What size wire does an AC need in Pakistan?

PILONE CABLES TECHNICAL TEAM

An AC point takes 2.5 mm² copper at 1 ton, 4 mm² at 1.5 and 2 ton, 6 mm² at 3 ton and 10 mm² at 4 ton, three-core with the earth the same size as the live, each on its own type C MCB — 16, 20, 25 and 32 A in that order. Those sizes assume a 220 V single-phase supply and cable clipped direct at 30°C; in conduit, bunched with other circuits, or on a long run from the board, take the next size up.

The circuit is the same shape at every tonnage: one cable from the distribution board, one breaker of its own, a double-pole isolator at the outdoor unit. What changes is the current — watts ÷ 220 V gives the running current, the breaker is picked above that, and the cable has to stay above the breaker after it is derated for conduit and summer heat.

AC wire size chart, by tonnage

Read the rating plate on the outdoor unit before you read this chart. It gives the maximum current for your exact model, and no chart beats it. Where the plate is gone or unreadable, these are the working figures for a 220 V single-phase house supply. The arithmetic is one division: 2000 W ÷ 220 V = 9.1 A for a 2 ton unit, 3600 W ÷ 220 V = 16.4 A for a 3 ton. The chart rounds those to the nearest amp.

One air conditioner per circuit on a 220 V single-phase supply. Wattages are typical for the tonnage — take your own from the rating plate. Copper, PVC, current capacity per BS 7671 reference method C (clipped direct) at 30°C ambient; 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.
Tonnage	Power, typical	Current at 220 V	MCB	Live and neutral	Earth	Trade code
1 ton	1000–1200 W	4.5–5.5 A	16 A type C	2.5 mm²	2.5 mm²	7/.029
1.5 ton	1500–1800 W	6.8–8.2 A	20 A type C	4 mm²	4 mm²	7/.036
2 ton	2000–2400 W	9–11 A	25 A type C	4 mm² to 25 m, then 6	same as live	7/.036
3 ton	3000–3600 W	14–16 A	25 A type C	6 mm²	6 mm²	7/.044
4 ton	4000–4800 W	18–22 A	32 A type C	10 mm²	10 mm²	7/.052

Two things in that chart are worth saying out loud. The earth is the same size as the live, which is what the third core is for — not a thinner strand tucked in beside it. And the breaker is a type C in every row, because a type B will nuisance-trip on the compressor inrush and the householder will blame the cable. 1.5 ton AC wiring is the point most Pakistani houses actually build, and its 4 mm² row is the one this chart gets argued about.

How to read your own unit off the chart

Four steps, in this order. Skip the first and the rest is guesswork.

1. Read the plate

The outdoor unit carries a rating plate with its maximum current and its LRA, the locked-rotor figure the start surge reaches. Those two numbers beat any tonnage chart, including this one.

2. Turn watts into amps

Watts ÷ 220 V. A 1.5 ton unit at 1800 W is 8.2 A. Pakistan is 220 V nominal, so charts worked at 230 or 240 V read low here — and when the supply sags in peak hours the same watts pull more amps, not fewer.

3. Pick the breaker above it

The MCB sits above the running current with room for the surge: 16 A, 20 A, 25 A or 32 A from the chart, type C, on a way of its own in the board.

4. Size the cable above the breaker

Not above the running current — above the breaker, after derating. Cable in conduit in a Lahore summer carries less than its table figure, and that reduced number is what has to clear the MCB.

Step four is the one the charts skip, and it is where most disagreements about AC wire size actually come from. Two shops quoting different sizes are usually assuming different installations, not different units. The derating arithmetic is worked in full on 1.5 ton AC wire size, where the margin decides between 2.5 and 4 mm².

The cable ladder behind the chart

Every size in the chart is read off this ladder. The trade code column is what you will actually be quoted at the counter: AC wires are sold in Pakistan by imperial strand code, standards work in mm², and the two do not land on each other exactly.

