GPU miner here, been running dual PSUs for last decade. My typical rig consists of one motherboard, 6 or 8 cards, two PSUs 650-850W each, for total of 1100-1200W per rig. They are running for years on end, without any reboots.
I presume you just speaking from what you heard, not real experience?
I agree, that running two PSUs on one electrical device (like one Apollo or one GPU) is a no no. But don't extrapolate that to "One should NEVER try to run ANY sort of PSU's in parallel" (your quote), because that's BS.
Are you running your PSUs in parallel or in series though? It seems you have one set of things powered by one and another set of things powering separate items. The current only flows through one path in a series setup.
Exactly, I Previously had 2 gpu-mining rigs, one running 12 cards the other with 5 cards. Having 2 power supplies is fine as long as you have it set up correctly. First you’ll need a piece of hardware like add2psu which connects the 2nd-slave psu to the master, you can also use a paper clip if you’re willing to take that risk. The main thing is
to connect the peripherals to 1 psu and not both. For example for mining rigs the gpu riser and gpu will be connected to 1 psu so both pull from the same power source. You should never connect the riser to one and the gpu on it to another, that would cause problems. So I’m terms of the Apollo don’t plug 2 separate power suppliers into 1 machine..
My old rig ran 24/7 for around 3 years straight never had any serious problems or fire related incidents, you just need to know what you’re doing