Which one is the one you have showing?
And do you know if anyone sells a block that has equal slots for fuse/relay? Meaning 6 relays/6 fuses or 10 relays/10 fuses.
I'm using the 15303-5-2-4, coopers pdf breaks down the part numbering scheme
http://www1.cooperbussmann.com/library/news/RTMR.PDF
HAHAHAHAHA...well, Winch, E-fan, 4 sets of lights, converter, OBA(2)...that's 9 right off the bat. Basically, anything that I add an aftermatket switch for I'd want a relay to go with it. All electrical item I add will be running of a second battery so I can leave the truck one alone.
A winch is not going to need relays unless you plan to hardwire the controls, a normal relay will not handle the amp draw of a winch. It goes straight to the battery, and if you want an on/off you would use a high amp solenoid switch. If your talking a power inverter, i'd wire it like an aftermarket audio amp using a large blade fuse straight off the battery, don't see the need for a switch here so no need for a relay, though you could use a circuit breaker instead of the fuse if you want to be able to kill power to it. OBA, might be pushing it, you'd have to see what the compressor is pulling amp wise, I prewired my 3rd relay for OBA, but I have to make sure the compressor and my 12ga power wire will work ok, but I think I might just use a solenoid switch on some 10 gauge wire. Efans, personally I would just mount the relays on the fan shroud, its going to be right next to the battery, keep your wiring run short and simple. Heck 4 sets of lights is pretty much going to be a box by itself. Cooper rates the bused fuse stud for 100amps total power handling, so make sure the total of everything you might run at once isn't going to exceed that.
Power to the relays in the box, its just a little jumper loop from the fuse side. Since its bussed you only have to run one wire from the fuse, if your using a relay just jumper it over the right pin for the power input on the relay. On my pic, the little blue fuse is for my CB and has no relay, it just goes straight from the fuse to the cb.
Keep in mind with the rtmr, your not just buying the ~$20 box, you have to buy metripack 280 series female pins for each gauge wire you want to use (i used 12 and 16 IIRC), metricpack weather seals for each gauge (little booties that go on with the pins) and then the plugs for all the unused holes. Your also going to need a crimper, I just bought the cheapest $20-30 one and it worked great though. I got all that stuff from delcity (and the wire) because they have better prices with no minimums (ie having to order 500 pins when you will use 20). You crimp each pin for each wire and stick it in the back of the box, the pins are what the relay and fuses will plug into
