Which wire is best for house wiring? A practical buyer’s guide

There is no single “best wire”: there are four decisions

Most people asking which wire is best for house wiring are really asking four separate questions at once. Separating them makes the answer straightforward, because three of the four have a settled answer for Indian homes and only one is genuinely a matter of preference.

Copper or aluminium for house wiring?

For circuits inside a home (lights, fans, sockets, geyser and air-conditioner points) the practical answer in India is copper. Copper carries more current for a given cross-section, so the conductor is physically smaller for the same duty, and it behaves better at the screw terminals inside switchboards and distribution boards, which is where domestic wiring problems usually start.

Aluminium conductors are normal on the supply side: service cables, incoming feeders and heavier distribution runs, where the saving on a long run is significant and the terminations are engineered for it. That is a different product from house wire and a different conversation with your contractor.

Every house wire record in our wires and cables catalogue is single-core annealed copper with PVC insulation, rated 1100 V. We do not list aluminium house wire, because for the circuits inside a flat there is no good reason to specify it.

Conductor size: the decision that is not yours to guess

Size is quoted in square millimetres of conductor cross-section: 0.75, 1.0, 1.5, 2.5, 4, 6 sq mm and upwards. It is decided by the design current of the circuit, the length of the run, how the cables are grouped and installed, and the rating of the MCB protecting them. A circuit schedule prepared by your electrician or consultant fixes these. A table on a website cannot.

What a table can usefully do is tell you which sizes to expect on that schedule, so you can sanity-check a quotation before you pay for it. These are the sizes that appear repeatedly on domestic circuit schedules in Delhi NCR:

What that means for the coils you order

A whole-flat rewire is normally three or four sizes bought together, not one. The 1.0 and 1.5 sq mm coils cover lighting, 2.5 sq mm covers the socket circuits, and one or two heavier sizes cover the geyser, air-conditioner and submain runs. Ordering all of it as a single requirement is also how you get sensible pricing, because it is quoted as one job rather than as a series of small purchases.

FR, FRLS and FR-LSH: what the insulation grade buys you

Every house wire has a PVC layer over the copper. The obvious job is electrical: PVC is a good insulator, so it keeps the conductor separated from whatever it touches. The less obvious jobs matter just as much: it protects the copper from moisture and abrasion while the wire is pulled through conduit, it is flexible enough to survive being drawn around bends, and its colour is how an electrician tells line from neutral from earth years later.

Plain PVC also burns, and it produces dense smoke and acidic gas when it does. That is what the grade letters address. They describe how the compound has been modified, and this is the one specification decision on this page where spending more genuinely buys something.

How to decide between them

• A ground-floor or low-rise home with straightforward escape routes: FR is the normal specification, and it is what most Delhi NCR domestic schedules are priced on.
• A flat in a high-rise, or anywhere the escape route is an internal corridor or a single staircase: the low-smoke grades are worth the difference, because smoke rather than flame is usually what stops people getting out.
• A commercial fit-out, hotel, school or healthcare space: check the project specification first. It will normally name the grade, and it may name the standard as well.
• Mixing grades across one flat to save money is a false economy. The cost gap on a domestic quantity is small next to the cost of pulling wire through conduit twice.

Our catalogue carries all three flame-retardant grade names above in copper house wire: Finolex FR and FRLS and Polycab FR-LSH. If you are not sure which grade your drawing calls for, send us the specification page and we will quote against it.

Which company’s wire is best?

This is the question most people start with, and it is the one with the least at stake, provided you buy a genuine, ISI-marked product from an authorised source. PVC-insulated cable for working voltages up to and including 1100 V is covered by IS 694, and ISI certification against it is mandatory for manufacturers. A wire carrying a valid ISI mark has been certified against the same conductor resistance, insulation thickness, high-voltage and flammability requirements regardless of whose name is on the drum.

So the honest comparison is not “which brand is safer”. It is which manufacturer gives you the grade, the size and the coil length you need at a price you can get quoted today. Those differ more than people expect:

A more useful way to choose

1. Start from the grade your specification or your own risk tolerance requires. If it calls for low smoke, the shortlist is already narrower.
2. Check that the manufacturer lists every size on your schedule. Buying one size from a second brand because the first is short of it is normal and harmless. There is no compatibility issue between brands.
3. Match coil length to the job. A single room does not need a 300 m coil, and a full rewire bought in 90 m coils means more joints and more offcuts.
4. Compare the price quoted for the whole list rather than the price of one coil. Coil lengths differ between sizes and between brands, so a coil-to-coil comparison is not comparing like with like.
5. Confirm the product is genuine before you accept delivery. See how to check a Finolex coil is genuine; the same principles apply to any brand.

Five expensive mistakes to avoid

1. Buying a size down to save money. The saving is a few thousand rupees on a flat; the cost is a circuit that runs warm for twenty years and cannot be upgraded without opening the walls again.
2. Quoting the whole flat on one size. A schedule that is 2.5 sq mm from the lights to the geyser is a sign nobody sized the circuits.
3. Treating “FR” and “FRLS” as interchangeable words. They are different products at different prices, and it is one of the easiest places for a quotation to quietly drop a grade.
4. Comparing coil prices instead of comparing requirements. A 90 m coil and a 300 m coil are not comparable line items.
5. Buying from whoever is cheapest with no invoice and no traceable source. This is the only mistake on the list that can put a counterfeit product inside a wall.