the danger is small if you find correct holes and keep it from shorting.


but frankly  just buy this


http://www.ebay.com/itm/JUMP-START-PSU-EPS-ATX-24-PIN-24p-POWER-SUPPLY-JUMPER-ON-OFF-switch-cable-50cm-/141416477255?pt=US_Power_Cables_Connectors&hash=item20ed143247


or one of these

http://www.ebay.com/itm/JUMP-START-ON-OFF-ATX-20-PIN-POWER-SUPPLY-WITHOUT-A-MOTHERBOARD-MADE-IN-USA-/261256302157?pt=US_Power_Cables_Connectors&hash=item3cd416ce4d


having the switch means something on a lot of psu's  turning it off via the switch in the device above is better then turning it off via the switch on the back of the psu.