I have a 2 gang switch in the kitchen.1 switch 2 way operates the ceiling light from 2 door ways no probs.The other 1 way switch operates the under cabinet lighting which when i switch on turns the lights on but then when i turn them off trips the rcd and a spark comes from the switch.I have 2 reds into the top and bottom of the connector and a live feed going to the 2 way switch.All the black wires are together in a choc block,help please