What is an RCP protected circuit?

whatever it is keeps tripping and knocking out some of the power in my house (seems to be all downstairs sockets & the heating).

is it a dodgy fuse somewhere? Or is the whole circuitry in need of a checkup?

Also, just found out my housemate turned on the emersion heater. about a week ago. He can fuck right off if he thinks i'm paying more than 5% of the bills.