russelcrowe_:
So, out of curiosity... If you are certifying a product for 220 V, do you have to go to test them to 1600 V?! Thanks, I will.
No; however, if you want to be on the safe side and adjust your design for 1600vac, simply increase the minimum distance to 7.2mm of separation. As Paul alluded to earlier, the spacing applies to all connections, traces, and relay contacts.