Copper, PVC, 450/750 V. Two loaded cores is the column for a single-phase AC point even on a three-core cable, because live and neutral are the only loaded conductors; three loaded cores is for three-phase. Capacity and voltage drop per BS 7671 reference method C (clipped direct), 30°C; strand data per IEC 60228. Trade codes are imperial diameters and are nominal, not exact equivalents. Verify sizing with a licensed electrician for your installation.
Size	2 loaded cores	3 loaded cores	Voltage drop	Class 2 strands	Trade code	On an AC circuit
1.5 mm²	19.5 A	17.5 A	29 mV/A/m	7/0.53	3/.029	Lights and fans only
2.5 mm²	27 A	24 A	18 mV/A/m	7/0.67	7/.029	1 ton
4 mm²	36 A	32 A	11 mV/A/m	7/0.85	7/.036	1.5 and 2 ton
6 mm²	46 A	41 A	7.3 mV/A/m	7/1.04	7/.044	3 ton, long 2 ton runs
10 mm²	63 A	57 A	4.4 mV/A/m	7/1.35	7/.052	4 ton
16 mm²	85 A	76 A	2.8 mV/A/m	7/1.70	7/.064	Submain feeding several points

1.5 mm² is on the ladder to be ruled out. At 19.5 A it sits below even a 20 A breaker before any derating, so on an AC circuit the cable would fail before the protection did. When two or three AC points go in at once, it is the last row that matters: the submain and the main switch become the limit long before the individual point cables do, so total the load before adding the way.

How far the AC can sit from the distribution board

Heat decides the size on short runs; length decides it on long ones. Voltage drop is the cable's own loss — millivolts per amp per metre, times the current, times the one-way run — and it is the reason the same tonnage takes a different size at the far corner of a plot than it does next to the board.

Longest one-way run each size reaches on a 3.3 V budget, which is half of the 3% of 220 V the whole installation is allowed — the submain from the meter has already spent the rest. Run = 3300 ÷ (mV/A/m × current), at the top of each tonnage's current band. A dash means the size is below the minimum this guide recommends for that circuit, whatever the length. Voltage drop per BS 7671 method C, 30°C, copper, PVC. Verify sizing with a licensed electrician for your installation.
Tonnage	2.5 mm²	4 mm²	6 mm²	10 mm²
1 ton, 5.5 A	33 m	55 m	82 m	136 m
1.5 ton, 8.2 A	—	37 m	55 m	91 m
2 ton, 11 A	—	27 m	41 m	68 m
3 ton, 16 A	—	—	28 m	47 m
4 ton, 22 A	—	—	—	34 m

Work one row yourself: a 2 ton unit at 11 A on 4 mm² drops 11 × 11 × 27 ÷ 1000 = 3.27 V over 27 m, which is the budget spent. That is why the 2 ton guide rounds the practical limit to 25 m and goes to 6 mm² beyond it. On a 4 ton, 6 mm² is a special case rather than a flat no — clipped in open air on a short run it can hold, and the 3 and 4 ton guide sets out when. For your own length and current, the voltage drop calculator does the sum.

The best wire for an AC: type, cores and metal

Size is half the question. The other half is which cable, and anyone asking for the best cable for an AC point is really asking three things at once.

Three core, not two. Live, neutral and earth in one sheath, all the same size, so the earth cannot be quietly undersized on site. Two core is for circuits where an earth conductor is already run separately. Four core is a three-phase cable and belongs on units fed at 400 V.
Standard or flexible, by where it sits. Class 2 stranded standard cable is the fixed run: board to isolator, chased or in conduit. Class 5 flexible is the short tail that has to bend around the condenser and the isolator without fighting you. Both are copper and both carry the same current at the same size — the difference is how many strands make up the conductor, 7/0.85 against 56/0.30 at 4 mm².
Copper, not aluminium, at these sizes. We draw aluminium cable and it earns its place on service drops and long feeders, where weight and cost per metre decide. On an AC final circuit at 2.5 to 10 mm², terminating into the small clamps inside an isolator, copper is the metal that belongs.

For the sizes in the chart that means 2.5mm 3 core flexible cable at 1 ton, 4mm 3 core standard cable at 1.5 and 2 ton, 6mm 3 core standard cable at 3 ton and 10mm 3 core standard cable at 4 ton. A split unit needs a second cable on top of that, between the indoor and outdoor halves, and its size comes from the unit manual rather than from any chart — that run has its own rules on the split AC interconnecting cable page.

AC ke liye kitne mm ka wire chahiye?

Tonnage par depend karta hai. 1 ton ke liye 2.5 mm² (trade code 7/.029) 16 A MCB par; 1.5 ton ke liye 4 mm² (7/.036) 20 A par; 2 ton ke liye bhi 4 mm², magar 25 meter se lamba run ho to 6 mm²; 3 ton ke liye 6 mm² (7/.044); 4 ton ke liye 10 mm² (7/.052). Har point ka apna alag MCB aur apni alag cable board se aani chahiye.

