500W at 230v takes about 2.2A so fit a 3A fuse in the plug
Two of them will draw just under 4.4A - perfectly OK on a ring main circuit.
If you're in the US then the current will be double.
Watts divided by Volts = Current in Amps
As a personal plea to you - try to have the light just in your own property and not shining into your neighbour's bedroom windows.
Peccavi, September 2009