# question about grounding multiple amps



## alex912005 (Jan 8, 2014)

Hello guys, I need some advice on grounding multiple amps. Right now I've got an Alpine MRV-M500 powering a 12 inch Kicker L3. I'm going to get an Alpine MRV-F300 for mids and tweeters in the near future and just want to clear this up so I'll know what to get. 
I have a (supposedly) 0 gauge cca cable (i think) which will go to a distribution block and split into 2 4 gauge wires (hopefully will fit the F300). 
Now here's the question: should I do the same thing with the ground ? the 2 4 gauge ground wires from each amp to a distribution block and my current ground cable (also 0 ga of course) ? Or should I ground the 2 amps to the same spot without the distro block and without the 0 ga ground cable ? I know that you're supposed to have the same thickness of power and ground cable...


----------



## REGULARCAB (Sep 26, 2013)

As long as both amps are grounded to the same spot you should be able to avoid ground loop. Runing to a distro or running both grounds to the same spot ends up with the same result. It would just depend on how you want it to look.


----------



## alex912005 (Jan 8, 2014)

So it doesn't matter if the power is coming from 0 ga and the ground is 2 4 ga wires ? (not being the same thickness) I really don't care about the look, I just want it to work and be safe...


----------



## ShaneInMN (Sep 27, 2013)

Make sure your 0 ga power coming in to the amps is split off into a fused distribution block. I believe the amps can take up to 4 gauge power/ground. Then use the same gauge ground as your power. It doesnt matter if you ground to the same spot, different spots, or use an unfused distribution block for your grounds. Wherever you ground needs to be on bare metal, preferrably to the vehicle's chassis.


----------



## alex912005 (Jan 8, 2014)

So what kind of fuses should i use ? Same size as on the amps ? (a 40 and a 60a)


----------



## ShaneInMN (Sep 27, 2013)

Check this out - 

http://www.bcae1.com/images/swfs/systemdesignassistant2.swf


----------



## alex912005 (Jan 8, 2014)

That says that with my setup I should use a 35a fuse for the m500 (which has 2 30a fuses) and a 15a fuse for the f300 (which has a 30a fuse on it). Seems kinda low... And for the battery an 80a (right now I have a 150a and I only have the m500)

Here's a pic of what figures I used:


----------



## ShaneInMN (Sep 27, 2013)

Just get some fuses rated a little below what the amps are rated for, that way those will blow before it reaches the amps. I don't know the actual effeciency of these amps, but I think 75-80% is a good ballpark. I have over 1000W RMS 2x Class D amps, and only 120A fuse at the battery.


----------



## RNBRAD (Oct 30, 2012)

Fuse to the wires capability not your amps. Fuses are to protect the wire not the amplifier. Amplifiers have their own fusing. Hopefully your wires capability supersedes your amps. Many do not and then they fuse to the amps rating and this could be a problem. Anyway fuse to the wire not the amp!!


----------



## Darth SQ (Sep 17, 2010)

Subscribed.


Bret
PPI-ART COLLECTOR


----------



## Alrojoca (Oct 5, 2012)

I don't want to disappoint, excellent advice given so far, but 0 gauge for those Alpine amps under 800 watts total? Alpine amps even being AB class in some cases are not power hungry. It is an overkill.

Both amps will need to have more than twice the power rated to justify the 0 gauge wire.

Even just gauge 2 wire is more than enough, they both could operate safe off a single gauge 4 wire unless the power cable run is over 20 feet.

If the amps will be upgraded later I guess might as well use 0 gauge both of these amps can operate safe with 8 gauge wire each if wires are shorter than 10 feet.


----------



## alex912005 (Jan 8, 2014)

@RNBRAD: Then what fuses should I use on the distribution block if I split the 0 ga power into 2 4 ga ? At the battery I have a 150a fuse; too much ? Also would the amps survive blowing their own fuses ? I've been told they don't (but car audio installers in my country are very dumb).


@Alrojoca: I already have one amp installed with 0 ga, I figured it couldn't hurt to use bigger wire than needed (keep in mind that it's cca not ofc), wasn't sure about how to ground the whole thing when the next amp comes.


----------



## RNBRAD (Oct 30, 2012)

Always check the manufacturers amp rating and fusing recommendation of their wire you are using. Realize not all wires even of the same size are created equal and can vary greatly in power transfer and resistance. Many are aluminum and some are % of copper. Some are advertised at 4g but realistically closer to a 6g wire. This is why I say check with the manufacturer and know who is making your wire before you buy it and what it's made of and how it's rated.


----------



## ShaneInMN (Sep 27, 2013)

I'm not going to get in over my head, but I'll give you another link to read up on fusing.

FUSES

The fuses are to protect the individual wire segments. You want to make sure that you're not fusing too low that the amps will blow them and not too high that they're rated more than your power cable is designed to handle.

Wire Sizes and Fuses

Your 0 gauge running those amps is overkill but that's ok, you have 150A amp fuse protecting the power wire at the battery. You can fuse the segments from the distribution block with 2 60A fuses and be fine. As you can see from the pic you posted, you're amps aren't drawing that much current. Consider the fact that music is also dymanic, you're going to be pulling a lot less amps than you may think.


----------



## alex912005 (Jan 8, 2014)

@ShaneInMN: Ok thanks for the advice, guess I'll be using 2 60a fuses for the 4 ga wire segments.
@RNBRAD: I'm gonna use XS Power XS Flex 4 ga ofc wire, the only decent wire I have access to...


----------

