cals400ex

iTrader: (27)

My fuel pressure guage said to put a 1 amp fuse in the 12V+ wire. However, I have my fues pressure, boost, wideband A/F, and cutout all wired to the same 12V+ wire going to the fuse panel. This will blow the 1 amp fuse in no time. What size fuse should I go with since these are all tied together?

WhiteBird00

iTrader: (4)

Fuses don't protect accessories - they protect the wiring going to the components to prevent overheating and possible fire in an over-current situation such as a short. So you don't select a fuse based on the accessory other than it has to be large enough to provide the amount of current necessary to run the accessory. The most important factor is the gauge and length of the wire going to the accessory.

If you are running 18 gauge wire to your gauges, you can safely run a 5-amp fuse for about five feet of wire. With 16 gauge wire you can increase that to either 7.5 amps over five feet OR 5 amps over about 15 feet of wire. Remember, the length of wire must include both the power wire and the ground wire because it is a single electrical path.

There are a lot of variables involved such as the type of insulation on the wire, whether the wire is in a bundle or "free air", whether the power source is constant or intermittent, etc. so the limits I mentioned are very conservative and won't apply to every situation.

cals400ex

iTrader: (27)

I am running approximately 4 feet of power wire and 4 feet of the ground wire. They both are 14 guage. I have no idea what type of insulation is on the wire. The power source is directly from the fuse panel (only on when the key is on).

WhiteBird00

iTrader: (4)

Eight feet of 14-gauge wire should be able to handle 10 amps easily. The gauges will be fine with 1-amp each (3 amp total) since they draw so little current but a cutout uses somewhat more power. I would recommend either a 7.5-amp or 10-amp fuse for use with your setup.