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Recommended Wire Gauge for Amp?

Discussion in 'Gen 2 Prius Audio and Electronics' started by ~sparky~, Jun 26, 2005.

  1. ~sparky~

    ~sparky~ New Member

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    I recently installed an Alpine MRP-F240 Amplifier (50x4 RMS at 2 ohms) in the 'hidden compartment' under the rear cargo area in my 2005 Driftwood Package 4 (AM). Details on that installation are under my separate post, but my question concerns wiring:

    I originally installed using 4 gauge wire from an amp kit I purchased, but had problems, so I replaced both the 4 gauge power and ground wires with 14 gauge . Everything works just fine, but I'm just concerned with whether the 14 gauge is large enough...

    Any concerns with sufficiency of 14 gauge power & ground wires for this amp? Am i going to melt the compartment or short something out?

    [Broken External Image]:http://members.cox.net/sparky0480/amp_+_sub_installed.jpg

    Any advice appreciated. Thanks.
     
    #1 ~sparky~, Jun 26, 2005
  2. wilco

    wilco New Member

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    Depends... How long is the wire? How loud do you usually listen? Just off the top of my head, I'd say that 14ga is a little small for that amp, but if the length is less than three feet you'll probably be fine.

    There are two ways of going about this. The first is to do the math, taking into consideration the length/gauge of the wire and the current draw, and alternator/battery voltage. The second - and far easier - way is to look at the fuse. Here are some ballpark figures (from an old chart I had in my workbench drawer) on what the min. wire gauge to use would be based on the value of the fuse recommended by the amp manufacturer.

    Fuse--------Wire
    80 amps---6 awg
    50 amps---8 awg
    30 amps---10 awg
    20 amps---12 awg
    15 amps---14 awg
     
    #2 wilco, Jun 26, 2005
  3. HYACK

    HYACK New Member

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    I'd concur with that 'old chart' of yours, based on the 8ga wiring kit my installer has selected for the 40A x1 fuse rated 50w x 4 amplifier I'm having installed.
     
    #3 HYACK, Jun 27, 2005
  4. wilco

    wilco New Member

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    <div class='quotetop'>QUOTE(HYACK\";p=\"101938)</div>
    The way you put 'old chart' in quotes makes me think that you don't believe me :mrgreen:
     
    #4 wilco, Jun 27, 2005
  5. HYACK

    HYACK New Member

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    To the contrary, sir..

    I have to respect that ol' chart, indeed (Old school is cool) :mrgreen:
     
    #5 HYACK, Jun 27, 2005
  6. ~sparky~

    ~sparky~ New Member

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    thanks... there's one complication i failed to mention. the terminals on the amp to connect the power, ground and remote wirign are very small and close together. if i use larger gauge wire, how do i terminate / connect the wire into connectors that will fit?

    thanks.
     
    #6 ~sparky~, Jun 27, 2005
  7. wilco

    wilco New Member

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    Well, like I posted above, if it's a relatively short run 14ga will be fine. Here is another chart I got from rec.audio.car a while back.

    The current is actual, not the fuse value, and the numbers in the body of the chart are AWG.
     
    #7 wilco, Jun 28, 2005
  8. wilco

    wilco New Member

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    OH yeah, I forgot about your terminal/connection question...

    If you are going to change the wire, and the length is under ten feet, you could go with 10ga and still have a voltage drop <.5V (which is good). If the length is over 10 feet, go with 8ga.

    You should be able to get connectors from any electronics or automotive store that will accept 10ga wire and still have the same size connection to the amp's terminals. If you go to 8ga, you may need to get the connectors from a car audio place, but they do exist.
     
    #8 wilco, Jun 28, 2005
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