Main breaker tripped — what now.
Main breaker trips signal panel-level issues. One-time reset is reasonable; repeat trips call for emergency response.
By Steven Lockhart · Reviewed by Alex Towery, C-10 #989290
Updated 2026-06-16
Main breaker tripped: try one reset (firm OFF then ON). If holds: monitor; schedule diagnostic this week to identify cause. If trips again immediately: stop, leave OFF, call emergency electrician. If trips again after running for minutes/hours: significant overload at service level, diagnostic this week. Whole-house outage with main breaker tripped is internal issue (not PG&E) — covered earlier in power-out-but-neighbors-have-power cluster as well.
01What causes main breaker trips.
Three main causes: (1) Major fault somewhere in the house — short circuit or severe ground fault drawing massive current. Main breaker trips because the branch breaker (which should have tripped first for the specific circuit fault) couldn't handle the current, or the branch breaker has failed. (2) Service-level overload — total simultaneous load on the home exceeds main breaker rating. Happens occasionally in homes with old 100A service running modern load (multiple HVAC, EV charger, induction cooking, water heater all running). (3) Main breaker mechanical failure — older or degraded main breaker becomes sensitive and trips when it shouldn't.
Diagnosis depends on whether the trip was instant (suggests fault scenario) or after sustained load (suggests overload). Recent activity matters: was something major running when it tripped (AC, EV charging, electric water heater cycling)? Was a new appliance recently added? Was there any recent electrical work or weather event? All of these inform the diagnostic.
02Response by scenario.
Trip during heavy load
Service-level overload most likely. Reset main, then immediately reduce load (turn off AC, stop EV charging, etc.). Monitor whether reset holds with reduced load. Diagnostic visit to assess: total connected load vs main breaker rating, whether service upgrade (100A → 200A) is warranted.
Trip with no apparent cause
Could be branch fault that escalated to main, or main breaker mechanical failure. Diagnostic visit needed. Reset once to test; don't keep resetting if trips again — call electrician.
Trip with smoke, smell, or visible damage
Emergency. Don't reset. Call emergency electrician and consider 911 if any visible fire risk. Main breaker may need replacement; panel may need replacement; service entrance may need work.
03Cost and timeline.
Diagnostic visit: $250-$450 for emergency or same-day visit, typically 1-2 hours on-site. Identifies cause — branch fault that needs separate repair, main breaker replacement need, or service capacity issue. Main breaker replacement (if mechanical failure): $400-$1,200 depending on panel brand and main breaker type. Includes PG&E coordination if main breaker replacement requires meter shutdown.
Service upgrade scope (if 100A → 200A or similar): $3,500-$6,500 typical Marin install. Includes new main breaker, new service entrance components (often), PG&E coordination, permit and inspection. Timeline 2-4 weeks total project. Often combined with panel replacement if existing panel is also dated or undersized.
Common questions.
Is one reset attempt safe?
Yes for typical main breaker trip. One firm reset (OFF then ON) is reasonable diagnostic — does it hold or trip again? Single reset doesn't typically cause damage even if there's a fault. Repeated resets when there's a real fault: not safe — can damage breaker and worsen the fault.
What if I have a 100A panel?
100A panels are common in older Marin homes. Original loads (1970s-80s homes built with 100A) usually fit. Modern load growth (EV, AC, induction, electric water heater) often exceeds 100A capacity for sustained operation. If your 100A main is tripping with normal modern usage: service upgrade to 200A is the typical solution. Same project also typically upgrades the panel itself.
Will my insurance cover panel/service damage?
Damage from electrical fault often covered (sudden, accidental events). Aging-related degradation typically not covered (maintenance scope). Document with electrician report; submit claim and let insurance determine. Many Marin homes have had panel upgrade scope partially covered when triggering event was documented (fault, fire damage, surge event).
How long can I leave the main off?
For diagnostic purposes: hours to a day or two. Refrigerator and freezer contents have time limits (4 hours fridge, 24-48 hours freezer). Other house systems (heating, water if pumped) lose function. For extended diagnostic delays: arrange alternate accommodation or use battery/generator backup for critical loads. Most main breaker scenarios get diagnostic same-day or next-day to minimize duration.
How do you handle pricing — flat fee or hourly?
Both, depending on scope. Routine service calls and predictable scope (panel replacement, EV charger install, transfer switch install, fixture replacement) are flat-fee quoted up front. Diagnostic visits and emergency scope are hourly because we don't know what we'll find. Either way, you get a written quote before work starts on anything significant, and we don't proceed beyond the quote without your sign-off.
How quickly can you schedule?
Depends on scope and season. Emergency dispatch: same-day across Marin County (1-3 hours business hours, 1-4 hours after-hours). Same-day standard service: 3-6 hours from call when capacity allows; otherwise next business day. Scheduled service work: 1-3 weeks typical. Larger projects requiring permits and PG&E coordination: 4-12 weeks depending on scope. We're upfront about timeline at the quote stage.
What warranty do you offer on work?
Our standard residential warranty: 2 years on labor, manufacturer warranty on parts (varies by product — typically 1-10 years). Major installs (panels, generators, EV chargers) often have longer manufacturer warranties (5-10 years). If there's an issue with our work in the warranty period, we come back and fix it at no cost. We also stand behind work past warranty — repeat customers and referrals matter more than a transactional fix.
Are you licensed and insured?
Yes. California State License Board C-10 Electrical Contractor #989290, in good standing. Carry general liability insurance and workers' compensation insurance as required by California law. Bondable on projects requiring it. Happy to provide proof of insurance to clients or property managers on request. License lookup: cslb.ca.gov.
Same-day diagnostic visit in Marin.
We bring the right test gear and most common parts. Single-visit repair on roughly 80% of diagnostics.