Currently I have a 30 amp breaker, 220 v and a 30 amp PDU. I run 2 ASIC machines at 5000 watts which is less then the 80% rule of 5280 watts (220 * 30 * 0.8). If I wanted to buy another ASIC miner, would I have to get a new breaker installed and buy another PDU? It seems on YouTube many people have tons of ASIC Miners plugged into one PDU (compared to my two), but I could be wrong.
Any advice is greatly appreciated! Happy mining 
It all depends on what you are running. I have a s7LN which draws around 900w so I could run 5 of them on a 240v 30amp circuit. With an s9 with an OS like hive or brains OS installed you could have a few running one 1 PDU.
Ok thank you. Just to clarify, every time I hit hit my 80% (5280 watts) whether that is 1 powerful ASIC miner or 10 lower power more efficient ones, I would need a new breaker and PDU to expand?
yes once you max out at 80% you will need another 240v 30 amp circuit and PDU set up.
The 80% rule gets misapplied from time to time. For branch circuits the wiring has to be 125% of the load ampacity and the CB trip setting is for 125% of the continuous load in order to allow for in rush and prevent nuisance tripping.
The 80% rule is a UL rule that prevents you from overheating the wiring downstream of the CB and typically applies to conductors larger than #10. This is because the NEC states the exact protection for wire sizes #10 and below. The NEC specifies a 30 amp overcurrent protection device for #10 wire because of it’s use in residential applications. 2500/220 = 11.4 amps per miner, so two is the max for this circuit with a 30 amp CB.
I went into that detail because you would not necessarily have to add another circuit. If your PDU was rated higher and you used #8 (or larger) wire you could just increase the size of the breaker. This is something to run past your electrician and could save money compared to pulling a new circuit. Above a #10 you would use a larger breaker that would trip at 125% of the continuous load and wire sized at 125% of your continuous load.
Miners would be a continuous load because they run for more than 3 hours at a time. If you had cooling fan or electrically operated damper (let’s say 5 amps) for heat control that ran intermittently you would only size your conductor for 1.25*(miner total current @11.4 amps per miner) + 5. The NEC says 125% of continuous + 100% of noncontinuous load.
The 80% is an NEC rule for continuous load so for mining you are limited to the 24amps max load. Now the 125% for the wiring only comes into real effect with noncontiguous load which you can go up to the full 30aps. This 125% is already factored in to the wiring. Hence why 10 gauge is 30amps 8 gauge is 40amps etc…