4 mm² Wire in Pakistan: Which Appliances Can It Safely Run?

A new AC, an electric geyser or a built-in oven usually comes with the same instruction from the electrician: “Is ke liye alag line dalni paregi.” That separate line is almost always 4 mm² wire, also known as 7/36. It is the size that lets one heavy appliance run at full power without heating the wiring or tripping the breaker.

This guide explains which appliances 4 mm² wire can safely run, which ones need a bigger or smaller size, and how to wire a dedicated appliance line correctly.

4 mm² (7/36) Wire at a Glance

Why Heavy Appliances Need Their Own 4 mm² Line

Ordinary socket circuits are wired in 2.5 mm² or 7/29 and shared by many sockets. That works for a TV, a laptop charger or a fan. A heavy appliance, however, draws a large current for hours, and an AC compressor pulls an extra surge every time it starts.

Putting that load on a shared socket circuit overheats the socket, the plug and the wire. A dedicated 4 mm² line from the DB, with its own breaker, carries the current comfortably and keeps the rest of the house unaffected.

Appliances 4 mm² Wire Can Safely Run

These are typical figures. Always check the rating plate of your appliance, and ask your electrician to confirm the wire and breaker.

When 4 mm² Is Not Enough

• Very long runs. If the AC outdoor unit or pump is far from the DB, voltage drop increases. Move up to 7/44 (6 mm²).
• Several heavy appliances on one line. Two ACs or an oven and a geyser together should not share one 4 mm² line. Give each its own circuit, or use 7/44 as a sub-main to a small board.
• Instant electric water heaters. Some draw 5 kW or more. Check the manual; they may need 6 mm².
• Main line. 4 mm² is not a main line wire. Use 7/52 or 7/64 for that.

When 4 mm² Is More Than You Need

• Lights and fans need only 1 mm² or 3/29.
• Normal sockets for TV, fridge, washing machine and charging need 2.5 mm² or 7/29.

How to Wire a Dedicated 4 mm² Appliance Line

1. Start from the DB. Give the appliance its own breaker in the distribution board.
2. Run phase, neutral and earth. Use 4 mm² for phase and neutral, and an earth wire as your electrician advises. Red, black and green make the line easy to identify.
3. Use a heavy-duty socket or isolator. A 15 A or 20 A socket, or a double pole isolator near the AC, is better than a normal 5 A socket.
4. Keep joints to a minimum. Run the wire in one piece from the DB to the appliance wherever possible.
5. Tighten every terminal. Loose terminals on heavy circuits are the most common cause of burnt sockets.

For AC-specific sizing by ton, see our AC wire size guide.

Why Choose Thrive Cables 4 mm² Wire

Thrive Cables makes 4 mm² (7/36) single core copper wire in Lahore with 99.9% pure copper and fire-retardant PVC insulation. Every coil has the full 7 strands at the right thickness, and it comes in 45 m and 90 m coils in 7 colours. Order at factory price on WhatsApp at +92 324 6570645.

Frequently Asked Questions About 4 mm² Wire

Is 4 mm² the same as 7/36 wire?

Yes. 7/36 has about 4.6 mm² of copper and is used as the 4 mm² class of wire in Pakistan.

How many amps can 4 mm² wire carry?

Roughly 30 to 32 A in conduit, depending on installation. Appliance circuits are usually protected by a 20 A to 25 A breaker.

Can I run two ACs on one 4 mm² line?

It is not recommended. Give each AC its own line and breaker so a fault on one does not affect the other.

Is 4 mm² enough for an electric geyser?

For most 2 to 3 kW geysers, yes. Instant heaters of 5 kW or more may need 6 mm².

Do I need 4 mm² for the fridge?

No. A fridge uses little power and works well on a normal 2.5 mm² socket circuit.

Conclusion

4 mm² (7/36) wire is the right size for one heavy appliance on its own line: an AC up to 2 ton, a geyser, an oven, a heater or a water pump. It carries roughly 30 A, handles starting surges and keeps the rest of the wiring cool. Use a bigger size for long runs or combined loads, a smaller one for lights and ordinary sockets, and have a qualified electrician confirm every heavy circuit.