Why does everyone over think and try to over-engineer..
It is SOOOOOOO SIMPLE cheap and effective to just do this...
And All 8x S9's Running just fine...Mission accomplished
NOTICE NO PDU NO PLUGS..3x PSU's are connected straight to 220V 30amp line using bare wire and marrets & electric tape.
Serious code violation, and DANGEROUS.
Not a real good idea even if you KNOW what you are doing.
There is a REASON the NEC is very much ANTI-SPLICE and has been so for a while - as I recall even the old-style "wire nut splice" method is depreciated for new construction in recent versions of the Code, and it's never been considered a "best practice".
Keep in mind that the NEC came about to prevent FIRES, and who is behind it.