All Grounds the Same?

[MorfiusX]

I am in the middle of modding my PSU. Included is custom length wiring. The molex connectors (for drives) have 4 wire. 12v, 5v, and 2 grounds.

Are all the black wires the same ground?

Or, is one spacifically for 12v and one for 5v?

I don't want to fry anything when I start this thing back up?

If I were to accidentally switch the two black wires, would I have any begative effect? Or are the all just a common ground?

 

[awdark]

Based on my recent experimentation, all grounds are the same. If you want to play it safe, connect it to a multimeter and check the voltages before plugging it in.

 

[computerpro3]

yep all are the same.

 

[xonik]

Yes, they're the same. The reason why there are multiple ground wires is to properly handle heavy current draws by individual voltage rails. If both the 5 and the 12 volt lines were drawing lots of current, a single 16 or 18 gauge wire for ground might be inadequate. Therefore, the power lines have separate grounds for each voltage line.

 

[MorfiusX]

Well, I have got everything back together. I am not 100% sure that I didn't switch up a couple same-voltage wires. But, everything works 100% correctly. Thanks.

 

[FLECOM]

if you look inside your psu you will see every single black wire goes to the same place... as was said before, the only reason you have more than one in any given connector is for load reasons

 

[gee]

if you look inside your psu you will see every single black wire goes to the same place... as was said before, the only reason you have more than one in any given connector is for load reasons

And the funny thing is that when you mount your metal HD or CDROM in a metal case, screw your motherboard down through metal fasteners to your metal case, etc... the great majority of the ground return current to the power supply goes through your case, not your power supply ground leads! And if you mount a hard drive in an isolated holder (eg the ones in a Sonata case) the ATA cable will probably carry quite a significant part of the ground current.

Computers are a grounding nightmare... I'm very much glad I don't design computer hardware for a living.

 

[FLECOM]

And the funny thing is that when you mount your metal HD or CDROM in a metal case, screw your motherboard down through metal fasteners to your metal case, etc... the great majority of the ground return current to the power supply goes through your case, not your power supply ground leads!

thats normal, and not really a bad thing, its supposed to happen... if you look at the inside of your PSU the ground lead from the power cord goes straight to the psu chassis

And if you mount a hard drive in an isolated holder (eg the ones in a Sonata case) the ATA cable will probably carry quite a significant part of the ground current.

no... trust me on this one it dosent work that way

if it did my scsi cable would be half-melted, since im sure my 15k pulls enough current to melt those tiny wires 80x over

Computers are a grounding nightmare... I'm very much glad I don't design computer hardware for a living.

yes and no, ground isnt that huge an issue in pc's or else every pc would have to be completely custom made etc no interchangeable components...

just certain things are assumed... your ground is ok, and matches chassis ground...

which is true 99% of the time, and the other unique 1% of the time, its usually still ok...

ex acrylic cases dont have any ground return through the case obviously