I'm not sure that I understand the question. Are you looking for a device (often associated with motor overload protection) That is to turn your power on/off when you yourself demand it. To perform a relay function?
Well it's a big load for a relay, but not totally unheard of.
The next step up is a contactor.
Look up starter relays. The item that makes your car key turn on a motor of similar proportions. More of a classic car item these days, but a did a search and lots came up around a tenner
If it's not for overload and just for switching/isolating and you are handy with minor electronics/soldering some components together, this is small and light and pre charges as well
http://endless-sphere.com/forums/viewtopic.php?f=3&t=40142&start=300