No power to the whole house
The entire home has no power — nothing works. Could be a supply outage, the main switch/main safety switch, or a main fault, and the first job is to tell which.
Safety first
Treat the switchboard and supply as live. Don't open sealed/supply-authority equipment (meter, service fuse). If a main device keeps tripping, a serious fault may be present.
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
Supply authority outage
Most likelyA network/street outage affects the area — check whether neighbours are also out.
- 2
Main switch / main safety switch off or tripped
#2The main switch or a main safety switch has been turned off or tripped.
- 3
A fault tripping the main protection
#3A significant fault on a circuit can trip the main device.
- 4
Service fuse / supply-side fault
Least likelyA blown service fuse or supply-side fault (supply authority territory).
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 whether neighbours/the street are also without power (or use the supply authority outage info).
Clarity on whether it's a wider outage.
Wider outage — it's a supply issue; wait/report to the authority.
Only this property — check the switchboard mains.
View all expected readings at once
Fault-finding flowchart
The same logic as a decision tree.
- 1start
No power whole house
→ step 2 - 2decision
Are neighbours / the street also without power?
Yes→ step 3No→ step 4 - 3result
Wider outage — supply issue; wait/report to the authority.
- 4decision
Are the main switch / main safety switch on (not tripped)?
Yes→ step 5No→ step 6 - 5result
Mains on but no power — suspect a supply-side fault (authority).
- 6decision
With sub-circuits off, will the main hold?
Yes→ step 7No→ step 8 - 7result
The sub-circuit that drops the mains has the fault — rectify it.
- 8result
Mains won't hold with all off — mains/supply fault (escalate).
Common mistakes apprentices make
- Opening the meter or service fuse (supply-authority equipment).
- Not checking whether it's a wider street outage first.
- Repeatedly resetting a main device that's detecting a real fault.
- Assuming a property fault during an area outage.
When to stop & escalate
Supply-side faults (service fuse, supply outage, meter) are for the supply authority. Faults tripping the main protection are licensed electrical work. Don't tamper with sealed/supply equipment.
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
Safety switch (RCD) keeps tripping at the switchboard
The safety switch trips repeatedly — instantly on reset, randomly, or when certain appliances run. It's detecting earth leakage somewhere; the job is to find where.
Lost or high-resistance neutral
Strange symptoms across a circuit or installation — voltages going high and low on different loads, flickering, equipment damage — pointing to a lost or high-resistance neutral.
No supply at a socket-outlet or point
A socket-outlet or point is dead — nothing plugged in works — while other points may be fine. A bread-and-butter 'trace it back' fault.