Originally Posted by Jim Galbally
if you've got a relay with a fuse in it, does this mean you dont have to bother putting a fuse in the +ve feed
I think the relay fuses the main heavy load circuit only, so no u wouldnt need to fuse that circuit.
Originally Posted by Jim Galbally
and if the circuit normally has a 20amp fuse in it, does this mean im gonna want to use a 20amp relay? will using a 30/40amp relay still be fine (and can i use a 20amp fuse in a 30amp relay)
yes the relay needs to be able to cope with the heavy load circuit, so it needs to at least match the fuse u would be using, u could use a 20amp fuse in a 30 amp relay, but not the otherway round.
Originally Posted by Jim Galbally
oh, one more thing if i'm feeding the switch part of the relay from a physical switch, do i just wire the switch so that it has +12v on one end, and the other end goes to the relay activator thing... i dont earth the switch or anything stupid do it.)
Thats correct, unless the switch has a light or LED to indicate its staus, then u will need to earth the switch too to make it light.