How Do Copper Price and Quantity Affect Cable Price?

How much of a cable price is copper or aluminium?

Conductor metal is a major part of cable cost, and larger conductors and multicore cables use more copper or aluminium. Copper has a density of 8.89 g/cm³ (material density basis), so one square millimetre of copper conductor weighs about 8.89 kg per kilometre. Aluminium, at 2.70 g/cm³ (material density basis), weighs about 2.70 kg per kilometre for each square millimetre. Multiplying these values by the conductor cross-section and the length gives an estimate of conductor weight, which is a useful first check when comparing metal content.

Conductor class also affects the electrical performance and the geometry of the cable. Under IEC 60228, plain copper classes 1 and 2 have a maximum DC resistance at 20 °C of 7.41 Ω/km for 2.5 mm², 1.15 Ω/km for 16 mm² and 0.193 Ω/km for 95 mm². Tinned or metal-coated conductors have slightly higher limits. A conductor that is close to its maximum resistance limit may contain less metal than one well below it, so ask for the stated resistance in every quotation. For more detail, see conductor classes and stranding.

Which cost drivers change a cable quotation?

Metal is only one line in the quotation. The table shows how each common cost driver affects the price and what to ask for when comparing offers.

The table lists cost drivers only. Do not compare offers until each driver has been confirmed in writing.

Insulation thickness, individual screens, braids, metallic tapes, armour, water blocking and special sheaths all add material and process stages. Certified or special compounds may have minimum order quantities, so ask the supplier for them before comparing prices.

Short runs create more setup and scrap per metre, so the price per metre rises when the order is small. Numerous custom drum lengths also increase handling. Drums should be handled and stored upright, never on a flange. Lift them with a mandrel through the centre hole or with forks under both flanges, not on the lagging, and keep all cable ends sealed. For drum handling guidance, see the drum packing and shipping article.

How does a copper price change affect the quote?

A quotation should state a metal-price basis and a validity date. Ask which copper price reference the supplier uses, when the price is fixed, and whether the metal adjustment is shown as a separate line. This lets you see how the metal part of the price moves and compare it with the conversion cost, which covers manufacturing, testing, packing and freight.

• Record the quotation date and its validity period.
• Separate the metal adjustment from the conversion cost.
• Ask what happens to the price if the metal basis changes before shipment.

Quantity works alongside the metal price. A larger, well-planned order usually spreads setup and testing over more metres, while a small order carries those costs on fewer metres.

How should quotations be compared on the same basis?

Compare offers only after they describe the same product and scope. Use this checklist before comparing prices.

1. Same conductor material and maximum resistance.
2. Same nominal size and length tolerance.
3. Same insulation, sheath, shield and armour.
4. Same standard and test list.
5. Same drum and delivery term.
6. Same quotation validity date.

Convert every offer to the same delivered net length, drum scope, metal basis and Incoterm. A price per metre is misleading if one quotation excludes drums or allows a different length tolerance. Confirm the net length rather than the number of packages, because a drum count does not show how much cable is supplied.

Why can an unusually low quote cost more later?

An unusually low quote should be checked for conductor resistance, material thickness, length and omitted scope. A cheaper offer may use a conductor close to its resistance limit, thinner insulation or sheath, a shorter length, or no drums or freight. Ask for the datasheet and the test scope before accepting a lower price, and make sure the supplier confirms the same items as the other offers.

Frequently asked questions