Do i need two power supplies for my rig?

[ninjagod]

Ive seen almost every rig have two power packs/supplies.

Can i get away with just one?

[MATHReX]

Well, what is the model of your GPU and how many are there in one rig? It all depends on the power consumption of the complete rig.

[ZenFr]

Ive seen almost every rig have two power packs/supplies.

Can i get away with just one?

No, absolutely not.
Only AMD GPUs have to have 2 PSUs because they eat a lot of Watt.
With an nVidia RIG, even a 6 x 1070 GPU, you can have only one PSU.

[jmigdlc99]

Its best if you plan ahead and get a PSU that can handle a large load, for example a SERVER PSU. You have to be ready for a significant increase in noise but server PSUs are of platinum grade (better power efficiency) and are cheaper than consumer PSUs.

[Set Ready Go]

Fist and foremost it depends what gpus you are gonna run  in your rig and how many.

6 GPU rig examples:

Example 1:

6x Rx 470 intro with 6x 6pin pci-express risers. Two evga supernova 750 G3 power supplys woyld be enough. Psus havet 6+6 8 pin pci-express cables.

 Example 2:

6x Rx 460 2 gb, NO 6 pin.
One evga supernova 750 G3 with 6 pin risers would be enough.

Conclusion is that gpus matters and how many Connectors your psu havet. 

[Undefined31415]

Ive seen almost every rig have two power packs/supplies.

Can i get away with just one?

That depends on what PSU or which pair of PSUs you plan on getting, along with all of the components that your system will be composed of.

Considering the other threads you've made, you have no idea what your system is going to look like, so it's too early to answer this question. I suggest that you learn the general process of assembling a desktop PC prior to messing around with a GPU mining rig.

[Vann]

It depends on how many cards you plan having in the rig and how many power connectors each cards requires. The total watts is only one factor. Another factor is number of PCI-E power connectors you need for the GPU's. If the PSU doesn't have all the VGA power connectors you need for the cards, you may need to use a larger PSU with more VGA connectors or a secondary PSU to have enough VGA power connectors for all the cards. Another consideration is when going with a 1500 W or more PSU, two smaller PSU's are cheaper than a single larger PSU.

[IamRune]

I've got 8 rigs of (6) 480 RX 8GB running perfectly fine on a 1300 G2 EVGA Power Supply.  Never had any issues.