Thanks for the reply, "Most relays have a Low voltage equiv, can you just swap it ?", now why didn't I think of that, obviously the simplest answer, just found one on farnell, I obviously need more coffee this morning!The cheapest way would be to use a 5V, 6V or 12V Relay to switch the 240V.
( you will need a transistor )
Most relays have a Low voltage equiv, can you just swap it ?
If the relay is a Motor Start type, they can have a 12V-AC or 24V-AC
and sometimes DC equiv replacement.
Whats your App ?
Yes, I have a couple of those I thought about using, I do prefer them, but in this situation there is not enough space for the heatsink in the prescribed enclosure.I future cases where you do have to switch high voltage AC and can't or don't want to use a relay I would suggest looking at optical isolated solid state switches.
They bring a safety factor (typically 3kv isolation between input and output terminals) that is very desirable. They typically turn on with a 3vdc or higher signal and use an internal triac to do the actual AC voltage switching. Some have zero crossing turn on feature. You do have to be aware of their heat sink requirement depending on the AC load current you plan on switching. They come is many sizes depending on current ratings and are cost competitive with electro mechanical relays.