Series light chains were the mainstay of British fairy lights for many years, usually twenty 12-volt lamps for use on our 240V supply.
These would be connected to whatever plug was needed, which in modern times may well be the BS1363 13A fused plug.
I have a lot of these chains fitted with the less bulky 2-pin 5A round-pin plugs, used with suitable adapter leads.
Some modern sets use electronic flashers and sequencers, and these are generally parallel low-voltage run with the same sort of molded double-insulated cord and p;lug as you would find on any other modern appliance.
