Wire Size Calculator: 1.5, 2.5, 4 or 6 sq mm for Home Wiring?
Free tool · Updated October 2, 2026 · By CouponTalk
Your result
Enter your measurements to see your result.
Quick answer
Current (amps) = load in watts ÷ 230 V. For PVC-insulated copper house wire in conduit, a common guide is 1.5 sq mm for lighting and fan circuits (10 A MCB), 2.5 sq mm for plug points (16 A), 4 sq mm for ACs and geysers (20–25 A) and 6 sq mm for main lines (32 A). A 1.5 ton AC drawing about 2,000 W needs roughly 9 A, so a 4 sq mm wire on a 20 A MCB is typical. Always have wiring done by a licensed electrician.
How to use this calculator
- Add up the watts of everything on one circuit.
- Measure the cable run from the distribution board.
- Use the result as a guide and confirm with a licensed electrician.
Reference table
| Circuit | Copper wire (PVC, in conduit) | Typical MCB |
|---|---|---|
| Lighting / fan circuit | 1.5 sq mm | 10 A MCB |
| Plug points (5–16 A sockets) | 2.5 sq mm | 16 A MCB |
| AC / geyser / heavy appliance | 4 sq mm | 20 A MCB |
| Main line / large AC | 6 sq mm | 32 A MCB |
These are typical figures for Indian homes. Check the product spec sheet, and ask an electrician or installer before you buy or fit anything.
Frequently asked questions
Which wire is used for AC in India?
A 4 sq mm copper wire on a 20–25 A MCB is commonly used for 1.5–2 ton split ACs, with a dedicated circuit.
Is 1.5 sq mm wire enough for plug points?
Not for heavy appliances. 1.5 sq mm suits lights and fans; use 2.5 sq mm for regular plug points and 4 sq mm for 16 A heavy sockets.
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