· by Michael Blair, Nashville's Electrician
Flickering lights get dismissed because they usually are nothing: a bulb on its way out, a dimmer that does not like LEDs, a ceiling fan light that vibrates its own connection loose. But a few patterns of flicker are the earliest warning of a failing connection that carries the whole house, and those connections fail hot. The way to sort one from the other is to notice exactly which lights flicker, when, and whether anything else in the house changes at the same moment.
Flicker that is almost always harmless
One fixture, one bulb: swap the bulb. If it is an LED on a dimmer, the dimmer is probably not rated for LEDs or the bulb is not dimmable, and the fix is a compatible dimmer. Fluorescent tubes flicker as they age and in cold garages. Smart bulbs flicker when a switch somewhere is cutting their power.
A brief dim when the refrigerator, the dryer or the air conditioner starts is normal on most houses. Motors draw a heavy inrush current for a fraction of a second, and the voltage drop shows in the lights. It should be a quick dip, the same size every time, and then nothing.
Flicker that needs an electrician this week
Lights on several circuits flickering together, or the whole house dimming and brightening with no appliance starting, point at a loose or corroded connection on the service itself: at the meter, the main lugs in the panel, or the splice at the weatherhead where the utility drop meets your wires. Those connections carry the full house load, and a loose one heats, arcs and eventually burns.
The most serious version is a loose neutral. With a poor neutral, the two halves of the house are no longer held at equal voltage, so some lights go bright while others go dim, often as a large appliance switches on or off. That can push well over normal voltage into one side of the house and burn out electronics, and it is a fire risk at the connection. Bright-and-dim at the same time is the tell.
- Several circuits flickering together
- Some lights bright while others dim
- A buzzing, crackling or hot smell at the panel or meter
- Flicker that gets worse in wind or rain, pointing at the outdoor splice
- Breakers that are warm to the touch
Where the fault usually is on a Nashville house
On older homes with overhead service, the splices at the weatherhead are exposed to decades of weather and are a common failure point; flicker that appears in wind or heavy rain is the classic sign. Aluminum branch wiring from the late 1960s and 1970s loosens at terminals as it expands and contracts, and a flickering fixture on an aluminum circuit means a connection that needs the proper connector, not just tightening.
Inside the panel, a loose neutral bar screw or a corroded main lug does the same thing. Certain older panel brands have known problems with bus bar connections and breakers that do not trip, and flicker in a house with one of those is a reason to talk about replacement rather than repair.
Who to call, and what they will do
If the flicker is house-wide, call the utility first. NES will check the drop, the meter base connection and the transformer without charge, and a fault on their side of the meter is theirs to fix. If they find the service sound, the fault is on your side, and an electrician opens the panel, checks the main lugs and neutral, and tightens or replaces what has failed. Any work at the service or in the panel needs a permit and inspection through Metro Codes.
Do not put it off until something else fails. A loose connection carrying the whole house gets hotter every time load passes through it, and the failure mode at the end of that process is not a blackout.