Coils in, metres out
A coil is a fixed length and customers buy cut lengths, so the conversion has to live on the item or the stock figure means nothing within a month. Selling in metres against stock held in the same unit keeps it honest, and the gap that shows up over time is real loss — offcuts, short measures, wire taken and not billed — rather than a rounding error.
Size, core and brand
A 1.0, a 1.5 and a 2.5 are different products, as are single core and multi core and each brand. Customers ask by size and brand together, and entering them generically guarantees both wrong rates and a useless stock figure. Each combination as its own item is what lets the counter answer quickly and the reorder list read as a list.
Fittings alongside the wire
Most wire shops also carry switches, sockets, MCBs, boxes and holders — thousands of small lines in several brands. Barcoding the fast movers keeps the counter quick while the wire itself is billed by name and length. Both on the same invoice, each with its own unit, is the ordinary sale here.
Electrician accounts
Your regular buyer draws wire and fittings through a wiring job and settles at the end. Many small visits over several weeks, which is exactly how an account grows unnoticed. A credit limit stops a stalled job continuing to draw, and a monthly statement settles the account while the work is fresh for both sides.