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Fuse block, breaker recommendations

EFI Wiring Fundamentals

Discussion and questions related to the course EFI Wiring Fundamentals


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Hey guys, any preference for fuse block, breakers, kill switches? Both the style of block, and kill switch, thoughts on circuit breakers and possibly some budget options for all of the above? I don't know if this is already covered in the list of suppliers or a future wiring course but they seem to be integral to completing a first harness. I know kill switches were mentioned briefly.

My biggest concern is fuse blocks/aka power distribution blocks which feel like a potential source of failure from a driver's point of view (many attachment points, crimps). I'm wondering if there aren't better intermediate options for the budget racer with the solid state, fuse less PDM systems taking over the high end market already. Cartek has a basic 4 channel relay+fuse panel for example @ around 210 USD, though other more expensive options come with way more features. Maybe you guys have personal preference on how to set any of these options up with current technology while balancing the cost.

I'm talking about for a heavily modified car or engine/chassis swaps. I've got some pretty 'fancy' looking fuse blocks on one of my cars that could use replacing now. These things rattle around in their own housings... it's awesome. They were also terminated into the glove box so tight there was no slack to work at all, so I had to label and replace everything just to get the wiring out of there and mount it in a serviceable location. It was fun getting in there with the cage and sadly I only wanted to remove the dashboard to add a dash bar!

On a side note - while I have time + available neurons. I don't think you guys included info on main power or ground wiring size, preferred style, terminating large wire ends etc. in the current wiring course. I'm referring to custom wiring or even just battery relocation which is pretty much standard even for hard parking. The cars come with power and ground circuits, but they're overloaded with all of our gadgets at some point as well. Just my .02c after going through the course.

I am a big fan of the Bussman RTMR series of fuse/relay blocks. They are very compact, you crimp wires directly to the terminal that recieves the fuse/relay, have a sealed cavity plug/silicone seal system and are pretty robust for general light duty circuits. The only thing is they take iso280 relays. Which are fine, they just have a different base than standard. I dont like to use them for heavier circuits though. (Fuel pumps or thermo fans etc.) They are used in earth moving like in Bobcat and Cat in certain applications. They seam ok except for higher load applications, or where alot of muck/grime/moisture can ruin things.

For slightly heavier circuits like thermo fans or main relay I like to use something like a more conventional mini relay / relay base.

For even heavier circuits like large fuel pump/s, then i use 75a bosch main current relays. These have bolt down terminals for a very secure and dependable connection. (When you start pushing higher currents, wedge in type terminals dont work well, you realy need to use something that is a screw down connection.)

For heavier circuits above about 15a of continuos load, then i like to use Midi fuse.

And if i relocate a battery, and have a long or potentially risky cable run, then I will use a mega fuse, and sometimes a large solenoid so the circuit is only active during cranking. And smaller fused runs to the rest of the vehicle electrics.

For isolators, i ended up getting about 20+ new isolators from a bunch atlas copco machines that were being spec'd up. So brand new OEM isolators removed, and had isolators with lockable lock outs fitted. So i have been using them for a while now. They are quite nice, duel circuit, robust, PA66 GF reinforced body. Have nickel or silver plated terminals, and they can take massive current because of the size of the engine in the machines they were fitted too.

For wire size. I use 2g for most battery to starter cable runs. And use 6g or 8g to power distribution / fuse blocks.

No specific recommendations, 'cept sitting down with a large sheet of paper (old school), or one of the free programs you can download, and figuring out ALL the circuits you're going to need and their amperages, then figure out wire guages, feed and ground details, which circuits can be swithed and which require relays, etc.