Diagnostics
Electrical troubleshooting: breaker trips, flicker and dead outlets
Most electrical problems have ordinary causes. A few are warning signs that need immediate action. Knowing the difference helps you respond appropriately.
Overview
Routine problems versus warning signs
Routine problems are inconvenient but not usually urgent: an outlet stops working, a breaker trips when too many appliances run, a single bulb flickers. They often trace to a tripped GFCI, an overloaded circuit, a failed device or a loose connection.
Warning signs suggest heat or arcing and should be treated as potentially dangerous: burning smells, smoke, scorch marks, sparking, buzzing or crackling from outlets or switches, outlets or switch plates that are hot to the touch, or lights that dim dramatically when appliances start.
If you notice warning signs
Stop using the affected outlet, switch, appliance or circuit if you can do so safely — for example, by switching off its breaker — and contact a qualified electrician promptly. If there is smoke or fire, or you feel unsafe, leave the building and call 911. Do not open panels or remove covers to investigate.
Situations
Common reasons people look into this
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Breaker trips repeatedly
Overload, short circuit, ground fault or arc-fault detection.
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Lights flicker or dim
From bulb/dimmer issues to loose connections or service problems.
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Outlet or light stopped working
Tripped GFCI, failed device or loose wiring.
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GFCI will not reset
A fault downstream or a failed device.
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Partial power loss
Half the home dark can indicate a service or panel problem — call promptly.
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Shocks or tingles from appliances
Stop using the appliance and have it and the circuit checked.
Technical
Technical considerations
How electricians diagnose
Troubleshooting is systematic: understand the symptom and pattern, identify the affected circuit, test at the panel and devices, and inspect connections. Information you provide — when it happens, which outlets, what was running — shortens the process.
Common causes by symptom
- Breaker trips: too much load on one circuit; a damaged cord or appliance; a short or ground fault; AFCI detection of arcing (or nuisance trips from certain appliances).
- Flicker: loose bulbs, incompatible dimmers, loose connections in boxes or the panel, or — when widespread — a problem with the neutral or service connection.
- Dead outlets: tripped GFCI elsewhere on the circuit, a failed back-stabbed connection, or a tripped breaker.
What you can safely do
Reset a tripped breaker once; press reset on GFCI outlets in kitchens, bathrooms, garages and outdoors; unplug appliances on a tripping circuit. If a breaker trips again immediately, leave it off and call.
Assessment
What an electrician typically evaluates
Every property is different. A qualified electrician will usually look at the following before recommending any work.
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Symptom history
When, where and under what conditions the problem occurs.
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Panel and breakers
Tripped devices, heat damage, loose connections.
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Affected devices
Outlets, switches and fixtures on the circuit.
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Protection devices
GFCI and AFCI behavior.
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Wiring condition
Especially in older homes with mixed wiring.
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Service connection
For widespread flicker or partial outages, the utility side may be involved.
Talk through your situation
A short call can help you understand what an on-site assessment would involve.
Local context
San Francisco housing considerations
In older San Francisco homes, troubleshooting often uncovers mixed-era wiring, connections made without boxes, and circuits that serve unexpected rooms. In flats and apartments, symptoms in multiple units can indicate a building-level issue such as a loose neutral at the service or meter bank.
If several homes on your block lose power or see flicker at once, the issue may be on the utility side — contact the electric utility.
Permitting
Permits and inspections
Diagnosing a problem does not require a permit. Repairs may or may not, depending on scope: replacing a device like-for-like often does not, while replacing wiring, adding circuits or panel work generally does through San Francisco DBI.
Not legal advice. Permit requirements depend on the exact scope of work and the codes in force when the permit is issued. The provider performing the work is responsible for determining and obtaining the correct permits.
Frequently asked questions
Is it okay to keep resetting a breaker?
Resetting once is reasonable. If it trips again right away or keeps tripping, leave it off and have the circuit checked.
Why do my lights dim when the microwave runs?
Brief dimming can be normal on shared circuits, but noticeable or whole-home dimming can indicate overloaded circuits or connection problems. Have it evaluated, especially in older homes.
My outlet is warm — is that serious?
Outlets and switch plates should not feel hot. Stop using it, switch off the circuit if safe, and contact an electrician promptly.
Half my house lost power. What should I do?
This can indicate a problem with the service or main panel. Check whether neighbors are affected; contact the utility for outages, and an electrician if only your home is affected. If you smell burning or see smoke, call 911.
Official resources
Requirements change. Check current information directly with these official sources.
- San Francisco Department of Building Inspection (opens in a new tab) www.sf.gov Permits and inspections for electrical work in San Francisco.
- PG&E (opens in a new tab) www.pge.com The electric utility serving most San Francisco addresses; involved in service upgrades and meter work.
- CSLB license lookup (opens in a new tab) cslb.ca.gov Check a contractor's license number, classification and status before hiring.
Ready to talk to an electrical professional?
Call to speak with an electrical professional who can assess your property and explain your options.