What size wire for an exhaust fan — and when it needs a 3-core drop

PILONE CABLES TECHNICAL TEAM

1.5 mm² copper — the wire shops sell as 3/.029 — because that is what the room's lighting circuit is already wired in. Take 3 core plus earth if the fan has a timer or a run-on, 2 core plus earth if it is switched on and off.

A kitchen or bathroom exhaust fan is 30–60 W, which is 0.14–0.27 A at 220 V. That current sizes nothing. What decides the cable at the point is the circuit it hangs off, the earth the fan's metal body needs, and the number of cores its switching wants.

The fan does not size the cable — the circuit does

An exhaust fan point in a Pakistani house is wired in 1.5 mm² copper on the room's 6–10 A lighting circuit, with the earth core carried through to the fan body, and with a third core where the fan runs on after the light is switched off. The fan's own load is negligible against that cable: 60 ÷ 220 = 0.27 A on a conductor rated 19.5 A clipped direct at 30°C. Nothing smaller is used, not because 0.27 A needs 1.5 mm², but because the whole circuit is pulled in one size and this point is part of it.

One ventilation fan point on a 220 V single-phase lighting circuit. Current capacity per BS 7671, reference method C (clipped direct), 30°C ambient, two loaded conductors; conductor and stranding data per IEC 60228. Derate for conduit, grouping and ambient above 30°C. Verify sizing with a licensed electrician for your installation.
Parameter	Value
Fixture	Kitchen or bathroom ventilation fan
Power, typical	30–60 W
Running current at 220 V	0.14–0.27 A
Circuit cable	1.5 mm² copper (3/.029)
Capacity of that cable	19.5 A
Cores, switched fan	2 plus earth
Cores, timer or run-on fan	3 plus earth
Breaker	6–10 A lighting MCB
Own circuit	No — shares the room's lighting circuit
Fixture tail	0.75 mm² 3 core flexible, rated 6 A

Why the third core, and why the earth is not optional

A plain fan takes a switched live and a neutral. A timer or run-on model needs both a permanent live, so its timer keeps counting, and a switched live that tells it the light went on — three current-carrying cores plus the earth. That is the single most common reason a fan is rewired six months after it is fitted: the drop was pulled in two cores and the fan on the box wanted three.

Run the numbers on the drop itself and you can see how little the length matters here. A 60 W fan 12 m from the switch loses 29 × 0.27 × 12 ÷ 1000 = 0.09 V in 1.5 mm². Voltage drop will never be what fails a ventilation fan. The earth might: kitchen and bathroom fans sit in damp, greasy air with a metal body and a metal grille, so the circuit protective conductor has to reach the fan and be terminated at it, not cut off in the ceiling box.

Take the point off the lighting circuit, not off a socket circuit — a 16 A socket breaker gives a 30 W fan no useful protection.
Add the fan's watts to everything else on that circuit before you add the point. The count of fixtures per circuit is worked through in the ceiling fan wire size guide.
In a bathroom, keep the fan and its wiring out of the wet zones and take the isolation from a pull cord or a fan isolator, as set out in the bathroom wiring guide.
The short flexible tail from the ceiling box into the fan is 0.75 mm² 3 core; it is a tail, not the circuit.

Current capacity depends on how the cable is installed. Derate for conduit, grouping, and ambient temperature above 30°C, and take the correction factors for your own method from BS 7671. Have a licensed electrician confirm the size for the whole circuit, not this one fixture — or start with the cable size calculator.

The cable for this job

Coils of single-core PVC-insulated copper wiring cable in red, black and green-yellow

1.5MM² · 3/.029 · 450/750 V · COPPER

1.5mm 3/.029 Copper Cable

Single-core PVC wiring cable, 450/750 V, drawn on the Pilone line in Lahore. Rated 19.5 A clipped direct at 30°C — the wire light and fan circuits are pulled in.

Factory-direct price

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Cable tracks the daily copper rate, so we quote per metre and per coil on WhatsApp. Send the length and your city.

For the flexible tail into the fan, 0.75mm 3 core flexible cable. For solid single-core light points, 1.5mm single core solid cable.

Frequently asked

Exhaust fan ke liye kitne mm ka wire chahiye?

1.5 mm² copper, jise dukaan par 3/.029 kehte hain, kyunke kamre ka light circuit isi mein pulled hota hai. Fan khud sirf 30–60 W leta hai, yani 0.27 amp tak. Earth core fan tak zaroor le kar jayen, aur agar fan timer wala hai to teen core plus earth chahiye.

Can I wire a fan point in 0.75mm cable?

Only as the short flexible tail from the ceiling box into the fan. 0.75 mm² is rated 6 A, which is under a 6–10 A lighting breaker once it is derated for conduit and grouping, so it is the wrong conductor for the circuit itself. The circuit stays 1.5 mm² from the distribution board.

Why does a timer fan need three cores?

Because it needs two lives. A permanent live keeps the timer powered so it can run on after you leave the room, and a switched live tells it the light was turned on. Add the neutral and that is three current-carrying cores, plus the earth. A plain switched fan needs only a switched live and a neutral, plus earth.

Does a bathroom exhaust fan need an earth?

Yes, wherever the fan has any exposed metal — and most kitchen and bathroom fans have a metal body or grille. Take the circuit protective conductor all the way to the fan and terminate it there. Keep the fan and its wiring clear of the wet zones, and isolate it with a pull cord or a fan isolator.

1.5mm cable for the light and fan circuit, at the factory rate

We draw the copper in Lahore and sell it at the day's rate — no dealer margin. Tell us the metres and your city: Punjab in 1–2 days, rest of Pakistan in 2–4.

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