What cable for bathroom and washroom wiring?

PILONE CABLES TECHNICAL TEAM

Lights and the exhaust fan on 1.5 mm² — the wire sold as 3/.029 — on a 6 A MCB. Any socket on 2.5 mm² (7/.029) at 16 A sited outside the wet zone, the geyser on its own circuit back to the board, and the whole room behind a 30 mA RCD.

A bathroom is the lightest room in the house electrically and the most dangerous one. Its lighting circuit runs at well under an amp, so ampacity is never the deciding question here — placement, earthing and the geyser feed are.

Bathroom wiring cable size, point by point

A washroom in a Pakistani house on a 220 V single-phase supply takes 1.5 mm² copper for lights and the exhaust fan on a 6 A MCB, 2.5 mm² for a socket outlet on 16 A, and a dedicated circuit for the water heater sized to the element on its rating plate — 2.5 mm² for a storage geyser, 4 mm² for an instant one. Every point is earthed, and the room's circuits sit behind a 30 mA residual current device. Those sizes hold for a normal run in conduit; past about 13 m to the geyser, voltage drop takes over, which is worked through below.

Copper conductors, PVC insulated, 450/750 V. Current capacity per BS 7671, reference method C (clipped direct), 30°C ambient; conductor and stranding data per IEC 60228. Wattages are typical — read the rating plate on your own heater. Derate for conduit, bunching and summer ambient. Verify sizing with a licensed electrician for your installation.
Bathroom point	Typical load	Cable (strand code)	Capacity	MCB
Ceiling or shower light	10–60 W	1.5 mm² (3/.029)	19.5 A	6 A
Mirror or vanity light	10–40 W	1.5 mm² (3/.029)	19.5 A	6 A
Exhaust fan	30–60 W	1.5 mm² (3/.029)	19.5 A	6 A
Socket, outside the wet zone	up to 2000 W	2.5 mm² (7/.029)	27 A	16 A
Storage geyser point	1500–3000 W	2.5 mm² (7/.029)	27 A	16 A, dedicated
Instant geyser point	3000–4500 W	4 mm² (7/.036)	36 A	25 A, dedicated
Earth conductor to the bathroom	—	6 mm² (7/.044)	46 A	—

The fork on the geyser row is arithmetic, not preference: a 3000 W storage element draws 3000 ÷ 220 = 13.6 A, which 2.5 mm² at 27 A carries with margin, while a 4500 W instant heater draws 4500 ÷ 220 = 20.5 A and needs 4 mm² at 36 A. Take the wattage off your own plate and read the size ladder on the geyser wire size guide or, for a tankless unit, the instant geyser wire size guide.

The bathroom load is not the problem

Add up what a washroom actually draws with the geyser left out: a 40 W ceiling light, a 20 W mirror light and a 50 W exhaust fan is 110 W, which at 220 V is half an amp. The 1.5 mm² conductor feeding it is rated 19.5 A. Nothing on that circuit is anywhere near its limit, and no amount of thicker wire makes a bathroom safer.

What does make it safer is the earth, the RCD and where the accessories sit. Water lowers the resistance of everything, including a person, so a fault current that would be a nuisance in a bedroom is a serious shock in a shower. That is why the bathroom is the one room where the wiring decisions are about layout rather than about size.

Where things go in a wet room

Switches outside the door, or a ceiling pull-cord inside. A wall switch reachable from a wet floor is the arrangement to design out.
No socket outlet within reach of the bath or shower. If a socket is needed for a shaver or a hair dryer, put it on the dry side of the room, well clear of the splash area.
The geyser isolator outside the wet area — a double-pole switch that kills both live and neutral, so the heater can be isolated without anyone standing in the shower.
An IP-rated fitting for any light directly over the shower or bath. An open batten holder there collects steam.
Earth every point, and bond the metal. The geyser body and the metal pipework go back to the earth bar; size that bonding conductor with your electrician against the installation's earthing arrangement.
Switch the exhaust fan with the light where the fan is there for steam, and give it its own conduit drop so it can be replaced without opening the light circuit.

How far the bathroom can be from the board

This is the number that actually moves in a bathroom, because water heaters end up on roofs and at the far end of the house. 2.5 mm² drops 18 mV per amp per metre. Hold the installation to 3% of 220 V — 6.6 V — and give a final circuit about half of it, 3.3 V, since the run from the meter to the board has already spent the rest.

A 3000 W storage geyser at 13.6 A, 12 m from the board on 2.5 mm², drops 18 × 13.6 × 12 ÷ 1000 = 2.94 V — inside budget, and that budget runs out at about 13 m on this size. Move the same heater to a roof tank 25 m away and 2.5 mm² is at nearly double its share, so the run goes up a size or two.

Volts lost in the geyser circuit at 13.6 A — a 3000 W storage element at 220 V — against a final-circuit budget of 3.3 V, half of 3% of 220 V. Figure = mV/A/m × 13.6 A × run ÷ 1000; the run is one way, along the route the cable takes. Current capacity and voltage drop per BS 7671, reference method C (clipped direct), 30°C ambient; conductor data per IEC 60228. Verify sizing with a licensed electrician for your installation.
Run	2.5 mm²	4 mm²	6 mm²
10 m	2.45 V	1.50 V	0.99 V
12 m	2.94 V	1.80 V	1.19 V
15 m	3.67 V	2.24 V	1.49 V
20 m	4.90 V	2.99 V	1.99 V
25 m	6.12 V	3.74 V	2.48 V

Measure the route, not the room — down the wall, along the chase, up through the slab — and put your own length into the voltage drop calculator.

