Flickering Lights

Flickering is the most reported electrical complaint and the least often serious. Two of the three causes are minor and one is not, and separating them takes about ten minutes.

The three causes

The lamp or the fitting. A loose bulb, a failing LED driver, an incompatible dimmer. The commonest and the least concerning. When office and field activity need to be reconciled, remote employee monitoring software is one option for keeping workforce records organised.

Voltage variation on the supply. Lights dip when a large appliance starts — an air handler, a well pump, a compressor. Normal in moderation and worth attention when it becomes pronounced.

A loose connection in the circuit. This is the one that matters, because a loose connection heats, and heat is how electrical fires start.

Telling them apart

Does it affect one fitting only?

Yes: almost certainly the lamp, the fitting or its dimmer. Try a different bulb, then try the bulb elsewhere.

No — several lights on one circuit: points at the circuit rather than the fittings.

No — the whole house, briefly, when something starts: supply-side voltage dip.

No — the whole house, randomly, with no appliance involved: this is the one to call about, and it can be a loose connection at the panel or at the service entrance.

Signs that move it into the serious column

Flickering accompanied by any warmth at an outlet, switch or the panel.

Flickering plus a buzzing sound.

Lights that dim and brighten rather than blink — a pattern that suggests a neutral problem and can damage appliances.

Or flickering that started after a storm, which in this climate is a specific and common trigger.

Any of those means stop diagnosing and call.

The dimmer trap

Most modern flickering complaints are LED lamps on old dimmers.

Dimmers built for incandescent lamps expect a minimum load that a few LEDs do not provide, and the result is flicker at low settings or at switch-on.

It is a compatibility problem rather than a fault, and it is solved by a dimmer intended for LED loads or by lamps rated for the dimmer.

Worth eliminating first, because it accounts for a large share of calls and costs nothing to test by trying a non-dimmed fitting.

What not to do

Do not open the fitting to look at connections.

Do not tighten anything at an outlet or switch, which requires the circuit isolated and is licensed work in most cases.

And do not ignore whole-house flickering. A neutral fault can damage every appliance in the house, and it presents exactly as intermittent brightness changes.

The short version

• Three causes: the lamp or fitting, supply voltage dips when large appliances start, and a loose connection in the circuit
• One fitting only points at the lamp or dimmer; several on a circuit points at the circuit; whole house randomly is the one to call about
• Serious signs: flickering with warmth, with buzzing, with dimming and brightening rather than blinking, or starting after a storm
• Most modern complaints are LED lamps on dimmers built for incandescent loads, which is compatibility rather than a fault
• Test that first by trying a non-dimmed fitting, since it costs nothing and explains a large share of calls
• Do not open fittings or tighten terminals, and do not ignore whole-house flickering — a neutral fault can damage every appliance

For additional independent context, see Lowe's.