12v Questions

[humphrey Junior Member Find all posts View Profile Close humphrey]

I have two questions in relation to wiring if someone could please shed some light.

1. If I put one of these down the back -



the what size fuse/circuit breaker do I install at the battery end? I've seen people use 60amp, but then others have said that's to big, and then I've seen people use 100amp. Is there a formula to work this out?

2. If I wish to run a compressor (50amp) or inverter (35amp) and the above fuse holder is only rated 30amp per circuit, should I wire each item into a distribution block prior to the fuse holder, and then run two separate wires to each item, wiring each its own fuse in a holder that's rated accordingly?

Thanks

[wolfcub Lurker Find all posts View Profile Close wolfcub]

Re: 12v Questions

Hi Brett,

The fuse/circuit breaker at the battery is only used to protect the cable running from the battery to your fuse block or accessory. Therefore, the size of the fuse/circuit breaker is completely dependent on the size of the cable used.

It is always suggested that you should err on the side of caution and use a larger size wire for your application than necessary. The pictured fuse block has max amp rating of 100 amps. Depending on the brand, 6 gauge wire has an amp rating of anywhere from 100-125 amp, so will be sufficient for the fuse block. Therefore a fuse/circuit breaker of 100 amp or less will be ok.

I would recommend that you wire any high amp devices like compressors or inverters direct to the battery. If you want run these devices off the same wire that you run through the vehicle, then I would suggest a busbar or power post.



Hope this helps.