I am not an electrician, but an end user.
I am planning to build a very powerful server for running LLMs. It will have many GPUs and can realistically hit a 1500 watt sustained load. The PSU in my computer can handle 240v but I do not have access to a 240v circuit.
My question is whether it is a good idea to somehow balance the load between 2 or 3 120v circuits. If so, what are some methods to safely do this?
You’re equating 120+120 = 240 and while that works in math, it does not work in alternating current voltage.
I am also an end user. What you’re wanting to do is dangerous and will either get you killed or leave your expensive servers a pile of slag. If you really have the time, money, and knowledge to run a server bank with “many gpus”, then get a real electrician to enable you to even install it correctly.
Honestly your question makes me question your preparedness. I’d consider more research if I were you.