I'm looking at 2 wires from different suppliers each supposedly to the same specification but with different amperage ratings. Can anyone explain why they should have a substantial difference in the amperage they can handle. Also when it comes to PSUs how is the current rating for each wire calculated. With a PSU that can deliver, say 50A, is it the amps divided by the number of cables supplying power or something more complicated than that. I've been doing a fair bit of reading and haven't been able to come to any conclusions. Wire -1 AWG 18 24/0.2mm (0,75²) tinned copper conductor Overall diameter 2.3mm Rating 1000V 4.5A at 70°C DEFT61-12 (part 6) approved Wire – 2 24/0.2mm copper (Nom. conductor area: 0.75mm²) - Stranded core, single Overall diameter: 2.05mm Maximum current: 6A DEF61-12 (Part 6) Type 2 and BS4808 Part 2 A flexible wire for general purpose extra heavy duty interconnections within apparatus.