Fuse size

old guy rich

old guy rich

Senior Member
Hey guys, what is the amperage of the fuses that are used by the folks running electric 6 volt fuel pumps ? No information about what fuses to use came with the pump. The pump is a E8092 Airtex. Thanks. old guy.
 
I just Rewired mine with a relay to battery side of solinoid. Used a 30 amp fuse.

Same fuel pump as yours. Btw I think you have a typo it's a 8902:)
 
I installed an Airtex E8902 on my 6v 36 coupe with a 10 amp fuse as recommended in the instructions. I only use the pump before starting engine. Although once I needed it running with low fuel level in tank however.
 
Over sizing a fuse defeats the whole purpose of using a fuse in the first place. The idea is to have the fuse blow before any wiring or device in the circuit is damaged.
 
If you wired the pump into the main switch circuit correctly, would you really need a separate fuse for the pump?
 
Hi there, a 30 amp fuse is way to high for your Airtex fuel pump circuit. I would think a 10 amp fuse would be correct if it is supplying only the fuel pump. Regards, Kevin.
 
39topless said:
If you wired the pump into the main switch circuit correctly, would you really need a separate fuse for the pump?
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On original wiring harnesses there are no fuses and/or circuit breakers on any of the wiring except the lighting. You would not normally wire a fuel pump into the lighting.
 
Wiring on the old pre-war 6-volt vehicles started out with no fuses at all to finally adding circuit protection for lighting and accessories. Cars in the model A era caught fire on occasion and burned up due to this. My Great Grandpop had an early Chevrolet car burn up back in the day and there wan't much left of it due to the high usage of wood in the structure. The lighting system was the most complicated electrical item in the post model A era until radios and heater blowers started to show up. The 6-volt systems needed larger wire gauge in order to efficiently transfer power due to higher resistance in smaller gauges. The larger the wire the larger the circuit protector. A 10 AWG wire conductor would need a minimum of a 30-amp in line fuse to protect it. A person can use a lower rated fuse but nothing higher then a 30. This is an abbreviated listing from an FAA Advisory Circular to give folks an idea of what the minimum fuse rating is for the size of American Wire Gauge conductors:
AWG = Fuse Rating
8 = 50-amp
10 = 30-amp
12 = 20-amp
14 = 15-amp
16 = 10-amp
18 = 10-amp
20 = 5-amp

There are different ratings for circuit breakers with AWG wire but these are more common in aviation so I won't list those. You can use a smaller fuse that is more protective of the load device but you can't use one any larger or the wire won't be properly protected from fire. If you ever see a wire burn from a short, you will know how quickly it happens and how much damage it can do. Wiring systems should be well dressed and protected from shorting against metal structure. A rats nest of old decrepit wiring is an accident waiting to happen.
 
rotorwrench said:
Wiring on the old pre-war 6-volt vehicles started out with no fuses at all to finally adding circuit protection for lighting and accessories. Cars in the model A era caught fire on occasion and burned up due to this. My Great Grandpop had an early Chevrolet car burn up back in the day and there wan't much left of it due to the high usage of wood in the structure. The lighting system was the most complicated electrical item in the post model A era until radios and heater blowers started to show up. The 6-volt systems needed larger wire gauge in order to efficiently transfer power due to higher resistance in smaller gauges. The larger the wire the larger the circuit protector. A 10 AWG wire conductor would need a minimum of a 30-amp in line fuse to protect it. A person can use a lower rated fuse but nothing higher then a 30. This is an abbreviated listing from an FAA Advisory Circular to give folks an idea of what the minimum fuse rating is for the size of American Wire Gauge conductors:
AWG = Fuse Rating
8 = 50-amp
10 = 30-amp
12 = 20-amp
14 = 15-amp
16 = 10-amp
18 = 10-amp
20 = 5-amp

There are different ratings for circuit breakers with AWG wire but these are more common in aviation so I won't list those. You can use a smaller fuse that is more protective of the load device but you can't use one any larger or the wire won't be properly protected from fire. If you ever see a wire burn from a short, you will know how quickly it happens and how much damage it can do. Wiring systems should be well dressed and protected from shorting against metal structure. A rats nest of old decrepit wiring is an accident waiting to happen.
Click to expand...
Good info rotowrench, thanks. old guy
 
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