Amp Fuse Question

[Gouranga]

I got an alpine amp which has 2 x30amp fuses in it.

my question is : does the fuse by the battery has to be a 60 or is it suppose to be a little bit more like an 80 / 100

I was always told it has to be a little more than the fuse on the amp
but the wires I got used from some guy that came with the amp already have a 60 fuse (on a power wire next to the battery) while the amp has 2x30fuses so I dunno if its right to have 60 and 60

[laserguy]

That is no longer the case . It depends on the wire gauge size used to power the amp.

8 gauge wire uses up 60 amp fuse, 4 gauge (80-120amp fuse)

[hofffam]

The purpose of the amp's fuses is to protect the amp. They will blow if the amp malfunctions or otherwise draws too much current from the electrical system.

The purpose of the fuse on the power line is to protect the electrical system of the vehicle. That power line often supplies 12V to more than the amp so it is common for it to have a larger fuse than the amp's fuses.

I'm not sure why the cable size should determine the fuse size. The cable size should be chosen to adequately supply the amount of current that might be drawn on that cable. If you by chance used a beefier cable than necessary, I would not use an arbitrarily large fuse. The fuse should be located near the battery to limit the chance that the power line would overheat and cause a fire before the fuse blows.

So I would choose a battery fuse 10-20% larger than the amp assuming no other significant draws on that line.

[Gouranga]

damn

I only have 150A fuse lol... and the 60A fuse that my wiring kit came with.
its a 4guage wire with a 60Fuse on it and there are 30Ax2 on the amp

and I really dont want to go find myself an 80 (which would be perfect)

so what should I do.. stick with the 60 fuse by the battery or put in the 150 I have...?

60 60 or 150 60

[DaveG55]

Cable size and fuse size should only be related in that you want the master fuse to be a smaller size than the rating of the cable. I would say a good 20% smaller for safety sake. But what I would actually fuse it for, on a single function circuit, is right at or just barely under the max rating for the powered device.
Anyway according to this chart, 4 Ga wire is only rated for 60A for power transmission, 135 for chassis wiring so I would never fuse it at more than 110A for whateve purpose.
http://www.powerstream.com/Wire_Size.htm
As for the OP's original question, If you have 2 30A fuses in the amp then the largest main fuse you want is 60A. This link may help you in deciding what you want to do to supply power to your amp.
http://carstereochick.com/blog/2011/...-for-your-amp/

[laserguy]

Originally Posted by Gouranga

damn

I only have 150A fuse lol... and the 60A fuse that my wiring kit came with.
its a 4guage wire with a 60Fuse on it and there are 30Ax2 on the amp

and I really dont want to go find myself an 80 (which would be perfect)

so what should I do.. stick with the 60 fuse by the battery or put in the 150 I have...?

60 60 or 150 60

Yeah! no problem, you will be fine, use the 60 amp fuse, if it blows get an 80 amp one. You could have an issue using a much bigger fuse like the 150A with the 4 gauge wire. It's about staying within the upper limits, below the lower limits is not a big issue unless the amp delivers over way more power of maybe over 600 watts rms.

[laserguy]

Mmm, I guess times have changed, I have gathered info on the latest advice and what it is being done moving forward.

4 years ago, they would sell you a 4 gauge wiring kit with a 60 amp fuse, now assuming it is fresh and of the best quality ones and packed recently, you see no 4 gauge kits with 60 amp fuses, only 80-120 amp fuses.

[Gouranga]

you might not believe it but ive had no less than 100 systems of all kinds in my cars in the past 10 years.

Ive had anything from 2 JL w7s with 2 1000rms JL 1000/1 amps to Kicker L7 to MTX 9500 series

and only once ive had 2 guage power wire ,, actually I had a 0 gauge before but It was heavy and I got the 2guage...

most of my systems seen 1000rms on 4guage power wires with zero issues but I always had the fuse by the battery a little higher than amp fuse

for the first time in my life im only having a small 100'' subwoofer and a 500rms alpine amp (in the ridgeline)
so I never dealt with an amp that only has a 60AMp fuse in total

so from my expierence I should be getting a 80amp fuse but if you guys think a 60 will do just as good 60batt fuse/. 60 amp fuse

than ill try that and save my 150amp fuse for another day lol

as for the 4gauge power wires only being able to handle 60guage thats complete BS... ive always had 100-120amp fuses for years with zero problems

[laserguy]

Originally Posted by Gouranga

you might not believe it but ive had no less than 100 systems of all kinds in my cars in the past 10 years.

Ive had anything from 2 JL w7s with 2 1000rms JL 1000/1 amps to Kicker L7 to MTX 9500 series

and only once ive had 2 guage power wire ,, actually I had a 0 gauge before but It was heavy and I got the 2guage...

most of my systems seen 1000rms on 4guage power wires with zero issues but I always had the fuse by the battery a little higher than amp fuse

for the first time in my life im only having a small 100'' subwoofer and a 500rms alpine amp (in the ridgeline)
so I never dealt with an amp that only has a 60AMp fuse in total

so from my expierence I should be getting a 80amp fuse but if you guys think a 60 will do just as good 60batt fuse/. 60 amp fuse

than ill try that and save my 150amp fuse for another day lol

as for the 4gauge power wires only being able to handle 60guage thats complete BS... ive always had 100-120amp fuses for years with zero problems

That's right, this site on this link below is pretty good and confirms some things I mentioned.
http://www.bcae1.com/fuses.htm

[Gouranga]

from the website

''Any fuse rated at less than ~150 amps is sufficient to protect a 4g wire and the vehicle but I generally recommend a 125 amp fuse with 4g wire.''


im not reading all that so much stuff lol

did it mention anything about running the same fuse size as the amp has ?

so 60 by battery and 60 in the amp ? or did it in fact recommend to use a higher batt fuse like 80 if the amp is 60 this is what I really must know