1SlowSi

So I have my 75amp relay wired in for both my Walbro and Bosch 044 pumps. I have a 10ga coming from the battery to the relay and 10ga to both pumps. Rather than using 1 inline fuse near the battery, I have 1 inline 30amp fuse going to each pump so each circuit to a fuel pump has its own relay. Is this okay to do or do I still need to have a fuse near the battery?

My theory was either having one fuse for the entire circuit, or 2 fuses for each fuel pump circuit. Hell, maybe I'll run a 30amp fuse for each power wire for a total of 3 lol.

D1sclaimer

You're supposed to have one within a couple feet of the battery. It could still ground out in between the battery and your current fuses. Heres how I wired mine in.

I bought a 10 dollar MAXI fuse holder from the Walmart stereo section. I wired that into my 10 gauge wire and hid it underneath the battery tray after taking it out with the 3 bolts, there is just barely enough space to hide the MAXI fuse holder. It comes with a 40amp and 80amp MAXI fuse and I am using the 40amp fuse with no issues and my dual walbros.

1SlowSi

So just 1 main fuse for both pumps? Most people wire a single 30amp fuse for one walbro so I assumed that for 2 pumps I should double the fuses.

Right now I have only 1 inline fuse going to the bosch pump from the 75amp relay. I was going to run another inline from the Walbro/Relay but maybe Ill just run an inline fuse at the battery and leave the Walbro running without one.

SgtB

The fuse is for the weakest link which is usually the cable. You don't double the fuse with the load. The 10 gauge cable can handle 30 amps @ 12v at a length of 15 feet., so you put a 30amp fuse to prevent it from catching on fire. One fuse at the battery will protect everything in the line. If you want to add more insurance you can take an amp reading of the circuit at full load, and put the next highest fuse that doesn't exceed 30 amps. That way the fuse will trip sooner if a fault occurs.

EDIT: Found a better amp chart. Adjusted values.

1SlowSi

Okay so a single 30amp fuse at the battery is all I need for the entire fuel system?

SgtB

Yep.

1SlowSi

With what you said, I have to add that my bosch pump is in the engine bay so thats a long power wire from the trunk. Does this pump need an inline fuse? and if so, near the pump or near the relay?

EngineerX

If the Bosch pump is in the engine bay, I would think a separate 10g wiring from Bosch pump to battery would be best. Wire the in-tank pump separately.

** You can just have one wire from battery then split 2 wires, one to in-tank and one to in-engine bay

Use a fuse @ 6 - 8" from battery connection

Battery.....fuse.....split.... #30 relay terminal / #87....... Bosch pump
___________________.... #30 relay terminal / #87....... in-tank pump