What usually causes this?
Startup current
Motors in AC units, refrigerators, pumps and vacuums draw extra current when starting.
Shared circuit
Lights and heavy appliances on the same circuit amplify the effect.
Loose connections
Resistance at connections increases voltage drop.
Service near capacity
Homes adding big loads can push the service to its limit.
Utility transformer
Shared transformers can cause dips when neighbors' loads start.
What you can safely check
These details help an electrician find the cause faster. Look and listen only — do not remove covers or touch wiring.
- Which appliance triggers it
- Whole-house versus single-room dimming
- Duration of the dimming
- Time of day
- Whether it's getting worse
Warning signs that need a professional
- Dimming that lasts or worsens
- Lights brightening unusually
- Buzzing or warm panel
- Breakers tripping
- Burning smell
When should you call an electrician?
If dimming is more than a quick flicker, or it's getting worse, have an electrician check. Solutions include dedicated circuits for large appliances, tightening connections, or a panel upgrade if the service is undersized.
Services that fix this problem
Electrical Troubleshooting
Systematic testing to find the cause of intermittent power loss, tripping, flickering and other electrical faults that aren't obvious.
Electrical Wiring
New circuits, repairs to damaged wiring and wiring updates for kitchens, additions and major appliances.
Electrical Panel Upgrade
Increasing your home's electrical capacity — typically 100A to 200A — for EV chargers, heat pumps, additions and modern loads.
Electrical Panel Services
Repairs, inspections and maintenance for breaker panels — loose connections, damaged breakers, labeling and capacity checks.
Related electrical problems
Frequently asked questions
A brief, slight dip can be normal. Noticeable or long dimming isn't and should be checked.
Often. Moving a large appliance to its own circuit reduces the effect on lighting.
Not necessarily. A load review determines whether the service is the issue or a specific circuit is.