3-core lein, taake earth bhi live ke barabar ho. Aur pehle outdoor unit ki plate parhein — us par likha maximum current har chart se ziyada sahi hai.

Guides by AC size

1 TON

1 Ton AC Wire Size

2.5mm on a 16A MCB, and the run length that forces 4mm.

1.5 TON

1.5 Ton AC Wire Size

The 2.5-or-4 argument, settled with the derating sum.

2 TON

2 Ton AC Wire Size

Where 4mm runs out of margin and 6mm takes over.

3 AND 4 TON

3 Ton AC Wire Size

6mm at 3 ton, 10mm at 4 ton, and the isolator.

SPLIT

Split AC Interconnecting Cable

The second cable, indoor unit to outdoor unit.

INVERTER

Does an Inverter Change the Size?

Softer start, same conductor. Why it does not shrink.

Wiring the AC point, board to outdoor unit

One way in the distribution board, one MCB of its own, type C at the rating in the chart. Not a spur off a socket circuit.
Three-core cable from that MCB along the wall or conduit to a double-pole isolator mounted beside the outdoor unit, so a technician can kill the unit without walking back to the board.
A short tail from the isolator into the unit's terminal block. A plug joint on a hardwired split is a weak point that gets warm.
On a split, the interconnecting cable runs separately between the indoor and outdoor halves, sized to the unit manual, and it does not replace the supply cable.
Measure the route, not the room: down the wall, along the chase, out through the sleeve, up to the outdoor unit, plus a metre at each end.

Every AC point takes its own breaker and its own cable run — never shared with sockets or lighting. Current capacity depends on how the cable is installed, so derate for conduit, grouping and ambient above 30°C, and take the correction factors for your method from BS 7671. Have a licensed electrician confirm the circuit for your unit and layout, or start with the cable size calculator.

Frequently asked

What is the best wire for an AC point?

Three-core copper, sized above the breaker rather than above the running current, on the AC's own MCB. In practice that is 2.5 mm² for a 1 ton unit, 4 mm² for 1.5 and 2 ton, 6 mm² for 3 ton and 10 mm² for 4 ton, all on a type C breaker. Take the third core so the earth matches the live, and read the rating plate before trusting any chart.

What is the AC wiring cable size for a new house point?

Size it to the unit, not to the room. Watts divided by 220 V gives the running current, the MCB goes above that, and the cable has to clear the MCB after derating. For a 1.5 ton point that comes out at 4 mm² three-core on a 20 A type C MCB, run from the distribution board rather than spurred off a socket circuit.

Can an AC run on the existing room wiring?

No. Room socket circuits in most Pakistani houses are 2.5 mm² on a 16 A breaker, already carrying sockets and often lights. An AC added to that shares the cable and the breaker with everything else on it, so the breaker trips or the cable runs warm. Every AC point takes its own cable and its own MCB from the board. A window unit on a dedicated 16 A socket is the one qualified exception.

Why does an AC need a type C breaker and not a type B?

Because of the compressor inrush. A type B trips at a current low enough that the surge when the compressor starts crosses it, so the breaker drops out with nothing wrong on the circuit. A type C has a higher instantaneous threshold: it rides through the start and still opens on a fault. Every row of the chart is type C. When a B curve nuisance-trips, the householder blames the cable, and the cable is not the fault.

How far can an AC be from the distribution board?

On a 3.3 V drop budget, 4 mm² reaches about 37 m at a 1.5 ton unit's 8.2 A and about 27 m at a 2 ton unit's 11 A; 6 mm² reaches 55 m and 41 m on the same two currents. Past those lengths go one size up.

Can one cable feed two AC points?

No. Each AC point takes its own cable and its own MCB from the distribution board, so two units never share a run. What does need checking when a second or third point goes in is the level above: the submain feeding the board and the main switch become the limit long before the individual point cables do. Total the load of everything on that board before you add the way.

Cable for AC wiring, at the factory rate

Send the tonnage, the metres from the board to the outdoor unit and your city. We draw the copper in Lahore and quote the day's rate — Punjab in 1–2 days, rest of Pakistan in 2–4.

WhatsApp about AC cable