On Board Air blowing fuses

Hooked this up this weekend:


I’m blowing 20 amp fuses after running about 30-45 seconds

Wire is 12 gauge from fuse block to pressure switch which then feeds compressor.

Do you think I have a wire problem or safe to run a 25 amp fuse?

Thoughts?

Thanks

 

A too small of a wire will not make fuses blow.

Find out how many amps the compressor is supposed to draw (maybe in the owners manual). Replacing a 20 amp fuse with a 25 amp fuse should be ok but find out how many amps it's supposed to draw first.

 

Double check your voltage coming from your battery. If your battery is old it may need replacing. Compressors require certain volts to run. Less volts then more amps will try to be pulled. Forcing the fuse to blow. Happened with my viair. When I would start it by itself it would run fine. If I put it on a tire and then turned it on it would blow a fuse under to much load. Ended up going arb.

 

Sticker on pump says Max 28 Amps. So use a 25Amp fuse? Or is a 30 asking for trouble?

 

Battery is nearly new Northstar 31M

 

25A fuse. Don’t do 30A.

 

What does your compressor recommend for the fuse? I would adjust your wire based on that. With that said, if its a 28A max I wouldn't go above 25A for the fuse. If you did go up to 30A for the fuse, make sure your wire is rated to handle the max appropriate amps. I'm guessing that its less than 30 ft of wire you ran to your pump, so as long as it's at least 10g copper THHN wire, you should be good for putting a 30A fuse in its stead. Just remember that your circuit is only as strong as its smallest gauge wire. Ensure your ground wire is also the same size or one size up (8 Gauge).



https://www.cerrowire.com/wp-content/uploads/2018/09/ampacity091418.pdf

Bottom line, 28A max draw would be found under the most extreme operating conditions (IE, extreme heat or extended operating times). A 25A fuse would protect your pump from damage due to heat fatigue by blowing all the time, even though your pump has a built in thermal protective device. I wouldn't run it to force that device to trip. The fuse is cheaper to replace than a burnt up pump or even worse, a melted truck so go with proper wiring and a 30A fuse.

-J

 

That's a no brainer, 30 amp fuse. But you should probably do the math to make sure the wire is big enough first.
https://www.google.com/url?sa=t&sou...FjALegQIAhAB&usg=AOvVaw3RKjAOkDltGnjiw-f6veGY

 

I made a screenshot of the exact same graph before you posted it LMAO!

 

I would really like to know how that would occur.

 

Great minds ... think alike.

Meaning that the truck burned down due to faulty wiring.

-J

 

Whoops, that's what happens when I get side tracked in the middle of a post. Ill go back and correct. If it's 30ft or less, 10g is the minimum, of course higher is better.

-J

 

Thanks all for the input!!

I’ll start with a 25Amp fuse and see if that holds before changing out the wire

 

You're going to keep blowing your fuse. Youll want to go up to a 30A fuse at minimum. If your wire run is 30ft or less, youll want 10AWG. If its more than 30 but less than 50ft, go with 8AWG wire. It all depends on how you have the wire routed. Again, keep your ground wire the same or one size bigger than your primary wire. This'll keep you right as rain.

-J

 

Definitely without a shadow of a doubt a 30 amp fuse or you're just begging for blown fuses. Make sure the wire is large enough gauge first. It's pointless to go with a 25 amp fuse and/or too small of wire.

 

Looks like you assembled the system yourself. Make sure you have a dump valve, that dumps the pressure on the pump when it shuts off. You should hear a PSSS when it shuts off. If the pump tries to start while there is pressure on the piston, you will see a big power spike. This detail is often overlooked when people build their own systems.

 

hmmmm...it was a complete boxed kit.
Pretty sure I used all the important looking pieces.

 

So I’ve gone through the parts list...comes with 20’ of 12 gauge wire and a 40 amp fuse. I cut off about 3’ of excess wire during installation and will use the supplied fuse and hopefully not inferno my truck.