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Fused distribution block

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Fused distribution block

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i am installing an alpine mrv m500 mono and alpine mrv f300 4 channel.( running slow with the install waiting for nicer weather) Both amps have installed fuses. Plus I have the inline fuse by the battery. Should I also use a fused distribution block or is this overkill, if needed what amp should I use?Also, my amp wiring kit( Rockford fosgate dual 4 gauge) came with a 100 amp fuse. Is this a good size for those two amps.

Verified Answer
  • Thanks Weigel21. The wire I'm using is true gauge pure copper from a Rockford Fosgate dual amp kit. I'm trying to do this right the first time so I've purchased the amp kiit along with jl audio 4ch & 2ch RCA cables, 10 GA pure copper for the sub and 14 GA pure copper for the speakers. Your response definitely helps point me in the right direction and puts my mind at ease since this is my first major install. I'll probably stick with running the 4GA from the block to the mono since it causes no harm even though the distance from the block to both amps shouldn't be more then a couple feet each. The install won't take place till May or June since I don't have a garage and it's cold outside.I'm sure between now and then I'll have to tap your brain again. Thank you

All Replies
  • Both amps have on-board fusing to help protect themselves. Your amp kit came with a 100AMP fuse to protect the wire from seeing too much amperage and risking a fire. The two amplifiers have a combined fuse rating of 100AMPS as well, though it's very unlikely they well ever demand such, if they do, you'll get severe headlight dimming at best and it'll kill the engine at worse (meaning it'll cause the engine to cut off, no actual damage to the engine). That's assuming you have a stock electrical system.

    If you use the 4GA wiring of the RF kit for all the power runs, then you are fine without using a fused distribution block. After all, you fuse to protect the wiring first and foremost, which it will have the 100AMP fuse within 18" of the battery. "If" you run 8GA from the distribution block onward to one or each amp, then you'll want to fuse appropriately for this wiring.

  • If I understand what your saying since I will be splitting it from 4GA TO 8GA I should use the fused distribution block. Also, could I run one 4GA and one 8GA from the distributor block due to the mrv m500 recommending 4 GA. I believe in a previous post you said I should be ok with the 8GA as long as I kept it short from the block. But if it's ok to run one 8 and one 4 would this be a little safer.

  • One more quick one, would it benefit me to use a capacitor? I didn't think I was putting out that much to require one.

  • It is true that wiring can handle more amperage when the length of the wire is shorter. However, I don't wish to make a blanket statement that it is safe to do in any situation. I know not how long of a run the 8GA would be or if it's true to gauge, nor do I know if it is pure copper, tinned copper, or copper clad aluminum.

    Truth be told, both amplifiers should be fine with merely 8GA, I mean the M500 can't pull much more than 60AMPS before the on-board fused blow and I've only seen some really cheap copper clad aluminum kits come with less than 60AMP inline fuses.  But yeah, one run of 4GA to the M500 and one run of 8GA to the F300 would be fine. As for opting to not fuse the 8GA with it's own inline fuse, make sure you are using true to gauge 8GA that is either pure copper or tinned copper and try to keep the run of wire short, like less than a couple feet.  Fusing the 8GA with it's own fuse is just an extra safety precaution.

    As for the need of capacitor, I'd not bother with it. As I said, those amps are not going to be demanding the combined amperage of their fuse ratings. If you do notice any issues with dramatic headlight dimming or worse, then a capacitor is pretty much going to mask the underlying issue of an insufficient charging system.

    Me, I'm running an Alpine CDA-117, Imprint processor, Rockford PBR300X4, and JBL MS-A5001 on the stock electrical system of a 99' Cavalier RS. It's got but a 105AMP alternator and the combined fuse rating of my stereo system is 127.5AMPS. I am severely limiting output of the MS-A5001, running at 2 ohms with gain set for 400RMS@2 ohm, but have the gain for my mids set for maximum clean output, gain for my tweeters is set to allow the tweeters to blend with the mids.

    No idea off hand what my system pulls, but unless I crank it up and push it to the limits (which I did once just to see what it was like and it caused the voltage to drop enough for the MS-A5001 to kick off), I have zero issues. As it stands, I seldom exceed 25/35 on the master dial and the sub volume is usually set anywhere from 2-5/15. So yeah, I'm not even asking my system to break a sweat under typical listening levels.

  • Thanks Weigel21. The wire I'm using is true gauge pure copper from a Rockford Fosgate dual amp kit. I'm trying to do this right the first time so I've purchased the amp kiit along with jl audio 4ch & 2ch RCA cables, 10 GA pure copper for the sub and 14 GA pure copper for the speakers. Your response definitely helps point me in the right direction and puts my mind at ease since this is my first major install. I'll probably stick with running the 4GA from the block to the mono since it causes no harm even though the distance from the block to both amps shouldn't be more then a couple feet each. The install won't take place till May or June since I don't have a garage and it's cold outside.I'm sure between now and then I'll have to tap your brain again. Thank you