Compressors blow fuses?? help

I installed 2 viair 480's with 2 viair 40 amp relays and a 40amp in-line fuse. the compressors work fine for about a minute then the fuse blows. Is my in-line fuse too small....i have no idea what could be causing it. any help would be appreciated.

yes, you need an 80 amp fuse since your using 40 amps PER compressor, even tho it states they only pull 40 together...

the 480s only draw 19 amps each, so i'd say your wire size is too small and is causing the fuse to blow..... whats the gauge you are using?

I am running 10 guage power wire from my battery and to both compressors. and 14 guage wires to my pressure switch and 14 guage grounds.

all viair compressors claim to only use 19 amps each. this is true to a certain degree. what you have to realize is that viair rates their compressors on a 100psi scale. this is max amperage at 100 psi for a few compressors that leave their manufacturing facility. the actual amperage of a viair compressor is going to be more like 30 or 35 amps while in use. the more backpressure created on the other side of the inline checkvalve the more amps it takes to spin the electric motor. basically what im trying to say is that even though you run the relay your fuse is before the relay. you need at least the max amount of amps that your system will pull in your fuse. i would go no less than 100. the reason for this is because over time your compressors will begin to "break in". this will cause the compressors to have a maximum amp draw of about 45 to 50 amps each. you can still use the 40 amp relays for now but when you pop them just know that your compressors are well used and it might be time to get some new ones. Beau

your grounds are definatly to small.i would run a 10 gauge ground also.

So you suggest using a 100 amp fuse, increasing my ground wire to 10 guage,and then eventually getting bigger relays?. I had to order 40amp relays from viair because nowhere around here has any more than 30amp. what size relay do you suggest and where should i get them?

i run 100amp solloids for ambluance lights(similar to ford starter solnoids).

I've tested my viair 380 after my first installation and I've tested a 400 as well. The 380 actually draws less amperage at peak and a max of 23amps at around 160-170psi. Viairs are more efficient current draw wise at their peak.

Current will rise by bad connections, under-sized wires, and just straight up the longer wire you use theoretically the more current you're going to experience. If you're going to run 10+ feet of wire, go ahead and drop down a gauge leading to the compressor.

Don't run an 80amp fuse for 2 480's. You've defeated the purpose of a fuse by running a fuse that has a 100% capacity increase from what your rated peaks are supposed to be.

At the most, run a 50amp fuse, but the solenoid, you can run as big of a solenoid you want, but fuse it accordingly.

Just trying to help you out.

I have never dealt with those before... are they similar to a 4 terminal relay? how do you wire them?