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House Wiring Wire-Size Guide: Which Finolex Gauge for Each Room

Electricians running conduit and wiring through a house under construction in Bangalore

One of the first questions every home builder faces is: which wire size do I need? Indian house wires are sold by cross-sectional area in square millimetres (sq mm), and using the right gauge keeps your home safe and your bills low. Here's a simple, practical guide.

What the sq mm number means

The bigger the sq mm, the more current the wire can safely carry. Under-sizing a wire causes heating and is a fire risk; over-sizing wastes money. Match the gauge to the load.

Room-by-room wire size guide

  • 0.75 – 1.0 sq mm — lighting circuits, bulbs, tube lights and ceiling points.
  • 1.0 – 1.5 sq mm — fan points and general 5A lighting/utility circuits.
  • 2.5 sq mm — 6A/16A power sockets, fridge, TV, washing machine, kitchen points.
  • 4.0 sq mm — air-conditioners, geysers and other high-load 16A appliances.
  • 6.0 sq mm — sub-mains, heavy kitchen loads and longer runs.
  • 10 sq mm and above — main incoming line and meter-to-DB connections (consult your electrician).

How many coils will a home need?

Finolex wires come in 90-metre, 180-metre and 300-metre coils. As a rough starting point, a 2BHK often needs several 90M coils across the common gauges, while a 3BHK or duplex needs more. The exact count depends on your floor plan and number of points — the easiest way is to share your wiring list with us for a precise material estimate.

Don't forget FR vs FR-LSH

For most homes, Finolex FR (flame-retardant) is the standard choice. If you want lower smoke and halogen emission in case of fire — recommended for bedrooms, kids' rooms and enclosed spaces — choose Finolex FR-LSH or Finolex Ultra. Read our FR vs FR-LSH vs Ultra comparison to decide.

Not sure what to order? Upload your wiring list and we'll prepare a complete, correctly-sized Finolex quote — delivered to your site by the next day.

Frequently asked questions

What wire size should be used for lights and fans?
1.0 or 1.5 sq mm is standard for light and fan circuits, protected by a 6A Curve B MCB. Use 1.5 sq mm where runs are long or where a circuit carries a large number of points, because voltage drop over distance rather than current is usually what governs.
Which wire size is needed for power sockets?
2.5 sq mm for 16A power sockets and kitchen circuits, with a 16A Curve C MCB. Ordinary 6A socket points can run on 1.5 sq mm, but anything intended for a fridge, microwave or washing machine should be on 2.5 sq mm from the start.
What size wire for an air conditioner or geyser?
4.0 sq mm on a dedicated circuit for a 1.5 ton air conditioner or a 3000W geyser, with a 20A Curve C MCB. A 1 ton unit or a 2000W geyser can use 2.5 sq mm on a short run. Long runs need checking for voltage drop, which can push the requirement up a size.
Can I use a smaller wire to save money?
It is the most expensive saving in a house. An undersized concealed circuit runs warm every summer, ages its insulation prematurely, and can only be corrected by breaking finished walls. The difference between correct and undersized on a whole house is usually a few thousand rupees.
How do I check the right size for my own circuits?
Use the free wire size calculator, which takes the load, the run length and the supply type, sizes the cable on current capacity and then re-checks it against voltage drop. It also suggests the matching MCB rating.

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