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how much power can a molex chain handle?

Discussion in 'General Hardware' started by kajson, May 30, 2012.

  1. kajson

    kajson

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    Hello, I"m finishing up my new build, I'm on to the cable management now, I'm using a modular 600w silent pro gold PSU, which comes with only one double molex plug cable,

    Now my question is, will it handle in a chain:

    1. the powerup button and usbports on top of my CM 690 II
    2. the front fan being the 140mm fan
    3. dvd burner (sata)
    4. http://www.raidsonic.de/en/products/details.php?we_objectID=7499


    I could put a different sata power cable to the dvd player if you dont think the molex cable will be able to deliver sufficient power.
    a lot of devices on the cardreader device are powered by their own usb cables and im not using the esata and the audio part on that device.

    tnx in advance
     
  2. btarunr

    btarunr Editor & Senior Moderator Staff Member

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    It depends on how much the 12V rail it's attached to can deliver. Its physical capacity is usually printed on the bare wires.
     
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  3. Frick

    Frick Fishfaced Nincompoop

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    There's only one 12V rail anyway so in theory you could pull 48A on that and 25A on the 5V rail (unless the wires melt first). So yes, it'll be fine. :)

    [​IMG]
     
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  4. kajson

    kajson

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    I was just worried if the one molex cable could handle the power, it says something like " 9j awm 1007 18 awg 300v" on the cable.

    I cant get any useful info out of those numbers.

    edited system specs :)
     
    Last edited: May 30, 2012
  5. n-ster

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    I think it's something like 120+ Watts (12V 11A), you should be fine

    only time I've seen a problem is like with 15 delta fans in chain
     
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  6. JrRacinFan

    JrRacinFan Served 5k and counting ...

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    A single 18 gauge for how small the run of wire will be, would probably be close to 8a.
     
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  7. Frick

    Frick Fishfaced Nincompoop

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    This site says it can do 16A on short wires but that's probably too much.
     
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  8. n-ster

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    lol yea I wouldn't try 16A o.o I stay at 10 and below
     
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  9. FordGT90Concept

    FordGT90Concept "I go fast!1!11!1!"

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    Wikipedia says 14 amps at 90 degrees celcius (which is very hot). Using that figure, a single 18 AWG wire should be able to handle 168 watts at 12 volts.


    If you reduce that to 2.3 amps given here: http://www.powerstream.com/Wire_Size.htm

    27.6 watts 12v and 11.5 watts 5v


    Used calculator here: http://www.sengpielaudio.com/calculator-ohmslaw.htm


    Edit: I'm going to check the Pocket Ref and see what it says.

    18.00 amp @ 86-95F
    16.38 amp @ 96-104F
    15.66 amp @ 105-113F
    14.76 amp @ 114-122F
    13.68 amp @ 123-131F
    12.78 amp @ 132-140F
    10.44 amp @ 141-158F
    7.38 amp @ 159-176F

    As a general guideline, 18 AWG should not exceed 10 amps (120 watts @ 12v).


    Edit: Keep in mind that the majority of 12V power is dedicated to the CPU (via EPS12V and P4 connectors) and GPU(via PCI Express 6- and 8-pin connectors).
     
    Last edited: May 30, 2012
    kajson says thanks.
    Crunching for Team TPU
  10. de.das.dude

    de.das.dude Pro Indian Modder

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    it will be fine. but that wire may get hot.
     

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