power distribution blocks

[imral3 10+ year member]

hello everyone,

question... this is the first time i will be running two (2) amps of of a single power wire. do i still put a fuse near the battery on the main power wire as well as the fuses in the distribution block? if i will be using multiple fuses... does that change the fuse ratings?

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[tommyk90 5,000+ posts]

Yes, you have to have fuses at the battery and in the distro block. For the distro. block, use a fuse that matches the amp, and then at the battery get a big enough fuse that can support both amps. I don't really know the detail, but i'm sure somebody else does.

 

[imral3 10+ year member]

anybody else... how 'bout some long term senior vip's?

 

[ChefJoe 10+ year member]

You only need a fuse at the battery (for safety). This fuse should be equal to the sum of both your amps max draw (what their fuses are) or as close as you can get to that. The fuse at the battery is strictly to keep your car from having a huge fire if the wire gets knicked. The distro block fuses (if you use a fused distro block... imho, you're better off saving your $$ and just using an unfused/ground distro block) are there for people who anticipate only blowing one smaller guage fuse in the event they ground something between the amp and the distro block. You can use these to further "tune" when certain wires will have their fuses blow (if they need to blow at some point). Fuses are not reguarded as having any real effect on the current flow, though they do have a really minor one, but the way you're wiring is in series, so you just add the fuse ratings.

Anywho, my big gripe about all the fuses is that 90% of people properly working on their system will not blow fuses, and it just increases the number of places you'll have to check if you ever were to blow a fuse. After you figure out the time you spend looking for a fuse, the cost difference between the lighter guage fuses in a distro block vs at the battery is meaningless, you're just increasing the number of places you could have a problem.

About the only thing I could possibly see a fused vs unfused distro block being good for is in the event you somehow had a low current short that would be unable to blow the near-battery fuse... I guess it's possible, but I think it's extremely unlikely to have a "low current short".

 

[MikeofTulsa Moderator]

well u really only need a fuse at your batt to protect the wire in the car....any fuses at the distro block would be to protect the amps....i'd suggest both.......the fuse at the batt should be large enough for the given wire size....below is a link that will help a little.....and the fuse at the distro block should be close to the max current draw of the amps......peace

http://www.eatel.net/~amptech/elecdisc/wire.htm

 

[spyd3r 10+ year member]

Hey, Im not a senior member, but know my stuff in electronics and car audio.

I prefer using a circuit breaker under the hood --> distro. block --->Fuses for each amp.

I know that some people think of the fuses inside the car as pointless, but a fuse is a couple bucks and you will feel safer.

 

[MikeofTulsa Moderator]

when it comes to the higher amperage i'd use a circuit breaker but ive heard they are slower to trip than a fuse.....

 

[imral3 10+ year member]

thanks to everyone who responded and a special thanks to god for the link.

 

[MikeofTulsa Moderator]

no prob....thats what im here for