
A circuit breaker keeps tripping (domestic)
One circuit breaker keeps tripping — instantly on reset or after a load runs — and you need to tell an overload from a short or a faulty appliance.