I'm going to write this assuming you're in the USA with standard 120/240v residential service. The voltage levels are usually between 110-125/220-250v which is why they can be referred to as 110v, 115v, 220v, 240v, etc.
I am getting into more serious LTC mining, and am building multiple rigs.
Recently, I had 4, 20 amp breakers installed for 110v outlets. After (finally) getting a kill-a-watt, I've determined that the amperage draw from these rigs is immense - about 9 amps with 5 GPUs. So I could run 8 rigs. However, I'd like to run more than that - preferably 12 or 14. Additionally, my power box is rated at 200 amps, which would worry me if I tried to install more breakers/110V circuits.
Enter the idea of 220 volts. I've seen videos/pictures of people running Bitcoin rigs off of 220V, which allows them to run a lot more systems off of one circuit (one such person was running something like 5 rigs off of one 220v dryer outlet).
So my questions about 220V....
1. Wiring wise, what would I have to change if I wanted to run 220V? Would I have to have everything changed out - breakers, wiring, and outlets, or just breakers and outlets?
Just breakers and outlets. You need to switch your breakers to double pole breakers (the same kind used for electric ranges, clothes dryers, and central air systems), and you need to switch your receptacles to ones used for 240v. You also need to put a piece of red or black electrical tape around the white (neutral) cable for each of the circuits you convert. (for safety- so anyone working on the circuit knows that the white wire is no longer a neutral)
I'd recommend using NEMA 6-15R or 6-20R receptacles. You can use other types like ones designed for locking plugs and the kind used for clothes dryers (NEMA 14) but 6-15 and 6-20 are probably best for this job.
Example breaker (you *need* to buy the correct type for your load center):
http://www.homedepot.com/p/t/100074746?catalogId=10053Example receptacle (NEMA 6-20R; rated for 20A at 250V):
http://www.amazon.com/Leviton-5822-W-Receptacle-Commercial-Grounding/dp/B000U3I1S0NEMA 6-15 is rated for 15amps, and 6-20 is rated for 20amps. You can plug a 6-15 plug into a 6-20 receptacle which is why I recommend using 6-20 receptacles if you have at least 12 gauge wires. (which I assume you do, since your circuits already have 20a breakers)
2. My PSUs are rated for up to 264v (Seasonic 1250W). I assume these will work, correct? I will just need an adapter to go from the 220v outlet/power strip to the PSU, right?
Yep. Actually, you can even cut the plug off your current cables and add your own 250v plug. I would use a NEMA 6-15 plug:
http://www.homedepot.com/p/t/100206376?catalogId=100533. How stupid, crazy, or risky is this idea? Mind you, the wiring and electrical installation would NOT be done by me. I have a professional electrician that has done work for me, and installed the 20a breakers.
Not at all. This is perfectly safe and in compliance with the National Electrical Code. You would probably be fine doing the work yourself, considering you have the technical ability to set up a mining farm. (the ability to legally do the work yourself depends on your local building codes, though)
I temporarily did this to run my mining farm from a single 15-amp circuit while I set up a more permanent solution. (currently 4x 20A 120V circuits... I'm just mining with FPGAs though.
)
Or are there any other suggestions for running more rigs on less amperage?
P=V*I. (Power, Voltage, Current) The only way to get more power and use a set amount of current is to increase the voltage.
So no, switching your 120v circuits to 240v is the best option.
Thank you!
Good luck! (and be safe!)