There is a whole range of American designations which are completely different from those used in the U.K. and Europe.

SPT-1 and SPT-2 are flat "zip-cord" or "figure-8" power cords, for example. You'll see SO, SJT, and SVT used to refer to some other jacketed power cords in thermoplastic or rubber.

THHN or THWN are PVC-insulated wires such as are commonly drawn through conduit.

Somewhere, I have a list of how to decode all the letters, but I can't lay my hands on it at the moment. One of our American friends might be able to oblige...... [Linked Image]