How to select the proper fuse size

[RandyJ 10+ year member]

sticky?

its common knowledge that can be found by those who are not clued in on the field by a simple one word search, "fuse". For that reason, there is no need. There was a topic the other day for new stickys and it was determined that with such common questions like this, there really is no reason for it because the people asking will not take the time to read the stickies.

Also, for the arguement that peak ratings shoudl be used, acidburn said you are an idiot because peak ratings are never sustained for more then a few seconds. Even when you areplaying at max volume, that doesnt mean you are getting peak figures. Peak figures on an amp are kind of like the peak ratings for a fuse. You will never see the "2000watts" from that amp rated at MAX figures, simply because if it does put out anythingnear that, it is only when the caps are charged and there is energy to spare on a big burst of signal, which usually last for something like .75seconds.

 

[RandyJ 10+ year member]

Also, one thing i noticed whilst reading your sticky. You kind of made it sound like the amp in question, the class d one, will be pulling 150A all the time. This isn't the case for those of you who don't know. The amp will only pull that at near max lvls.

 

[xshort_ex 10+ year member]

so can you use a 150 amp fuse for the 1500 watt amp???

*sorry if its a noob question*

 

[Silver 10+ year member]

yes sir.

Great topic! Alot of info.

As for the underhood fuse. Isn't it required to run it atleast 12in away from the fuse box or battery?

 

[PRIVATEpastry 10+ year member]

sticky?

x3

 

[powerhouse604 10+ year member]

hmmm i have a pg 150a, would that be good enuff for a 2500d?

 

[Papaloads 10+ year member]

First off I would like to thank the contributors of this thread greatly.

Second, I had a question about how to calculate the fuse size required for the distribution block.

Background:

I followed the steps to calculate my total system current draw and my final number is:

171amps

JL Audio 1000.1 = 101amps

Kicker KX600.4 = 70amps

I will be purchasing

0/1 gauge wire:

http://www.knukonceptz.com/productDetail.cfm?prodID=KFX0R

300 amp max

Used from battery to distribution block

In-Line Waterproof ANL Fuse Holder w/ 250amp Fuse

http://www.knukonceptz.com/productDetail.cfm?prodID=FH-20

Used within 18 inches of battery terminal

4 gauge wire:

http://www.knukonceptz.com/productDetail.cfm?prodID=KFX4R

150 amp max

Used from distribution block to amps

Distribution block:

http://www.knukonceptz.com/productDetail.cfm?prodID=KNF-12

My question is how do i figure out what fuse size I need for the distribution block?

the options are 30amp-150amps

Also if anyone could recommend other sites that sell the above/comparable materials for less that would greatly be appreciated.

I will also be doing the big 3 using the same 0/1 gauge wire

I believe one of the big 3 requires an inline fuse between positive battery post and alternator.

Could I use another In-Line Waterproof ANL Fuse Holder w/ 250amp Fuse for this step? or should the fuse be a different size? If so how would I figure out the correct fuse size required?

Thanks in advance for all your help!

 

[Amandab]

so can you use a 150 amp fuse for the 1500 watt amp???

*sorry if its a noob question*

 

[Firewalker]

@Popwarhomie

 

[Popwarhomie 5,000+ posts]

 

[Eviljacket]

This may be a newb question, I’m just starting to really dig into proper custom fusing, but why do some amps have built in fuses and some don’t? Say my Alpine MRX-M110 has 100amp fuse built in (4x25amp) but my Orion 2500D does not have any fusing, I think I read somewhere 250amp is what’s best for these at 1ohm, I’m in the process of switching these 2 amps so any insight in fusing the Orion 2500D @ .7ohm would be cool, I keep reading stuff that sounds like fusing is based on what the amp will pull, not what the wire will take. I want to protect the amp as well as my wiring, I’m running single 2awg from battery split to 2x 4awg to amp 4awg inputs. Planned on going with 120 amp fuse on each of the amps 4awg leads and a 250 amp breaker near under hood battery. Was reading 250-300 amp fuse is good for this early Class D mono block for the 1-.5ohm range. I’m just reading from multiple sources that the fusing is to protect the wiring but isn’t also to protect the amp? Or am I just thinking all newbish and wrong? I plan on clamping this amp soon as it’s hooked up to know what I’m pulling at max and general ride listening volumes, gains set with my Oscope to prevent clipping of any sort.