fuse amp?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=27724
Printed Date: November 22, 2025 at 8:47 PM

Topic: fuse amp?

Posted By: BangBang
Subject: fuse amp?
Date Posted: March 04, 2004 at 2:33 PM

the fuse in the fuse holder for my 4 guage wire to a distribution block wut fuse should i use ?

i just upgraded shietz to a 4 gauge and it sounds like crap u know y?

Replies:

Posted By: DYohn
Date Posted: March 04, 2004 at 2:59 PM

The size of your power cable will not affect sound quality. Use the correct size fuse for the load you are putting on the system. 4AWG wire is rated at 105A max per NFPA70.

Shietz? What is a shietz? Like what's on your bed?

Posted By: BangBang
Date Posted: March 05, 2004 at 5:34 AM

DYohn] wrote:

p>The size of your power cable will not affect sound quality. Use the correct size fuse for the load you are putting on the system. 4AWG wire is rated at 105A max per NFPA70.
Shietz? What is a shietz? Like what's on your bed?

yeah after trying to installed 2 amps it dint' sound nice. so i reinstalled back my old stuff... the 8 guage geear. and it sounded insane. like it was brand new... wut went wrong?

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Posted By: Clean Install
Date Posted: March 05, 2004 at 5:41 AM

what type of power cable to you run?

the 4awg and the 8awg

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If we learn from each success and
each failure, then we can improve ourselves

Posted By: Clean Install
Date Posted: March 05, 2004 at 5:55 AM

say by the way to figure out what size fuse you will need all you have to do is take the rms of your amps and divide it by your vehicles idle voltage

400watts(rms)/12.6volts=31.8amps

so you would need about a 30-40amp fuse

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If we learn from each success and
each failure, then we can improve ourselves

Posted By: DYohn
Date Posted: March 05, 2004 at 8:35 AM

If the sound quality of your system changed by running diferent power cables then you changed something else as well. Power cable by itself will not affect the sound quality of an amp other than adding noise or hum or buzz if you do something wrong. Is that what you are talking about?

Posted By: Paradigm
Date Posted: March 05, 2004 at 9:54 AM

CLEAN INSTALL wrote:

say by the way to figure out what size fuse you will need all you have to do is take the rms of your amps and divide it by your vehicles idle voltage
400watts(rms)/12.6volts=31.8amps
so you would need about a 30-40amp fuse

Can someone please verify this? I do not think this is right. I thought all that told you was how many ADDITIONAL amps you will be adding to your total load. Help please, anyone?

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VEHICLE: 2002 GMC Sonoma ZR2
Alpine CDA-7940
AudioControl EQT x2
JL Audio 1000/1
JL Audio 10W6 (originals) x3
Kicker ZR120
Kicker ZR460
Polk GXR-6 x4
Polk GXR-4 x2

Posted By: DYohn
Date Posted: March 05, 2004 at 10:01 AM

Basic ohm's law. In a DC system, P=IE, or (P)power = (I)current X (E)voltage. So Current = Power/Voltage. You would always use the total power (RMS) of all amps and other equipment being fed off a circuit.

Posted By: Prophit
Date Posted: March 05, 2004 at 10:09 AM

It might be your ground too.. Might want to check to see if the ground wire if 4Guage is solid.. Normally when this happens i like to connect it directly to the battery.. if theres a change then its a bad ground.. Might want to make sure your connected to bare metal. Sand or grind away any extra paint chips.. Along with make sure your using an effectient size connecter and bolt.. No point in using 4 guage if your bold is half the size of the cable.. Try that and see if that makes any difference.. Also as for a fuse.. i would recomend atleast 30amp..

Posted By: wayland1985
Date Posted: March 05, 2004 at 10:35 AM

Don't run your RCAs on the same side as the power cable.....that may be ur problem if you did that.....bigger wire can hold more power....more power+rca's(nearby)= decreased SQ

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~WAYLAND

Posted By: Paradigm
Date Posted: March 05, 2004 at 11:01 AM

DYohn, I knew that formula already. Thanks for posting it again, though, for those who may not have known. But if I'm hooking up 3 amps, one with a 100A fuse (1000W RMS), one with a 30A fuse (30W RMS x2), and the last one with 2 30A fuses (30W RMS x 4), are you saying all I need to use for an inline fuse from the battery is roughly 90-95 amps?

