I think it would be safer to use a relay to do the actual switching. So the uC pin would drive the transistor ON/OFF, the transistor would drive the relay open/close, and the freewheeling diode is connected across the relay. A relay design would be pretty mush the sme for 110V or 240V. Use optoisolators (but of course).

But my knowledge of power electronics is limited to my experience in a heavy industry environment. Maybe you could use solid-state devices such as IGBTs and MOSFETs, but they are usually used in fast-switching applications. :-/ I have no clear idea what device to use in this case or how. You'll also have to deal with heating issues.

Also you don't know the importance of point #2) until you've received a few zaps :-)) I'd work in rubber slippers if I were you!

What are you using the RS-232 for?

Kunal (I know what you feel like) Kandekar