Flickering lights in multiple rooms

Most flickering has a boring explanation. A globe that is not seated properly, a dimmer that was never meant for LEDs, a fitting that has worked loose. If it is one light in one room, start there and you will usually be done.

It changes when the flicker shows up in more than one room. Separate lights do not go faulty at the same time by coincidence. When several flicker together they are telling you about something they have in common, and that is either a shared circuit, the switchboard, or the supply coming into the house.

Work out how far it spreads

Before anything else, pay attention to the pattern. It is the most useful thing you can hand an electrician.

• One light, one room. Almost always the globe, the fitting or the dimmer.
• Several lights, one room. Often the one circuit, or the switch feeding it.
• Lights in different rooms at the same time. Something shared. This is the one worth looking at properly.
• Everything dips when an appliance kicks in. A load problem rather than a lighting problem.
• Worse in wind or rain. Points outside, towards the service line or the connection at the house.

What it usually turns out to be

• A loose neutral. The connection that balances your circuits has worked loose, often at the switchboard. Lights across the house dim and brighten slightly out of step with each other. This one matters, because a loose neutral can let voltage swing high enough to damage appliances.
• An overloaded or shared circuit. Lighting sharing a circuit with something that draws a big gulp of current on startup, like an air conditioner, a pump or an old fridge. You see a dip at the moment it starts.
• An ageing switchboard. Older boards with ceramic fuses and worn connections develop resistance at the terminals. Flickering is often the first symptom anyone notices.
• The supply itself. Sometimes the fault is not in your house at all. A failing connection on the street side produces the same symptoms, and that is the distributor's job to fix rather than something you pay for.

When it is not something to sit on

Flickering is usually a nuisance rather than an emergency. These are the exceptions, and they are worth acting on the same day.

• A burning smell anywhere near the switchboard, a switch or a power point
• A switch, outlet or faceplate that feels warm
• Scorch marks or browning around a fitting
• Flickering that started alongside a buzzing sound at the board
• Lights surging bright rather than just dimming

Any of those means stop reading and get someone out. Turn the affected circuit off at the switchboard if you are comfortable doing it.

What you can check first

• Note which rooms, and whether it happens at a particular time of day
• Check whether it coincides with an appliance starting up
• Try a known good globe in one of the affected fittings
• If the flickering lights are on dimmers, check the globes are actually dimmable, because a lot of LEDs are not
• Ask a neighbour whether they have noticed anything, which is the quickest way to tell a supply problem from a house problem

What we do about it

Diagnosing a flicker is mostly elimination. We check the pattern you have noticed, test voltage under load rather than at rest, because a loose neutral often looks perfectly healthy until the house draws current, and work back from the affected circuits to the switchboard.

If it turns out to be the supply rather than your wiring, we will tell you that, and the fix goes to your distributor instead of to us. We would rather say so up front than hand you a bill for finding it out.