Crossy

It's not been 4 Baht per unit for a good while unless you are a very low user. https://www.pea.co.th/en/electricity-tariffs Note that the numbers on the above link do not include the FT (fuel tariff) which is currently 0.3972 Baht/kWh I did pick the wrong tariff for the calculator but even with the correct tariff you're looking at about 11,300 Baht per month and that's only going to go up.

So, viruses and vaccines now follow politics? I suggest the report linked in the OP is a load of dingo's kidneys (c)Douglas Adams https://en.wikipedia.org/wiki/Correlation_does_not_imply_causation

I think you are under-estimating your energy cost here. The S21-200TH is rated at 3010W, let's say 3kW for easy sums. 3 x 24 x 30days = 2,160kWh per miner/month. Feeding that number into the PEA bill-estimator here https://eservice.pea.co.th/estimatebill/# gives an overall cost of 15,300Baht per miner/month. Is it still viable at that level? How about mining other coins? By the way. Powering one miner with solar would need 70 x 340W (about 140m2) panels plus associated inverters and battery packs.

Running here: -

Too risky.

You size the breaker to protect the cable (2.5mm2) and to handle the potential start-up surge from a conventional A/C. Modern inverter units don't have the surge but it never hurts to be future-proof in case your unit isn't big enough. We wired all our A/C locations in 4mm2 (on 20A breakers) "just in case" the additional cost was small.

I thought you may have done that in order to get the extra supply

OK that's the right sort of box for 3-phase. Personally, I wouldn't lose the existing single-phase supply, if it has a 15/45 meter that's an additional 45A! Unless you are going to add a lot to the domestic side of things, I'd just replace the Eaton box with something like the baby Schneider and have done with it. it may also be advantageous to have your mining rig separately metered from the house. Do you have a link to the spec. for your server rack, it's unclear what power supply it needs from the photos. Again, do you have a sparks you can use (the PEA chaps could be available for some moonlighting).

OK, so you have two supplies and two meters. I'd leave the existing alone. Your 50A 3-phase incomer is good for about 8-10 miners spread across the 3-phases, so until you reach that level, I'd keep it as it is. Do you have a pet sparky who can do your wiring? There's a lot of energy and potential death in a 3-phase supply!

The main regulations book you need is "รหัสมาตรฐาน EE 2001-56 มาตรฐานการติดตั้งทางไฟฟ้าสำหรับประเทศไทย พ.ศ. 2556" (Standard EE 2001-56 Electrical Installation Standard for Thailand, 2013). There are associated standards for lightning protection and the like which you probably won't need. Get it here or good bookstores for 225 Baht https://eitstandard.com/มาตรฐานการติดตั้งทางไฟ-2/# As far as I'm aware it is not available in English. Unfortunately, there's not a Thai equivalent of BS7671 or AS3000 which would make life easy. The best we can do is the information published by PEA which is linked in one of the pinned threads. If you want to wire to an English language standard you could do worse than to follow AS3000 (Aussie standard) which would meet or exceed any Thai requirements.

Is it still in use? Where is it getting its incoming supply (your new 3-phase)?

OK, is the Eaton box still in use and being fed from where? Interesting that they gave you a 50A incoming MCCB, are you certain you have a 30/100 supply?

OK THW 2.5mm2 on 20A breakers will do the trick for your outlet circuits, run a green or green yellow 2.5mm2 for ground. Run 1.5mm2 on 10A breakers for lighting. I'd leave the 63A until it "fails" inspection, if the inspector is friendly, it could be "lubricated" into compliance For your pump you need NYY. Run 2 core if you put in a ground rod at the pump.

Could you post a clear photo (close up) of your two existing breakers please. 194V on a nominal 220V supply with minimal load is somewhat worrying! (already 12% low). Can you link to the spec. for your server rack please so we can see its power requirments.

Install a 3-phase incoming breaker and 3-phase board. Post some photos of what you currently have so we can be clear in our understanding. Run your existing board off one breaker + neutral in your new board (if it has a N-E link you will need to removed it as only one link is permitted in an installation). Divide your miners across the 3 phases taking account of the load on one phase presented by your house (how many miners and what type?). Pretty well any of the Schneider 3-phase boards will do the trick with a 100A 3-pole MCCB on the front. You will need a competent sparky to achieve this safely. Have you thought about the cooling load required by your miners? How do miners react to power interruptions? I'm not convinced that mining here is actually viable unless you have a lot of spare solar energy.

Thread is no longer relevant!

How much is your "little bit"? In a TNC-S (MEN) system such as we have in Thailand it's quite possible for there to be a small portion of the overall neutral current flowing through individual ground rods. Unless the voltage in question is significant there is no issue. It is possible that you are seeing a symptom of a poor joint in the neutral somewhere upstream from your location, but in order to know we need to know the magnitude of your "little bit" and what you are using as the reference point.

Beaten to it by 10 minutes! So.

https://www.dailymail.co.uk/femail/article-13257173/jonathan-ross-showers-experts-reveal-bad.html

I'm a Brit, once a week whether I need it or not

Could you post a screenshot of what you are looking at please?

Muang Thong Thani Spur Line site has been shut down for a week for "investigation".