Flickering lights are sometimes serious.
Flickering lights range from harmless (LED dimmer compatibility) to dangerous (failing neutral connection at the service entrance). This guide helps you tell the difference and decide when professional diagnosis is required.
By Steven Lockhart · Reviewed by Alex Towery, C-10 #989290
Updated 2026-06-16
Flickering lights are common and the cause spectrum runs from trivial (cheap LED with old dimmer — fixable yourself for $20) to serious (failing service-side neutral connection — can damage every appliance in your house). Pattern recognition matters: which lights, when, what else is happening. This guide walks through the diagnosis.
01The seven pattern types — what each one means.
Single fixture flickering when switched on: usually LED-dimmer incompatibility or a failing bulb. Try a known-good incandescent or replacement LED. Low risk, often fixable for $20 in bulb cost.
Whole-house flicker when large appliances start (HVAC, fridge compressor, pump): often a service-side or panel-side issue. Could be normal voltage sag on a smaller service, or could indicate a failing neutral connection at the meter or service entrance. The latter is dangerous — can damage every appliance in your house — and requires same-day diagnosis.
02Diagnostic patterns to look for.
Whole-house simultaneous flicker
Service-side issue — possibly a failing neutral. Same-day diagnosis required. Can escalate to phase imbalance that damages appliances and electronics throughout the house.
Single circuit flicker
Loose connection somewhere in that circuit, or failing breaker, or shared neutral conflict with adjacent circuit. Schedule diagnosis within a few days.
Single fixture flicker only
Bulb, fixture, or dimmer compatibility issue. Try replacement bulb first, then consider dimmer compatibility (some LEDs require LED-rated dimmers). Low urgency.
03When flickering is dangerous.
Whole-house flickering — especially when correlated with large appliances starting — can indicate a failing neutral connection somewhere between PG&E's transformer and your panel. When a neutral fails, current that should return via the neutral instead returns via grounding conductors and equipment chassis, causing voltage imbalances between the two 'sides' of your 240V service. This can over-voltage one half of your house (damaging electronics) while under-voltaging the other half (damaging motors). Failures can cascade fast.
If you observe whole-house flickering correlated with appliance starts, treat it as a same-day electrical emergency. We respond to these calls as priority dispatch and typically diagnose within 60-90 minutes. Confirmed failing neutral usually requires PG&E coordination (if the failure is service-side) plus our work to verify panel-side integrity.
Common questions.
Is occasional flickering normal?
Brief flicker when a large appliance starts (HVAC compressor, sump pump, well pump) is common and usually not concerning — these draw heavy starting current for a moment, causing slight voltage sag. If it's brief (under a second) and only happens at appliance starts, it's typically normal. If it's longer, more frequent, or happens without an obvious trigger, schedule diagnosis.
Could it be a bad lightbulb?
Sometimes yes — particularly for LED bulbs in older dimmer circuits, or for bulbs that are end-of-life. Try a known-good bulb in the flickering fixture as a first step. If the flickering follows the bulb to other fixtures, it's the bulb. If a new bulb still flickers in the original fixture, it's the fixture or wiring.
Are LED bulbs more prone to flicker?
Yes — LEDs flicker more visibly than incandescents because their light output is more sensitive to small voltage variations and dimmer-circuit compatibility issues. If you've recently switched to LED bulbs and noticed new flickering, the cause is often dimmer incompatibility. Upgrade to LED-rated dimmers (Lutron Caseta, Leviton DSL06-1LZ, similar) and the problem usually resolves. We can recommend specific dimmer/bulb combinations during diagnostic visit.
What does the diagnostic visit cost?
Diagnostic flat fee runs $240-$420 in Marin (varies by AHJ, distance, time of day). Includes systematic flickering pattern assessment, panel inspection, and voltage measurements as needed. If we identify the issue during diagnostic, simple corrections (dimmer swap, bulb compatibility) often complete in the same visit at no additional charge. Larger remediation gets full written quote before work proceeds.
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.