Question about ATX PSU

[turtle83]

Say i need to power a 12V device using ATX PSU. And i have doubts that the wire will be able to support the current needed (i am sure that the PSU/rail can). Can i join in multiple +12v and ground wires into bundles to distribute resistance?

i.e. strip 2 yellow cables, and join them both to the +12v connector on my device, and 2 black cables to the ground lead on the device.

Which of following is true.

1. You dont know what ur talking abt ur gonna burn your house.
2. Its fine as long as you bundle up wires from the same bunch of cables. (Usually PSU has like 4 or 5 bundles of cables coming out)
3. Its fine as long as you bundle up wires from same ATX rail.
4. Doesn't matter. You can join up any wire from anywhere as long as its same color.

In other words, is it safe to join all the black cables to one place, and all the yellow cables to another place and distribute from there without needed any capacitors, resistors, etc ...

[crazyates]

1) and 3) are true.

What are you trying to power that uses more than the ATX standard?  A 6-pin is rated for 75W, and an 8-pin is rated for 150W. The only difference between the two? A 6-pin has 3x 12V lines, and 3 grounds. A 8-pin has 3x 12V lines, and 5 grounds.

So if you're using an 8 pin, all 12A are split over 3 of the 8 cables, giving you 4+A on each wire. They can handle that no problem, so what are you doing that pulls 4+A per wire?

[FlappySocks]

Try this:
http://www.youtube.com/watch?v=z2oSFpKh_Uw

[razorfishsl]

1) and 3) are true.

What are you trying to power that uses more than the ATX standard?  A 6-pin is rated for 75W, and an 8-pin is rated for 150W. The only difference between the two? A 6-pin has 3x 12V lines, and 3 grounds. A 8-pin has 3x 12V lines, and 5 grounds.

So if you're using an 8 pin, all 12A are split over 3 of the 8 cables, giving you 4+A on each wire. They can handle that no problem, so what are you doing that pulls 4+A per wire?

Actually only 1 is  reliably true......
Some ATX power supplies split out the 12V into multiple circuits but only one power section, whilst other have a separate switching & inductor sections. (only reliable way is to open it up and see how the cables are clumped, or you could load the PSU up on one cable and measure each 12v section to see if they are separate)

If they are internally clumped together, then go ahead... an alternative is this fuck fest....

The advantages are:

• I can re-connect the 'old' wires internally and sell the supply.
• I can drop a couple of Ohm's, because ATX PSU connectors are only crimped not soldered
• ATX cables are made from shite metal mixes, to save money

Ensure you use 'mains' single core 'Twin & Earth", 6-12A  to wire into the 12V, that way at 12V it is good to  120A~240A and since it is pure copper the resistance is about 20R/km@1mm2

If you REALLY have a fetish about resistance then take it to 2.5MM2 it will be about 8R/km

That SHIT they supply with ATX PSU is a metal mix and it is tin plated.

[turtle83]

1) and 3) are true.

What are you trying to power that uses more than the ATX standard?  A 6-pin is rated for 75W, and an 8-pin is rated for 150W. The only difference between the two? A 6-pin has 3x 12V lines, and 3 grounds. A 8-pin has 3x 12V lines, and 5 grounds.

So if you're using an 8 pin, all 12A are split over 3 of the 8 cables, giving you 4+A on each wire. They can handle that no problem, so what are you doing that pulls 4+A per wire?

Say if I want to power 9 50W devices which need 12v. My PSU has a single 12v/40A rail. In this case the 6/8 pin connectors are not enough since i need 9 of them... I would need to use up all the cables...

Just me procrastinating for future use, when i get some klondike boards to mine with. The options are either use ATX PSU that way I can run raspberry pi and usb hubs off the 5v supply also. OR get a 12v only power supply (ive seen many 12V 50A supplies on the net), and figure out the 5V separately.

[turtle83]

Try this:
http://www.youtube.com/watch?v=z2oSFpKh_Uw

According to this 4. is true. since all he does is bundle up wires of same color into a single connector. He specifically states that bundling up wires from different rails is fine.

4. Doesn't matter. You can join up any wire from anywhere as long as its same color.

[ssateneth]

The 4 pin molex spec says 11 amps per pin. This is 132 watts from a single 12v wire. You could pull 375 watts from a 6 pin pci-e and still be in spec for the wires if they are the same gauge (they should). Knowing me, I would do #4, so long as they are all from the same power supply.

[crazyates]

You're gonna pull 11A on a 18ga wire?! Hell no, not me. You're asking to get one of your connectors burnt and/or melted into a steaming shithole.

[tom_o]

The 4 pin molex spec says 11 amps per pin. This is 132 watts from a single 12v wire. You could pull 375 watts from a 6 pin pci-e and still be in spec for the wires if they are the same gauge (they should). Knowing me, I would do #4, so long as they are all from the same power supply.

Per pin is different from per WIRE. That's just what the connector itself can supposedly handle!