Bare copper from substation and plant ground grids.

The mesh itself is only part of a grid lot. There are ground rods, rod couplings, exothermic weld connections, test wells, bonding jumpers to fences and structures, and copper braid at equipment connections that flex. Each of those is a separate item in the review, and each has its own condition question.

Size is the first thing a buyer confirms, because 2/0 and 4/0 look similar in a coil and behave very differently. Measure the strand count and the overall diameter, or read the print if a factory tag survived. A coil with no tag and no measurement is guessed at, and guesses do not help either side.

A grid is rarely lifted whole, and a utility decommissioning rarely leaves one intact. It is excavated in sections, cut either side of the welds and rolled into coils or bundles, and what arrives at the gate is a mix of long runs, short tails and rods with the weld still attached. That mix is normal and it is reviewed piece by piece.

Tails under a few feet are copper, not conductor. They are weighed rather than measured, and they are separated from pieces long enough to serve again as a bonding jumper or a short grid run. Sorting them before the visit is the single most useful thing a seller can do.

An exothermic weld is a permanent connection, so it comes out of the ground attached to whatever it joined. Cutting close to the weld leaves a short, hard stub that is awkward to coil, and cutting back a hand's length leaves clean conductor. Rods with a weld at the top are reviewed with the weld, since the rod is usually the lesser part.

Small fittings are the easiest thing to lose and the hardest to replace. Clamps, connectors, rod couplings and braid jumpers should travel with the lot in a box, labelled with where they came from. A box of fittings listed separately is reviewed on its own, and it often decides whether a short tail can be used again.

• Keep welded assemblies together instead of cutting the weld out.
• Note any rod that came out bent or heavily corroded.
• Separate clean bare copper from soil-caked or badly oxidised conductor.
• Bag small fittings and clamps rather than losing them in the coil.

Grid work is documented. There are as-built drawings, a test record from commissioning and often a later test after an extension. Those documents describe the layout and the resistance achieved, and they show the lot came from a maintained system rather than from a scrap pile behind a shed.

Handling is straightforward but heavy. Coils of 4/0 are dense, they do not stack well and they will damage a pallet. Say whether a forklift or a crane is available, and keep soil and gravel out of the coils so the weight is honest and the copper is not carrying the yard.

Bare copper is also bought outside grid work. The bare copper file covers coils, bar and offcuts from other sources.