A simple switch with Com, L1 and L2 is arranged to connect Com to L1 when the switch is in one position and Com to L2 in the other position.
The usual arrangement is to place the permanent live wire in the Com terminal hole and its associated Black wire in either L1 or L2 - it doesn't really matter which.
The Black wire sometimes confuses people because it looks like a neutral conductor - it isn't it's Switched Live - used to turn the light on and off - it should ideally have a red or brown sleeve on it at each end as a safety warning.
Lord Finchley tried to mend the Electric Light
Himself. It struck him dead: And serve him right!
It is the business of the wealthy man
To give employment to the artisian.
Take care...
Peccavi
January 2010