Hello to all. I look at some similar topics in the forum but i could not find the answer i need it, so sorry if my question is already answered.
I have evga 1300 g2 PSU and i want to connect 7 GPUs to it. Evga PSU comes with 4 x 8pin vga cables and 2 x 8 pin + 6 pin. I have bought some evga GTX 1070 sc also and they come with cable from 2 x 6 pin to 1 x 8 pin.

My question is if the idea on the picture above is save if we consider i want to connect also MB, SSD and CPU?

Thank You :)

1 big psu is not better than 2 smaller psu's.  You're better off to have 2 smaller psu's in this case as it will make it easier to manage.  As Chris21010 said though, your situation here is how much power do you need.  You have 7 cards, that need 150 watts each (1050), your PSU can handle those, but you also need to power the risers, at 75 watts each (525), give or take, and the motherboard (you haven't said your board and chip so let's assume 125 watts).  You're already over the wattage required.  The only way the psu will do, is if you have an asus x99 board with 7 pcie slots and you're using a xeon, and have slot extenders instead of risers.  Even then you'll be pushing it at 1200 watts. That's my take on it.  I'd say if QuintLeo has anything to say, he'd be the real one to listen to as he knows way more than I.  I think you'd be better off with 2 750's.
 
I know you can undervolt the cards to save some power, but still, I think you'd be pushing it.

The only question for me is if this connection (2 x 6 pin coming from two different ports using adapter are converted to 1x8 pin) is safe? The power usage i will measure with 6 cards and if there is enough space i will add 7th if this connection is ok. I already have 1 rig with 6 gtx 1070 running ok with 1200 W PSU. I always set max power limit to 95% to the cards and the whole system never used more then 950-1000 W. For this rig I will use the same MB, SSD, RAM, CPU. The only differences is that instead of 6 gtx 1070 , I want to connect 5 gtx 1070 (evga SC) and 2 gtx 1070 ti (zotac mini) (they are all with 1x8pin ).

Chris21010
nearly every GPU sold today comes with a 2x 6pin to 8pin adaptor. if this wasn't safe they wouldn't sell them.

Good enough for me... thanks

savs90
The only question for me is if this connection (2 x 6 pin coming from two different ports using adapter are converted to 1x8 pin) is safe? 

 Yes.
 All of the EVGA G2 line are "single rail" designs where all of the 12VDC comes from the SAME source.
If the power supply was a MULTI-RAIL design, this could be problematic - but that has gotten very RARE on high power ATX power supplies, and I don't remember ever seeing one at the 1000+ watt level that was multi-rail out of a REPUTABLE company.
 
 Most GTX 1070 cards have a TDP of either 151 watts or 180 watts.
 Even at 100%, it should be safe to run 7 x 150 and an EFFICIENT motherboard/CPU/etc setup from a G2 1300, though 95% is better on efficiency.
 
 7 of the 180 watt TDP cards (examples include the EVGA FTW, Gigabyte Windforce) would be VERY marginal at best.
 Most if not all of those cards have *2* power connectors though, normally an 8-pin AND a 6-pin.
 
 This power total INCLUDES the power the card draws out of the riser.
 
 There is at least one card out there (MSI Armor Gaming X or something like that) with a 240 watt TDP and 2 x 8-pin power connectors.
 It seems to be almost impossible to push the card to that high of a power level though short of Liquid Nitrogen cooling - even the 1080 version of the same card has the SAME default TDP and I've never gotten mine to eat more than about 220 watts.