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  • power cable

    I want to power 2 amps for my speakers and 1 computer, should I just be running one 0 Gauge wire back to my trunk, or a few 2 or 4 Gauge wires.... thanks!

  • #2
    i run smaller wires because it is easier to connect fuses on smaller wire. I think if its connected and fused properly it shouldn't make a difference.
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    • #3
      Originally posted by RussellB
      I want to power 2 amps for my speakers and 1 computer, should I just be running one 0 Gauge wire back to my trunk, or a few 2 or 4 Gauge wires.... thanks!
      well it comes down to power used and the length of the run... the computer is nill... figure on about 10 amps there... then add the fuses off the amps... I run 8 gauge for my RF P4004 which has two 30 amp fuses and my power supply has a 10 amp... so I run 80amp at the battery and about 17 feet of 8 gauge...

      I would never believe that you could have too big a wire, but cost is the limiting factor...
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      • #4
        wow, you guys are talking over my head

        So if I run 1x4G wire ? Or 2x4G wire?

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        • #5
          Originally posted by RussellB
          wow, you guys are talking over my head

          So if I run 1x4G wire ? Or 2x4G wire?
          If you can, run 1 big a$$ wire from the battery to the back and connect to a distribution block. From there run smaller wires (size depend on device's power consumption) to connecting devices (amps, PSU, Inverter...). Usually the distribution block has fuses to the connecting terminals.
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          • #6
            I think the point everyone is trying to get across is that the choice is really up to you. Some folks prefer several smaller wires, and some prefer one big wire connected to a distrobution block. As long as you properly connect and fuse whatever you use, the choice is yours. I usually happen to prefer one large wire connected to a fused distrobution block, but that's just my preference.

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            • #7
              4G should be big enough, you can run 1 4ga from the battery to a distro box and split from there to 8ga.
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              • #8
                Originally posted by mgithens
                well it comes down to power used and the length of the run... the computer is nill... figure on about 10 amps there... then add the fuses off the amps... I run 8 gauge for my RF P4004 which has two 30 amp fuses and my power supply has a 10 amp... so I run 80amp at the battery and about 17 feet of 8 gauge...

                I would never believe that you could have too big a wire, but cost is the limiting factor...
                Not doubting you, but 80 amps seems to be a lot of current for a 17' run of 8awg cable! If that were my car, I'd run at least 4awg. From a quick calculation, you have a 1.5V drop across that line (from http://www.powerstream.com/Wire_Size.htm ). At 12-14v, that's a lot of power dissipated. Even a quick glance at the table at http://www.engineeringtoolbox.com/am...ge-33_730.html supports the notion that a 4awg cable seems to be a safe option. I'm not knocking your setup by any means, but 80amps over 17 feet of 8 gauge raises safety concerns for me.

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                • #9
                  but that's an 80 amp fuse... on a normal day I am making like 50 watts total with the amp and then about 50 watts with the computer... both are regulated and both can handle a 12.9volt load... (12.9 is based on 14.4 from alternator and 1.5 drop - according to your math)... I am NEVER going to see peak loads on my system... because A) my amp is 60amp fuse... and B) my computer is 10amp fuse... and finally C) they will NEVER both be maxed... keep in mind that powerstream is in the business to make money... they'll also tell you there is a difference between $8/ft wire and $2/ft wire...

                  I ran my previous setup off a 10ga... that was for both the 2x50 amp and the computer... there are TOO many factors... but believe me that an 8 gauge is plenty for a 4x50 amp and a 90watt MAX computer...
                  EPIA SP13000, 512 DDR400, Seagate 300GB, Belkin PCI 802.11g w/external antenna, Holux GM-210 GPS, XM Direct w/ serial, Dlink FM, Opus 120 p\s, Rockford P4004 amp, Xenarc 7" VGA touchscreen custom mounted in double din spot -- see pics and write up here!!

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                  • #10
                    So what fuse do you have to protect your 8ga cable? I was under the impression taht you had an 80A fuse on the 8awg... In which case, you could short the cable, and have the cable transporting more power than it is safe for yet less than enough for the fuse to blow. Say you draw 75A, less than fused, yet more than what is safe for that cable. So you begin to slowly melt the cable and have a possible fire hazard on your hands.

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                    • #11
                      well based on your assumptions of a perfectly balanced short, then every single wire is technically undersized... you are betting that the wire will short at exactly the necessary resistance to not blow the fuse, but heat the wire... you can't design that way... I could put a 2awg in there and it would still run the risk because now you just bias the location of the heat at the short... the energy will have to be disapated somewhere - it will be the wire or the location of the short... the wire or short will get hot... either way there will be a fire... solution = only run super low amperage devices??

                      fuses aren't to protect against EVERY scenario, they are for the nastier side of things.. the quick and high sparking issues...
                      EPIA SP13000, 512 DDR400, Seagate 300GB, Belkin PCI 802.11g w/external antenna, Holux GM-210 GPS, XM Direct w/ serial, Dlink FM, Opus 120 p\s, Rockford P4004 amp, Xenarc 7" VGA touchscreen custom mounted in double din spot -- see pics and write up here!!

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                      • #12
                        Originally posted by mgithens
                        well based on your assumptions of a perfectly balanced short, then every single wire is technically undersized...
                        Not really. If you fused your 8awg at 40A, then it'd likely be safe. I have a 15' run of 2awg, fused to 100A. This is safe, since the cable can supply 100A safely, and the fuse will cut off current should it get much higher than what's safe. It wouldn't make a whole lot of sense to put a 300A fuse on that line, since the cable will melt and could start afire below the fuse rating. And actually, most fuses are designed to sustain a given amount of time above the rating (e.g. the 300A fuse may pass 350A for 5 minutes and not blow).

                        All I'm saying is that you should have a fuse to protect the cable. A 80A fuse does not really protect a 17' run of 8awg cable very well. I'm just worried about the safety of your setup... Nobody wants to see anyone's car start fire!

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                        • #13
                          I have some spare fuses... just for giggles, I'll pull my hot lead and touch it to a painted body panel (like in my spare tire area)... resistance will be initially high due to the paint, but within a moment it will be through the paint (due to heat at the short) and the resistance will be well below the 80amp requirement...

                          thoughts??
                          EPIA SP13000, 512 DDR400, Seagate 300GB, Belkin PCI 802.11g w/external antenna, Holux GM-210 GPS, XM Direct w/ serial, Dlink FM, Opus 120 p\s, Rockford P4004 amp, Xenarc 7" VGA touchscreen custom mounted in double din spot -- see pics and write up here!!

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