Quote from: betajuice on April 11, 2021, 07:20:44 PM

This question has been asked a couple times with variations and I haven't quite got an answer so I'm posting this here.

I found a small shop to use for mining, aiming for about 150kw total 24/7 power draw. I'm discussing with TDU and electrician about setup but neither of them are very helpful in giving advice for what I need. Their attitude is mostly just like "just tell us what you need and we'll do it". The shop has a small 1 phase 200 amp panel, but they are willing to make the upgrades.

From my research, it seems the question of 3-phase vs 1-phase delivery just comes down to cost. All mining hardware uses 1 phase but still many people seem to recommend to go with 3 phase because of reduced delivery costs. I'm not 100% sure the reason for this, so that is part of my question. Secondly, I might be able to take the panel and any other electrical equipment from the shop with me to later expand, so if 3 phase isn't strictly neccesary, maybe it is a good investment anyways?

Anyway my main question here is, should I give the TDU a load sheet requesting 3-phase power or just 1-phase? Any advice on this is appreciated because I am really unsure.

Thanks.

First I want to say that although I'm no electrician but end up with problems like this often enough in different applications. What country are you in, and what are the voltages at your mains legs? I ask because I always consider 220-240VAC as being "2 phase - more properly two single phase legs" - I have a shop with three phase and we have some equipment that is larger that does indeed need three phase. Not mining equipment mind you, but compressors and steam generators. So without three phase, we'd (my shop) be doing some expensive electric motor upgrades - we can't do like most (very small) miners and go either one or two legs of hot. Again I consider each leg of 11-120VAC a phase. So because you are just going to mining, I'm thinking it would be cheaper to go 220V - 2 legs of 1 phase 110-120VAC than just 1 phase if you are indeed 1 phase - and that may be the case in some places, but very few as far as I know. My feeling is that you are in the US and really have 2 legs of 110-120VAC (2 phase in my mind, they are 180 degrees out of phase, thus I say two phase) along with a neutral and ground coming in from the grid. Voltage [V] x Amperage = Watts [P -Power in watts], or P/V=A, so Amps (current) is lower by half for each leg of 110VAC. se V=IR Ohms law brings in the resistance term, you would have lower current draw on each leg, thus lower resistance, getting you more efficient, safer wiring, and saving on electricity cost marginally if it's set up properly (and inspected by a real electrician etc). Lower Amp draw running one phase per leg (phase) of your power supplies, splitting the load between two conductors. Now if you have three phase you can send those phases for different loads more efficiently and ultimately end up being able to distribute loads better, but that is really a matter for future expansion.

More directly to your question - should you go 3 phase if you can? If money is no worry, three phase allows you to run larger equipment like welders and other fun things you may want in the future, and split loads in creative ways.