A bathroom is a wet area, and the rules that matter here are about placement and protection as much as conductor size. Have a licensed electrician confirm the accessory positions, the earthing and bonding, the RCD, and the cable size for your washroom before you buy — or start with the cable size calculator.

How much wire one bathroom takes

Five points and an earth run make a full washroom: a ceiling light, a mirror light, an exhaust fan, a socket on the dry side and a geyser point, with one earth conductor back to the board. Points times the average run back to the board, times the conductors each run carries.

Lights and fan: 3 × 10 m × 2.5 conductors = 75 m of 1.5 mm². Socket: 1 × 10 × 3 = 30 m of 2.5 mm². Storage geyser on a 12 m run: 1 × 12 × 3 = 36 m, so 66 m of 2.5 mm² in total. Add 15% for cutting waste and it is about 86 m of 1.5 mm² and 76 m of 2.5 mm². The 6 mm² earth is not a points calculation at all: it is a single cut length, about 8 m, run from the bathroom back to the earth bar — measure that route and cut to it.

A coil of house wire in Pakistan is 90 m, so read that result honestly: a bathroom is a cut-length job, not a coil job. Nobody buys wire one washroom at a time. Add these metres to the house list rather than ordering them alone — the method is on how much cable a house needs, and a worked plot total is on 5 marla house wiring. Two bathrooms on one plan roughly double the figures above.

Frequently asked

Bathroom ki wiring mein konsa wire lagta hai?

Lights aur exhaust fan ke liye 1.5 mm² (3/.029) 6 A MCB par. Socket ke liye 2.5 mm² (7/.029) 16 A par, magar socket paani wali jagah se door. Geyser ka apna alag circuit DB se aayega. Poore bathroom ko 30 mA RCD ke peeche rakhein aur har point ki earth zaroor lagayein.

What size wire for a geyser point in a bathroom?

It follows the element wattage on the plate. A 3000 W storage geyser draws 3000 ÷ 220 = 13.6 A and takes 2.5 mm² on a dedicated 16 A MCB; a 4500 W instant heater draws 20.5 A and takes 4 mm² on 25 A. The full ladder by wattage is on the geyser wire size guide.

Can I put a socket in the bathroom?

Keep it out of reach of the bath or shower. A shaver or hair-dryer socket belongs on the dry side of the room, clear of the splash area, on 2.5 mm² at 16 A and behind the same 30 mA RCD as the rest of the room. Many houses simply put that socket in the corridor outside the door instead, which is the easier answer.

Does a bathroom need an RCD?

Yes — a 30 mA residual current device, covering the bathroom circuits. Water lowers the resistance of a person to earth, so a fault that would trip nothing in a dry room can be a serious shock here. The RCD protects people, the MCB protects the cable, and neither replaces a proper earth at every point.

Bathroom mein switch kahan lagana chahiye?

Darwazay ke bahar, ya andar ceiling se pull-cord switch. Geela farsh par khare ho kar jo switch haath mein aa jaye, woh galat jagah par hai. Geyser ka double-pole isolator bhi wet area se bahar rakhein, taake heater band karne ke liye shower mein khara na hona pare.

Does the exhaust fan need its own wire?

Not its own circuit — a 30–60 W fan sits happily on the 1.5 mm² lighting circuit, and switching it with the light is the usual arrangement where it is there for steam. Give it its own conduit drop, though, so the fan can be replaced later without opening up the light circuit. Sizing for a larger unit is on the exhaust fan cable size guide.

How much wire for one bathroom?

About 86 m of 1.5 mm² and 76 m of 2.5 mm² with 15% wastage, plus a cut length of about 8 m of 6 mm² to the earth bar — from 5 points and an earth run, at a 10–12 m average run and 2.5 to 3 conductors per run. A coil is 90 m, so a bathroom is a cut length off the house order, not a purchase of its own.

The cable for this circuit

Two-core standard cable with black outer sheath, cut back to show red and black insulated stranded copper conductors

2.5MM² · 2 CORE · 450/750 V · CU CLASS 2

2.5mm 2 Core Standard Cable

Class 2 stranded copper, PVC insulated and sheathed, 450/750 V, drawn on the Pilone line in Lahore. Rated 27 A clipped direct at 30°C — the size this guide calls for on a socket and on a storage geyser point.

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Prices track the daily copper rate, so we quote per metre and per coil on WhatsApp. Send the whole house list and your city rather than one bathroom's cut lengths.

Wiring in conduit is pulled as single core: 3/.029 single core copper cable for the lights and fan, 7/.029 copper cable price for the socket and the storage geyser, 4mm single core copper cable for an instant geyser point, and 6mm single core copper cable for the earth run.

Bathroom cable, at the factory rate

We draw the copper in Lahore and sell it at the day's rate — no dealer margin. Send the full list and your city for today's number: Punjab in 1–2 days, rest of Pakistan in 2–4.

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