A single light that flickers is usually a bulb, a dimmer or a loose connection at that fixture. When lights flicker in several rooms at once, or across the whole house, the cause is upstream of the fixtures: in the panel, in the service coming into the house, or on the utility's side. Some whole-house flicker is harmless. Some is an early warning of a connection that is failing. Here is how to tell the difference.
First, narrow it down
Where the flicker happens tells you a lot:
- One fixture: a bulb, an LED that does not match its dimmer, a worn switch or a loose connection at the fixture. See lighting repair.
- One room or one circuit: a loose connection at an outlet, switch or splice on that circuit, or at its breaker.
- The whole house: something shared by every circuit. That means the main connections in the panel, the service conductors, the meter, or the utility supply.
Flicker that is usually normal
A brief dip in brightness when a large motor starts, most often the air conditioning compressor, is common. The motor draws a burst of current for a moment as it starts, and lights on the same service dim slightly. If the dip is short, happens only when the AC kicks on, and has not changed over time, it is usually not a concern.
It is worth a look if the dip has become more noticeable than it used to be, lasts more than a moment, or happens when nothing large is starting. A connection that is loosening adds resistance, and resistance makes every dip deeper.
Flicker that needs attention
Call an electrician soon if whole-house flicker comes with any of these:
- Some lights get brighter while others dim at the same moment.
- Electronics or LED bulbs failing more often than usual.
- Flicker that is getting more frequent, or happens in wind or rain.
- A warm panel, a buzzing sound at the panel or the meter, or a burning smell.
- Part of the house losing power now and then.
Brightening and dimming together is the most important sign. It can mean the neutral connection shared by both halves of the service has loosened or failed. Without a solid neutral, the voltage on each half of the house drifts with the load: lightly loaded circuits rise, heavily loaded ones sag. That can damage appliances and electronics quickly, and it is a heat problem at the point of the bad connection. If you see it, turn off sensitive electronics and call. Our post on half the house losing power explains the two-sided service in more detail.
Is it FPL or your house?
Check with a neighbor. If their lights flicker at the same times, the cause is likely on the utility side, such as a line, a transformer, or vegetation touching lines in wind. Report it to FPL at 1-800-4OUTAGE (1-800-468-8243) or through the FPL app.
If it is only your house, the cause could still be on either side of the meter. In general, FPL is responsible for the lines and equipment that bring power to your meter, and the homeowner is responsible for the electrical system from the meter into the house: the meter enclosure, the service conductors, the main breaker and the panel. An electrician can test at the panel and tell you which side the problem is on. If it is FPL's, you can report it with specifics. Our guide to telling FPL problems from house problems goes through the same logic for outages.
What we check
For whole-house flicker, we start where every circuit meets. We look at the main breaker and the main lugs in the panel for heat or discoloration, check the neutral and ground connections, and measure voltage on both sides of the service, at rest and under load. If the panel looks good, we move outward to the meter enclosure and the service entrance, where weather and salt air can work on connections over the years. If the readings point to the supply, we tell you what to report to FPL.
What not to do
- Do not open the panel cover or the meter enclosure. The main connections stay energized even with the main breaker off.
- Do not ignore flicker that comes with heat, smell or sound.
- Do not assume new LED bulbs will fix whole-house flicker. If every room flickers, the bulbs are reporting the problem, not causing it.
Questions people ask
Can LED bulbs cause flicker across the whole house?
Not on their own. LEDs show small voltage changes that older bulbs hid, so they can make an existing problem easier to see. If every room flickers at the same moment, the cause is shared by every circuit, and that is where to look.
Is flicker during storms normal?
Brief flicker during a storm often comes from the utility side, as lines move in the wind or equipment switches to reroute power. If it happens only at your house, or only in wet weather, it can point to water or corrosion at the service entrance, which is worth checking.
Need it looked at?
KRW Electric (EC13012832) troubleshoots and repairs flickering lights and power problems in Pinecrest, Coconut Grove, South Miami and Miami Beach, with same-day service when scheduling permits. Call (305) 359-7312 and tell us what you are seeing. We will ask a few questions, tell you whether it sounds urgent, and give you the earliest time we have. Our before you call checklist covers what to have ready, and what happens on a repair visit explains the rest.
Reviewed by Kyle White, KRW Electric Company LLC — licensed electrical contractor EC13012832.
