Copper vs aluminium wires for a shop or factory: what to specify

Wiring is one of those purchases nobody sees once the walls are closed — which is exactly why it deserves care. A wrong size or a poor-quality wire can mean tripping, heating and, in the worst case, a fire. The first question buyers usually ask is copper or aluminium, but the size, insulation and certification matter just as much.

Copper or aluminium — what is the real difference?

Both carry current; they behave differently.

• Copper conducts better, so a thinner copper wire carries the same current as a thicker aluminium one. It is also more flexible and forms more reliable joints. That is why house wiring inside shops, offices and homes is usually copper.
• Aluminium is lighter and costs less for the same current-carrying capacity, which is why it is common in larger power cables, service lines and long runs where weight and cost add up.
• Joints are where aluminium needs care. Aluminium-to-copper connections need the right lugs and connectors; a poor joint can loosen and heat up over time.

If you are unsure, tell the supplier or your electrician exactly where the wire will be used and let them recommend. Do not choose on price alone.

Getting the size right

Wire size is given as the cross-section in square millimetres (sq mm).

• Lighting circuits, power sockets and heavy loads such as air conditioners or machines need different sizes.
• The length of the run matters too: long runs may need a larger size to avoid voltage drop.
• Ask your electrician for a load calculation, or share the connected load with the supplier so they can suggest sizes.

Undersized wire is a false economy. The saving is small; the risk is not.

Insulation and type of cable

Ask what insulation and construction the wire has.

• PVC-insulated house wires are standard for internal wiring.
• FR (flame-retardant) and FRLS (flame-retardant, low-smoke) variants are often specified for commercial buildings, where smoke in a fire is a serious hazard.
• Armoured cables are used where the cable runs underground or is exposed to mechanical damage.
• Multi-core flexible cables suit machines and equipment that move or vibrate.

Certification and genuine material

• Ask whether the wires carry the ISI mark / BIS certification for the relevant standard.
• Check the printing on the wire itself — manufacturer name, size and standard are usually marked along its length.
• For large orders, ask for a test certificate for the batch.

Counterfeit and under-gauge wire does exist in the market. Buying from established suppliers and checking the markings protects you.

Coils, drums and quantities

House wires are commonly sold in coils of a fixed length, and larger cables on drums or cut to length. Ask:

1. The length per coil and whether part coils or cut lengths are available.
2. Whether the price is per coil, per metre or per kilogram.
3. Delivery charges for drums, which are heavy.

What to include in your enquiry

• Copper or aluminium (or ask for a recommendation)
• Size in sq mm, number of cores and insulation type (PVC, FR, FRLS, armoured)
• Total length or number of coils per size
• Brand preference, if any, and whether BIS certification is required
• Delivery location and date, and whether you need GST invoices

Browse suppliers in cables and wires, or post your requirement with the sizes and lengths you need.