how do i wire a double insulated downlighter to an earthed supply
my instructions state i should make sure light is not connected to the earth ,and make sure my earth cables are connected to each other, but i only have one earth wire
Just wire the fitting to Switched Live & Neutral, making sure the earth wire is not in contact with the fitting(use green/yellow sleeving). The reason they say make sure your earth wires are connected together is to ensure earth continuity throughout the circuit, but if there is only one, it has nothing else to connect to.
When wiring ES (Edison Screw) light fittings, make sure the live conductor always connects to the centre pin of the lampholder, and the neutral to the side contact.