Using a power supply as a 12v source.

[Ragecalm01]

I am using a 750w Single 12v rail power supply as a 12v source. I have isolated all +12v circuits from their respective plugs(pci-e/molex/IDE, etc.). I will use all these to make a 12+ terminal to power 3 speakers and an Android Auto headunit. 

My Question is. What can i do to create or tap into as a ground terminal for these 12v items(Head Unit, a small 300w Subwoofer Amp.) I may also try to tap into other rails for USB charging ports. Will that also require a ground?

Edited April 26 by Ragecalm01

[OhioYJ]

10 minutes ago, Ragecalm01 said:

What can i do to create or tap into as a ground terminal for these 12v items?

The same ground the 12v+ uses?

[Ragecalm01]

2 minutes ago, OhioYJ said:

The same ground the 12v+ uses?

The ground wire going into the power supply from the wall outlet? 

[Needfuldoer]

Just now, Ragecalm01 said:

The ground wire going into the power supply from the wall outlet? 

It connects there eventually.

 

The black wires on the low voltage side are all ground. Just tie those together. Use at least as many of them as you have on the +12v side so things don't get melt-y.

[Ragecalm01]

3 minutes ago, Needfuldoer said:

It connects there eventually.

 

The black wires on the low voltage side are all ground. Just tie those together. Use at least as many of them as you have on the +12v side so things don't get melt-y.

They are all uniform white in color. I cant tell whats what except with this diagram. The eye connectors are all my +12v. I can? tap into the ground wire from the wall outlet as a ground? 

[OhioYJ]

Those ones labeled COM.

 

It appears you cut the ends off of evey thing though, so may a multi meter, would be the best way to double check your work here.

[Ragecalm01]

3 minutes ago, OhioYJ said:

Those ones labeled COM.

 

It appears you cut the ends off of evey thing though, so may a multi meter, would be the best way to double check your work here.

So COM is def a ground? I wasnt sure on that one. I still know the pinouts but i do have a multimeter handy. Going to wire up the on switch for jumping the wires on the 24 pin. Thanks for the help!

[Needfuldoer]

12 minutes ago, Ragecalm01 said:

So COM is def a ground?

Yes. COM means ground in this context.

[Blue4130]

1 hour ago, Ragecalm01 said:

I may also try to tap into other rails for USB charging ports. Will that also require a ground?

 

Yes, USB also need grounding.

[mariushm]

COM is short for common, ground. 

 

To turn on the power supply, you need to connect the PS_ON pin to ground, any ground.

 

You shouldn't have damaged your power supply connectors. You could have bought pci-e extension cables and cut them in half to get access to the wires, for example : https://www.amazon.com/Pin-PCI-Power-Cable-Include/dp/B08ZRX37GF/