Lights flickering all over the house? When it's a duff bulb and when I'd want to see it today

Flickering lights are one of those problems that sit right across the whole worry scale. At one end it's a 90p bulb on its way out... genuinely nothing. At the other, it's a loose connection quietly cooking behind your meter, which is a job I'd want to look at the same day. The trick is knowing which end you're at, and the honest answer is that it's mostly about how much of your house is flickering.

So let me walk it up the scale, from "leave it" to "call someone today".

One light flickering: almost always the bulb, fitting or dimmer

If it's a single light playing up and the rest of the house is rock steady, relax... the fault is nearly always at that one fitting.

• The bulb. LEDs flicker as they fail, just differently from the old filament ones... a shimmer or a stutter rather than a slow fade. Swap it for a known-good bulb first. It's free and it settles most cases on the spot.

• A loose bulb or tired holder. A bulb not quite home, or an old holder with weak contacts, gives an intermittent connection and a flicker. Turn it off, let it cool, and nip it a bit tighter.

• The dimmer. This is the big one people don't expect. Put modern LED bulbs on an old dimmer switch and they'll often flicker, buzz, or refuse to dim down low... because most older dimmers are "leading-edge" types designed for the heavy load of filament bulbs, and LEDs draw a fraction of that. The fix is usually a trailing-edge dimmer made for LED loads, paired with bulbs the maker actually lists as dimmable. Get that combination wrong and no amount of new bulbs will settle it.

If a new bulb and a quick check of the fitting sorts it, that's the end of the story. Sorting out dimmer-and-LED mismatches, or replacing a worn fitting, is bread-and-butter lighting work if you'd rather not.

One room flickering: still usually fixable, but worth a proper look

If a whole room flickers together, but the rest of the house is fine, I'm thinking about that room's circuit rather than any one bulb. A loose connection at a switch, a junction box, or the first fitting on the run can make everything downstream of it flicker. It's contained, it's not usually an emergency, but it does want opening up and checking rather than ignoring, because a loose connection is a loose connection wherever it lives.

Whole house flickering, or lights dimming when the kettle or shower kicks in: this is the serious end

Here's where I change my tone. If lights all over the house flicker together, or they visibly dip when a big load switches on (the shower, the kettle, the oven, the washing machine reaching its heat cycle) that points at something upstream that feeds the whole property. And that's the category I'd want eyes on quickly.

A small, momentary dip when a 9kW shower fires up isn't unheard of. But a pronounced dim, one that lingers, or one that's clearly getting worse over weeks, usually means a high-resistance connection somewhere in the main supply path... a loose or corroded meter tail, a tired connection at the consumer unit's main switch or busbar, or a poor joint at the cut-out. A connection like that doesn't just flicker your lights; it heats up at the loose point. That's the bit that matters. Warmth, a faint fishy or burning smell, buzzing, or any browning around the meter or fuse box turns this from "book me in" into "switch it off and call me today", because a hot joint at that kind of current is a real fire risk, not a nuisance.

This isn't scaremongering... most whole-house flicker turns out to be fixable and safe once found. But it's the one symptom on this page I won't tell anyone to sit on, and I genuinely can't judge severity down the phone. Tracing it means measuring at the board and working back, which is what my fault-finding service is built around.

Is it even your problem to fix? The "call 105" test

Before you assume it's your wiring, do one quick check: look out the window, or ask a neighbour.

The dividing line runs at your cut-out (the main service fuse). Everything from the meter into your home (your tails, your consumer unit, your circuits) is yours to sort, and that's where an electrician like me comes in. But the service cable and cut-out feeding the street belong to your DNO, the company that owns the wires (not whoever you pay your bill to).

So:

• Only your house flickers? That points inward, to your installation. That's my side of the line.

• The whole street flickers, or neighbours are affected too? That points to the network... often a failing shared neutral out in the road, which can swing the voltage and is exactly the kind of fault that damages electronics. That's a DNO job, and you report it free by dialling 105 from any phone, day or night. Give them your postcode. Don't waste time ringing your energy supplier... they don't own the wires and can't fix it.

If you're not sure which side you're on, that's a fair thing to be unsure about, and it's a five-minute thing for me to establish rather than something to lose sleep over.

Why I see so much of this around Bracknell

The classic pattern I see in the Bracknell new-town streets is whole roads built and wired in the same year back in the sixties and seventies... which means the connections in every house are the same age, doing the same job, and quietly ageing together. When one property on a street of identical builds starts getting flicker or warm connections, it's rarely a one-off. The materials tire, terminals that were nipped up decades ago work slightly loose with years of heating and cooling, and the symptoms turn up across the neighbourhood within a few years of each other. If your street is one of those and your lights have started dipping, you're not imagining it and you're not the only one.

An older installation like that is also worth a periodic check for its own sake... a proper inspection and test finds the tired connection before it announces itself with a smell.

The short version

• One bulb or one fitting flickering... try a good bulb, check the dimmer's LED-compatible. Usually nothing.

• One room... likely a loose connection on that circuit; get it looked at, no panic.

• Whole house, or dimming under load... treat it seriously, especially with any warmth or smell. Same-day if it's warm.

• Whole street... network fault, dial 105, not your supplier.

If your lights are flickering and you're not sure where on that scale you sit, I'd rather you asked than guessed. I'm a NAPIT-registered electrician based in Slough, covering Windsor, Maidenhead, Bracknell and across the Thames Valley. For a free, no-obligation quote, get in touch at bphelectrics.co.uk.