# What's the general rule for inline fuse sizes?



## Gundam (May 18, 2006)

Is it based off the total amount of amps that your system is using or the amount the wire can handle? I have an Audison amp that uses 30amps hooked up to 4gauge wiring straight to the battery (with an inline ANL fuse holder of course) The first time I turned it on, the 30amp inline fuse popped immediatly. I had a 120amp fuse laying around so I tried that and it worked. So is it okay for me to continue using the 120amp fuse in the inline holder?


----------



## Mless5 (Aug 21, 2006)

Depends on the wire size. Chapter 14:

http://www.bcae1.com/


Suggested Fuse Sizes:

Wire Gauge	Recommended
Maximum Fuse Size
00 awg	400 amps
0 awg	325 amps
1 awg	250 amps
2 awg	200 amps
4 awg	125 amps
6 awg	80 amps
8 awg	50 amps
10 awg	30 amps
12 awg	20 amps
14 awg	15 amps
16 awg	7.5 amps
These are the recommended maximum fuse ratings for the corresponding wire size. Using a smaller fuse than what's recommended here will be perfectly safe.


----------



## azngotskills (Feb 24, 2006)

While i do agree with you, i make sure im using the proper guage wire for the amps and fuse the wire using the fuse ratings on the amp. I would rather blow the inline fuse rather than the ones on the amp


----------



## Gundam (May 18, 2006)

azngotskills said:


> While i do agree with you, i make sure im using the proper guage wire for the amps and fuse the wire using the fuse ratings on the amp. I would rather blow the inline fuse rather than the ones on the amp


So if I'm using the 120amp fuse and my amp only draws 30amps, then the fuses on my amp would blow before the fuses on the inline holder?

What is the rule for determining inline size then? Is it the total amount of amps that your amplifers use, or is there more to it? I only have one amp rated at 30amps, and the 30amp inline fuse immediately blew when I connected the battery.


----------



## azngotskills (Feb 24, 2006)

yes the fuse at the amp would blow first....to determine the fuse rating of the in-line fuse, i total up the fuse rating on the amp itself and try to find one close to it.

was your car on when you connected the fuse? was the negative terminal disconnected when you where working on your system?


----------



## Gundam (May 18, 2006)

azngotskills said:


> yes the fuse at the amp would blow first....to determine the fuse rating of the in-line fuse, i total up the fuse rating on the amp itself and try to find one close to it.
> 
> was your car on when you connected the fuse? was the negative terminal disconnected when you where working on your system?


Both the positive and negative were disconnected while I was hooking everything up. I then hooked up the positive cable, then the negative, that's when it blew.


----------



## azngotskills (Feb 24, 2006)

hmm....im not really sure what happen because i have never had a problem like that  maybe a faulty fuse? maybe someone more experience can chime in and help us out


----------



## HIS4 (Oct 6, 2005)

The inline fuse at the battery and the fuse at the amp are protecting 2 different things. The battery fuse should protect your main power cable which should be sized large enough to supply power to all your amps. So based on your 4 AWG cable, the 120A main fuse is fine. The amp fuse will protect the amp from an overcurrent condition coming into the amp. That fuse should be sized per the manufacturers recommendation.

So if your 30A fuse popped immediately, I would first check what the manufacturers recommendation for that fuse is. 30A seems a little small for an Audison amp unless there's more than one fuse. If 30A is the right size, then I would check yourm power and ground cable to make sure there are no shorts somewhere between the battery and the amp.


----------



## Hillbilly SQ (Jan 26, 2007)

i always fuse at or a little below what the amps are rated. my amps are fused internally at 50amps and the 8awg going to them is fused at 50amps. the 4awg for the big 3 and going from batt to distro is both fused at 80amps. i've never blown a fuse under normal use doing it this way.


----------

