Flickering lights are usually one of a few things: a loose or wrong bulb, a large appliance pulling power when it turns on, a loose wire connection, or an overloaded or failing circuit. Most causes are minor, but some point to a loose connection or a bad panel, and those can start a fire.
This guide walks through the common causes, which ones are no big deal, and which ones mean you should call an electrician right away.
Why is one light bulb flickering?
A single bulb that flickers is almost always the bulb or the fixture, not your wiring. Start here before you worry.
Common reasons one bulb flickers:
- The bulb is loose in the socket. Turn the power off and screw it in tighter.
- The bulb is worn out. LED and old bulbs flicker near the end of their life.
- You put an LED bulb on a dimmer made for old bulbs. Many dimmers do not work with LEDs.
- The socket contacts are dirty or bent.
Why do my lights flicker when an appliance turns on?
Lights that dim or flicker when a big appliance starts up are often normal, but it can mean your panel is undersized. Things like an AC unit, a fridge, a microwave, or a well pump pull a lot of power the moment they kick on. That quick draw can make your lights blink for a second.
A short blink once in a while is usually fine. But if it happens a lot, or the dimming is strong, it can mean:
- The appliance is on the same circuit as your lights and should be moved.
- Your electrical panel is too small for your home's needs.
- A connection somewhere is loose.
Are flickering lights a sign of a loose wire?
Yes, and this is the cause to take seriously. A loose or failing wire connection at an outlet, switch, light fixture, or in your panel is a real fire risk. Loose wires arc and spark, and that heat builds up over time.
Signs the problem is a loose connection:
- The flicker is at one fixture, outlet, or switch and bulbs do not fix it.
- A switch plate or outlet feels warm or hot.
- You smell something burning or like hot plastic.
- You see scorch marks or hear buzzing or crackling.
How serious is each cause?
Here is a quick look at the common causes and how worried you should be.
| Cause | How serious |
|---|---|
| Loose bulb or wrong dimmer | Minor, easy fix |
| Big appliance starting up | Usually minor, can mean small panel |
| Loose wire at outlet or switch | Serious, fire risk, call now |
| Overloaded circuit | Serious, needs a fix |
| Old or failing panel | Serious, fire risk |
| Federal Pacific panel | Serious, replace it |
| Utility or service problem | Call utility, then an electrician |
Can an overloaded circuit cause flickering?
Yes. An overloaded circuit happens when you plug too much into one circuit, so it cannot keep up. Lights on that circuit may dim or flicker, and breakers may trip.
This is common in older homes with fewer circuits. The fix is usually adding a new circuit or spreading the load out. It is not something to ignore, because a circuit running hot all the time can fail.
Is my whole house flickering? When to worry.
If lights flicker across your whole house at the same time, stop and pay attention. This is not a single bulb problem. It points to your main panel, your main service connection, or the power coming from the utility.
Call right away if you notice:
- A burning smell anywhere near outlets, switches, or the panel.
- A switch plate, outlet, or the panel that feels warm or hot.
- Flickering across the whole house, not just one room.
- Buzzing, crackling, or scorch marks.
What about old or Federal Pacific panels?
An old panel can cause flickering all on its own. Federal Pacific panels are a known hazard. Their breakers often fail to trip when they should, which means they may not protect your home during an overload. If you have one, it should be replaced.
A panel that is rusted, full, or making noise is also a warning sign. An [electrical inspection](/services/electrical-inspections/) finds these problems before they become a fire.
Could it be the power company?
Sometimes the flicker is not your fault at all. If your neighbors also notice flickering or dimming, the issue may be on the utility side. PSE&G and JCP&L handle the lines and the connection up to your meter.
Call your utility first to check. If they say everything on their end is fine, the problem is inside your home, and that is when you call an electrician.
We find the real cause, not just the symptom
I am Bruce Harrelson, owner of Harrelson Electric. I have been a Master Electrician since 1988, and I hold NJ License #15918. We are bonded and insured, and I do the work myself. No subcontractors.
Flickering lights have many causes, and the dangerous ones hide behind the simple ones. We do not just swap a bulb and leave. We trace the flicker back to the real source, whether that is a loose wire, an overloaded circuit, or a panel that needs to go.
If your lights are flickering and a new bulb did not fix it, call me at (800) 732-0585 for a free estimate. We serve Central NJ from our shop in South River. If it is minor, I will tell you. If it is a safety issue, we will fix it right.