Interesting one that. As one on the outside looking in, so to speak, I would associate yellow flex cable with 110V purely because that is the only use I’ve ever seen them put to. The caravan I’m staying at the moment has a white cable with blue 240V CEE plug and trailing socket and I’ve noticed from looking around the site that the made-up ones tend to be orange or blue cables – not a yellow one seen yet.

Of course the 110V extension leads that are about to be used in South Oxfordshire chez Hutch will be orange with black or orange NEMA 5-15 plugs and sockets on them ‘coz that’s what I’ve got! [Linked Image]