wire color should be brighter than red like pipes

[atomic1fire]

It would be cool if there was just a plastics analogue (like glass is a thing and metal is a thing)

You could just make wires with customized coating. For instance wires could get so hot they set on fire automatically because they were infused with welding fluid.

Rods + coating agent = wire

Coating agent being specific reagents that could cover a wire.