Do you mean extension for power cord to psu or extensions for psu to gpu cards?
If main power either buy a longer cord or buy an extension cord thst can handle the power draw. In this case at least 750w but i would go higher. If 110v power then a 15amp cord. If 208-240v then a 7.5-10amp cord.
If you mean for psu to gpu then you can get extensions but for 4 gpus should be needed. i run 6x13 gpus off the psu depending on size.
Just be sure to get good quality wire and made ones.
Risers come with 2-3 ft usb cable so shouldnt need extension there.
From the wall to PSU. Can't find anything that plugs directly to the wall (UK) without an adapter. I'll be powering two 700watt psu (assuming thats what I need to power those 5 gpu system)
PS: sorry if all of these is a little bit confusing as I'm very new to mining and learning bit by bit everyday.
Thank you
