Quick answer
Use a breaker tester to check if a circuit breaker is tripped or faulty. Turn off power, plug in the tester, and follow the indicator lights. Replace the breaker if it's faulty.
Confirm the symptom
- Circuit breaker won't reset
- Lights or outlets not working in a room
- Breaker trips repeatedly
- Breaker tester shows no power
Tools and prep
- Breaker tester
- Screwdriver (if panel cover is secured)
- Safety gloves and goggles
- Turn off main power before starting
- Ensure the panel is dry and clean
Step-by-step troubleshooting
- Turn Off Main PowerDo: Switch off the main circuit breaker to cut power to the panel.Observe: Lights in the room should go off, confirming power is off.Means: You're working safely with no live current.Next: Open the panel cover
- Open the Panel CoverDo: Use a screwdriver to remove the panel cover if necessary.Observe: Access to individual breakers is now visible.Means: You can inspect and test breakers directly.Next: Test each breaker
- Test Each BreakerDo: Plug the breaker tester into an outlet connected to the circuit you're testing.Observe: The tester's lights will indicate if the circuit is live or faulty.Means: A non-working outlet suggests a tripped or faulty breaker.Next: Check the breaker status
- Check the Breaker StatusDo: Visually inspect the breaker to see if it's in the 'on' position.Observe: A tripped breaker will be in the 'off' position or between on/off.Means: A tripped breaker needs to be reset.Next: Reset or replace the breaker
- Reset or Replace the BreakerDo: If tripped, turn the breaker fully to 'off', then back to 'on'.Observe: The breaker should stay in the 'on' position.Means: Reset successful if the breaker holds and power returns.Next: Test the outlet again
- Test the Outlet AgainDo: Use the breaker tester to check the outlet again.Observe: The tester should show normal power if the breaker is working.Means: The circuit is now functioning correctly.Next: Restore main power
Common causes
| Cause | Likelihood | Difficulty | Part often needed |
|---|---|---|---|
| Tripped Breaker Overload or short circuit in the circuit. | Common | Easy | None |
| Faulty Breaker Internal component failure or age. | Sometimes | Medium | Replacement breaker |
| Loose Wiring Poor connection at the breaker or outlet. | Sometimes | Medium | Wire connectors or electrician service |
| Short Circuit Wires touching or damaged insulation. | Sometimes | Hard | Electrician service |
| Ground Fault Current leaking to ground, often in wet areas. | Rare | Hard | GFCI breaker or electrician service |
| Overloaded Circuit Too many devices drawing power. | Common | Easy | None or additional circuits |
Parts matching
Common parts needed when using a breaker tester include:
- Breaker tester (basic or advanced model)
- Replacement circuit breakers (same amperage and type)
- Wire connectors (for loose wiring fixes)
- Screwdrivers (for panel access)
Always match the replacement breaker's amperage and type to the existing one for safety.
When to call a professional
- Breaker won't reset after multiple attempts
- Frequent tripping despite no overload
- Smell of burning or visible damage in the panel
- Tester shows inconsistent results
- Uncertain about breaker type or wiring
FAQ
Can I test a breaker without turning off the main power?
No, always turn off the main power before testing to avoid electrical shock.
What does a breaker tester actually check?
A breaker tester checks if a circuit is receiving power, detects wiring issues, and identifies if a breaker is tripped or faulty.
How do I know if a breaker is faulty?
If the breaker won't reset, trips immediately after resetting, or the tester shows no power despite being in the 'on' position, the breaker is likely faulty.
Can I replace a circuit breaker myself?
Yes, if you're experienced and follow safety steps. Otherwise, hire a licensed electrician.