SouthernAtHeart:
be80be:
You have to clear all the copper over your mains to if using a double side board...so the board isn't enough of an insulator for 220VAC?
The board is not as thick as the minimum gap so yes you have to do it. It is also capable of coupling high voltages into the ground plane as it acts as a capacitor.
The slots used in PCBs are to get stuff closer. The rules on air gaps are different from the rules on PCB spacingq.