Why Are the Lights Flickering in My House? A Delhi Diagnosis

First question: is it one light, one room, or the whole house?

This single question splits the problem into three very different jobs. Answer it before anything else.

• One light only. Almost always the bulb, the holder or the LED driver inside the fitting. Cheap LED bulbs and panels flicker as their internal driver fails, and they usually flicker faster and faster over a few weeks. Low risk. Swap the bulb for a known-good one and see.
• One room, or one set of lights on the same switchboard. Now you are looking at a shared connection — a loose terminal in that board, or a joint in the wiring feeding that room. This is not a bulb problem, and it is the classic cause of a burnt switchboard later.
• The whole house at once. Either the incoming supply is fluctuating (common in Delhi, and usually not your fault) or there is a loose neutral, which is the dangerous one. The next two sections tell them apart.

Write down what you see for a couple of days before calling anyone. “Only the bedroom lights, only when the AC is on” is worth more to an electrician than an hour of hunting.

The dangerous one: a loose neutral

Plain English first. Every circuit in your flat needs two paths: one bringing current in (live) and one taking it back (neutral). If the neutral connection is loose — at a joint, at the switchboard, or where the supply enters the flat — the voltage across your lights stops being steady. It wanders, and it wanders differently in different rooms depending on what is switched on.

The tell-tale signs, and they are quite specific:

• Lights in one room go dim exactly when lights or an appliance in another room come on. A see-saw. That is the signature.
• Some lights get brighter while others get dimmer. Very few faults do this. A loose neutral does.
• Bulbs keep failing early in the same few fittings, and you have replaced them more than once.
• A switchplate, socket or the board feels warm, or there is a faint hot-plastic smell near it.
• A faint buzzing or crackling from a switchboard or fitting.

A loose connection is a resistance, a resistance carrying current makes heat, and the heat is inside a wall where you cannot see it. That is why this one is not a “next month” job.

The Delhi one: voltage sag and overloaded circuits

If the whole flat dips together, briefly, at predictable times, you are probably watching the supply rather than a fault. This is extremely common across Delhi NCR and it has a very clear seasonal shape.

• Summer afternoons and evenings. Every AC in the colony is running, the local network is loaded, and the voltage reaching your flat sags. Lights dim; fans slow slightly; the fridge sounds like it is straining.
• A dip exactly when the AC, fridge, water motor or geyser starts. Motors draw a large surge for a fraction of a second when they start. A brief dip is normal. A dip so deep the lights visibly drop, every single time, means the circuit or the incoming supply is marginal.
• Winter smog season, evenings. Room heaters and geysers across the building do the same thing summer ACs do, on wiring that was never designed for either.
• Older flats with aluminium wiring. Aluminium joints loosen over the years as they heat and cool, which is why so many pre-2000 Delhi flats develop flicker in exactly the rooms that got new appliances.

How to tell supply sag from a fault inside your flat: ask a neighbour. If their lights dip at the same moment yours do, it is the incoming supply and the answer is protection (a stabiliser on the sensitive equipment) rather than rewiring. If yours dip and theirs do not, the problem is on your side of the meter. Our guide to voltage fluctuation and what actually needs a stabiliser covers which appliances need protecting and which do not.

What you can safely check yourself, for free

All of this is free, needs no tools, and involves no wiring. Do it before you call anyone.

• Swap the bulb. Take a bulb you know works from another room and put it in the flickering fitting. If the flicker moves with the bulb, you are done. Do this with the switch off.
• Check for a dimmer or a regulator. Many LED bulbs are not dimmable and flicker badly on an old dimmer or a fan-type regulator. Set it to full and see if the flicker stops.
• Watch the clock. Note the time every time it happens for two or three days. A pattern that follows the afternoon, the evening, or the AC switching on is a load or supply story.
• Watch what else moves. Do the fans slow at the same instant? Does the fridge click? Does the TV picture shrink? Whole-flat behaviour points at supply or neutral, not at that bulb.
• Isolate by switching off, not by opening anything. Turn off the circuit breakers one at a time at the distribution board and note which one kills the flickering lights. Naming the circuit saves an electrician real time. Switching breakers on and off is safe; opening the board is not.
• Feel switchplates with the back of your hand. Warm is a finding. Report it, do not investigate it.

If the flicker is on one light and moves with the bulb, stop here — you have fixed it. If it does not, you now have a much better description to hand over.

When to stop and call an electrician

Call someone the same day if any of these is true. These are not wait-and-see symptoms.

• Lights in one room dim when something in another room switches on, or some get brighter while others dim.
• Any switchplate, socket, plug or the distribution board is warm or hot.
• You can smell hot or burning plastic, or see brown or black scorching anywhere.
• You hear buzzing, crackling or sizzling from a board or fitting.
• The flicker started along with a breaker tripping — see why an MCB keeps tripping and why an RCCB trips.
• Anyone has felt a tingle from a switch, appliance or tap. Treat that as urgent — read what a shock from a tap or appliance means.

What the electrician will actually do is tighten and re-terminate connections at the board and the affected switchboards, check the neutral, and measure the voltage under load. If the flat is old and the flicker is everywhere, they may raise rewiring — our page on the signs house wiring needs replacing lists the symptoms that genuinely justify it, and what electricians charge in Delhi NCR covers how these visits are usually billed.