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VEHICLE: 2002 GMC Sonoma ZR2
Alpine CDA-7940
AudioControl EQT x2
JL Audio 1000/1
JL Audio 10W6 (originals) x3
Kicker ZR120
Kicker ZR460
Polk GXR-6 x4
Polk GXR-4 x2

Posted By: Paradigm
Date Posted: March 05, 2004 at 11:03 AM

And should I go less than or greater than the resultant amperage (was 93.xxxx amps after the calculation)?

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VEHICLE: 2002 GMC Sonoma ZR2
Alpine CDA-7940
AudioControl EQT x2
JL Audio 1000/1
JL Audio 10W6 (originals) x3
Kicker ZR120
Kicker ZR460
Polk GXR-6 x4
Polk GXR-4 x2

Posted By: DYohn
Date Posted: March 05, 2004 at 11:41 AM

Paradigm wrote:

DYohn, I knew that formula already. Thanks for posting it again, though, for those who may not have known. But if I'm hooking up 3 amps, one with a 100A fuse (1000W RMS), one with a 30A fuse (30W RMS x2), and the last one with 2 30A fuses (30W RMS x 4), are you saying all I need to use for an inline fuse from the battery is roughly 90-95 amps?

For your main power, you will need to add up all your amps to determine the total load. You ave listed 1000W + 30W X2 + 30W X4 = 1180 watts total. Divided by nominal 12 volts = 98.33 amps. This should be the total load when all amps are running at maximum RMS power (assuming the RMS ratings listed by the amp manufacturers are accurate.) Use a slow-blo 100A fuse in your main feed at the battery. The fuses in the amps are designed to protect them from over-excursion when hitting momentary peaks. If you end up blowing the main fuse, you are probably over-driving the amps or the ratings are wrong.

Posted By: Paradigm
Date Posted: March 05, 2004 at 11:59 AM

Thanks for the info.

The wiring kit I bought came with a 250A fuse. I guess that would be way to high to use in my setup posted_image

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VEHICLE: 2002 GMC Sonoma ZR2
Alpine CDA-7940
AudioControl EQT x2
JL Audio 1000/1
JL Audio 10W6 (originals) x3
Kicker ZR120
Kicker ZR460
Polk GXR-6 x4
Polk GXR-4 x2

Posted By: amickracing
Date Posted: March 05, 2004 at 5:31 PM

Newbie question...
I'd think a 250a fuse would work fine (assuming your using monster wire, not something small). The main fuse just protects the wire, the fuses in the amp protect the amp. Right?

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Posted By: forbidden
Date Posted: March 05, 2004 at 5:43 PM

Your right Lynn, add to it that it will also protect an amp that does not have an internal fuse (fuse it separately close to the amp if possible) and the fact that it also protects the vehicle from a short circuit.

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Top Secret, I can tell you but then my wife will kill me.

Posted By: DYohn
Date Posted: March 05, 2004 at 7:41 PM

Yep, the 250 A fuse is fine to use as long as the power cable is 1 or 2 gage. The main fuse is to protect the cable from frying and as Rob said, the amplifier fuses will protect those.

Posted By: Paradigm
Date Posted: March 06, 2004 at 8:57 AM

Yeah, the kit is a 0 GA. kit, for up to 3400 Watts (from Stinger). Came pre-packaged with a 250A fuse. I actually bought a seperate 200A fuse to use instead because I thought 250A would be more than I needed.

Thanks for all the responses, guys. This is really helping me out a lot posted_image

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VEHICLE: 2002 GMC Sonoma ZR2
Alpine CDA-7940
AudioControl EQT x2
JL Audio 1000/1
JL Audio 10W6 (originals) x3
Kicker ZR120
Kicker ZR460
Polk GXR-6 x4
Polk GXR-4 x2

Posted By: defective
Date Posted: March 06, 2004 at 12:10 PM

always use the least amount of fuse needed. It is OK to have a 250 amp fuse but if you can help it, use the rated fuse for your amp draw. Better safe than sorry....

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