Partial outage = specific failure modes.
Power on some circuits but not others is a different problem than total outage. Three common causes: lost service leg (one of two utility lines failed), open neutral (lights flicker or appliances behave oddly before going dead), or breaker/panel issue on a specific bus.
By Steven Lockhart · Reviewed by Alex Towery, C-10 #989290
Updated 2026-06-16
Partial outages have specific causes: (1) Lost service leg — one of the two 120V utility hot legs has failed at PG&E side or at service entrance. Half of 240V panel is dark. (2) Open neutral — connection problem between utility neutral and panel neutral; symptoms include flickering before failure, appliances running at wrong voltage. (3) Specific breaker or bus issue. Call electrician same-day; partial outages create voltage anomalies that can damage appliances.
01What 'partial' actually means.
US residential power comes from PG&E as 240V split-phase — two 120V hot legs and a neutral. Your main panel has two bus bars; one connects to each hot leg. Breakers alternate between buses going down the panel. If one hot leg fails, half of your breakers (every other one) go dead. Big 240V loads (range, dryer, AC) lose power because they need both legs. The other half of breakers continue working from the surviving hot leg.
An 'open neutral' is more dangerous than a missing leg. Without proper neutral, voltage at the panel becomes unbalanced — some circuits see voltage above 120V (potentially damaging electronics), others below. Symptoms include lights brightening then dimming, appliances behaving erratically, sometimes a burning smell from overloaded electronics. Open neutral requires immediate response (turn off main breaker until electrician arrives) — extended operation with open neutral destroys electronics.
02Diagnosis and response.
Document the pattern
Note which circuits work and which don't. Take photos of the panel showing which breakers are which. The pattern helps the electrician diagnose faster — alternating dead breakers suggests lost leg; specific area dead suggests sub-panel or branch issue; flickering before failure suggests open neutral.
For lost service leg
Call PG&E (1-800-743-5000) — service leg failures are often utility-side. PG&E investigates and repairs if grid side. If PG&E identifies homeowner-side issue (service entrance, meter base on homeowner side), they refer to electrician.
For suspected open neutral
Turn off main breaker immediately. Don't operate appliances until diagnosed. Call electrician same-day. Open neutral can damage electronics quickly (minutes to hours of operation can fry sensitive equipment). Turn off main, wait for diagnosis.
03Cost and timeline expectations.
Diagnosis call: $200-$350 typical for emergency dispatch. If issue is utility-side, PG&E handles repair at no cost to homeowner. If issue is homeowner-side: service entrance repair $600-$1,800; main panel repair (breaker replacement) $400-$900; full panel upgrade if panel-side issue is severe $3,500-$6,500. Most partial outages resolve in same-day diagnostic visit with same-day or next-day repair.
Timeline: dispatch typically 1-3 hours from call during business hours, 1-4 hours after-hours. Diagnosis 1-2 hours on-site. Repair varies by scope — small repairs same visit, larger scopes typically next-day with permit if required. Marin AHJs are responsive to emergency permit requests for safety-critical work.
Common questions.
Can I keep using the circuits that still work?
Generally yes — for short periods (hours to a day at most). Avoid running large 240V loads (range, dryer, AC). Avoid plugging sensitive electronics into still-working outlets if you suspect open neutral. The safest approach: turn off main breaker and wait for electrician. Working with partial power risks further damage to electronics and obscures diagnostic clues.
Why does my refrigerator still work but my microwave doesn't?
They're on different circuits, and one circuit's breaker is on a hot leg that's still energized while the microwave's breaker is on the dead leg. Modern panels alternate breakers between the two legs going down — adjacent breakers feed from different legs. The pattern of working vs dead appliances reveals which leg is dead and helps diagnosis.
Will my homeowner's insurance cover appliance damage from open neutral?
Often yes for electronics damage from documented electrical failures, depending on policy. Document carefully: time of issue, symptoms observed (flickering, etc.), professional diagnosis from electrician, list of damaged appliances. Insurance claims work better with clear electrician documentation. Some policies exclude appliance damage; check yours.
Is this a common issue in Marin?
Open neutrals are uncommon but happen, often after storms or with aging service entrance hardware. Lost service legs are slightly more common, especially in West Marin where some service drops are older. Both are routine for emergency electricians in Marin. Modern service entrance hardware and regular inspection reduce risk.
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.
Emergency response across Marin County.
Same-day dispatch for safety scenarios. Typical on-site time 1-3 hours weekday, 1-4 hours after-hours.