What to do with a FUSED Dist. Block when your amps already have internal fuses?

[Slody4Futbol 10+ year member]

because they draw the power.... if there is a short inside the amp... the amp fuse will blow... but if u have a short on the wire... would u rather have ur trunk catch fire? and burn ur car down? or $5 fuse pop?

 

[Colin P 10+ year member]

so why are there so many ANL fuses if each wire then should have a theoretical fuse to accompany it? I'm not arguing just trying to learn!

 

[Slody4Futbol 10+ year member]

because of all different types of wire... and some people like fusing according to the amp... and some things u can't learn everything about lol.. just know to fuse according to wire... cuz asking about the different fuses is like asking why hot dogs come in packages of 10 and hot dog buns come in packages of 8... they just do!

 

[johnecon2001 5,000+ posts]

so why are there so many ANL fuses if each wire then should have a theoretical fuse to accompany it? I'm not arguing just trying to learn!

A lot of fusing goes to how much the wire is going to draw as well. If you have a 1/0 home run to a dsitro, but only plan on running 1000 watts... you could lower the fuse rating at the battery to say a 150A. This wouldnt hurt the line, but it would prevent the wire from pulling anything over that 150A rating. In competitions you can only run so many amps through your system to compete in a certain class. So thats where all of those different sizes can come in handy.

 

[Colin P 10+ year member]

so if I change the fuse rating of my inline fuse (upgrade it, its 240 at the moment 1/0 wire) my system might sound a little louder?

 

[req 5,000+ posts]

no, the wire has the ability to draw more current.

the bigger the wire is, the more current i can handle, same as a pipe with water in it. the water can move at whatever speed (voltage) but the pipe itself can only hold a certain amount of water (amperage). we get BIGGER wire to supply our amps with their maximum current (amperage) draw. if we supply LESS than this - the amp wont be able to put out full power.

as for fuses, the fuse on the main wire at the battery is to prevent the 0 guage from catching fire in case it shorts because a screw is run thru it when you install it (or somthing else like a dog chewing on it) the fuse will pop, and the wire will be safe. and so will your car and even you.

but that fuse does NOT do anything for the 4 guage that you are splitting. think of it this way. the smaller pipes you are running off the larger pipes can NOT take the water pressure that the larger pipe can (amperage) and if you hook them up without a thingie that decreases the pressure (fuse) then they will burst and your house will flood (car catching on fire)

so when the wire breaks to two 4 guage - that means the bigger wire can handle (lets say) 300 amps. the two smaller ones might only be able to handle 100 amps each. and if that extra amount of power is drawn by the 4 guage wire shorting somewhere, it WILL catch on fire and you will be in trouble.

if you have a fuse at the beginning of the wire, then the fuse will break, and your life may be saved by a $2 fuse.

 

[johnecon2001 5,000+ posts]

Thats some good pipe laying req.

 

[BodegaBay 10+ year member]

...so when the wire breaks to two 4 guage - that means the bigger wire can handle (lets say) 300 amps. the two smaller ones might only be able to handle 100 amps each. and if that extra amount of power is drawn by the 4 guage wire shorting somewhere, it WILL catch on fire and you will be in trouble.
if you have a fuse at the beginning of the wire, then the fuse will break, and your life may be saved by a $2 fuse.

Great explanation. I agree that a main fuse is needed; in fact I will have a 150A ANL fuse at the battery to 1/0 guage. And I understand that fuses are needed to prevent fire to the amp at the distribution block. However, as I have recalled from past threads from other forums, one does not need fuses at the dist. block if the fuses are already in the amps themselves. So by logic, wouldn't internal amp fuses be doing the same thing as fuses at the distribution block -- thus negating their need?

 

[johnecon2001 5,000+ posts]

...However, as I have recalled from past threads from other forums, one does not need fuses at the dist. block if the fuses are already in the amps themselves. So by logic, wouldn't internal amp fuses be doing the same thing as fuses at the distribution block -- thus negating their need?

Wrong. If you step down the wire gauge at the distro block.. then you need to fuse that wire accordingly as well. Once again, the fuses on the amp are ment to protect the amp from internal damage. The fuses on the wire are ment to protect the wire from flaming into firey existance.

 

[Slody4Futbol 10+ year member]

you need to fuse at the distribution block... the fuse is going to pop between the short... and the source of power... so if there were to be a short on the smaller gauge of wire after the distribution block... why would a fuse on the amp blow?... it's not sending the power to the short... the battery is...

 

[BodegaBay 10+ year member]

Thanks for chiming in guys.

One thing I want to point out is how people differ on this subject. In searching throughout this and other forums, I found this interesting post at SD Forum: http://forum.sounddomain.com/forum/ultimatebb.cgi?ubb=get_topic;f=2;t=036615

Even JL Audio specifically (see Manville Smith's post in that thread) says that a fused distribution block is unesscesary for this type of situation. You can see where my confusion is coming from.

Even if the JL Audio is correct, I could still err on the safe side and use the fused distribution block that came with my amp kit, correct? Bottom line: would having 50A fuse at each 4 guage put additonal resistance to already fused amps?

 

[deaf tones 10+ year member]

The inline fuses are indeed to protect the wire. The Amps already have fuses on them for protection. If your wire shorts and starts carrying an ass load of current.. what would you rather have happen.. the amp roast or your car catch on FIRE.
Fuse to protect the wire.

uhhmm...what about those amps that don't have a built in fuse? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Where do you put the fuse? in the WIRE, right? So why is there a fuse in the wire going to the amp? To protect the amp. What about the fuses under the dash/hood? The ones going to the stereo and what not...are they there to protect those wires? Nope, the equipment they are running to.

Like said earlier...protect the wire all you want, i protect my gear.

 

[deaf tones 10+ year member]

ps...if you fuse correctly you are fusing to protect the CAR in general (and everything inside it)...f the wires man, seriously, they are cheap and very replaceable. If you care more about your wires than your car on a whole something's wrong.

and yes...don't even need to ask, I fuse under the hood, again before the aux batteries, and again right before the amps...the ones THAT DON'T HAVE BUILT IN FUSE HOLDERS.

 

[johnecon2001 5,000+ posts]

uhhmm...what about those amps that don't have a built in fuse? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Where do you put the fuse? in the WIRE, right? So why is there a fuse in the wire going to the amp? To protect the amp. What about the fuses under the dash/hood? The ones going to the stereo and what not...are they there to protect those wires? Nope, the equipment they are running to.
Like said earlier...protect the wire all you want, i protect my gear.

There are only a handful of amps that dont come with a built in fuse. Most of them are either over 10 years old or have extreme power ratings where reguardless of if you fused, if you caught a short or some other electrical problem, the amp would be toast. Most amps that dont have fuses on the outside in plain view have them on the inside.

Fuses under that dash.. have you ever looked at your radio? theres a fuse on it.. and one on the wire.

 

[deaf tones 10+ year member]

there are no fuses in nor on my amps or deck...believe me...i've checked. they are old...but not that old and yes, extreme power rating.

we are all on the same page here...trying not to start a fire. I would much rather replace a $0.30 fuse and a free piece of wire than my amps anyday. Fuse to protect the car and everything in it (including yourself)...not a cheap piece of wire.