Topic: Worth it to upgrade to 220V AC service? (Read 458 times)

One of the first steps in a power supply is the AC-DC conversion process where you will immediately loose .8-1v.  The difference between 10A at 120 vs 5A at 220v would be ~5w.  For that example, that is nearly 44 kwh of saved power and less heating/stress in the power supply.

Does it matter?  I guess it depends on the size of the mine and the cost of your electricity.  You can also loose a significant amount of electricity in extension cords AND older outlets.  If you grab onto an outlet and it is warm, you are paying for that heat.

When I opened up my HP PDU I saw a 50A breaker for main rocker switch and 4 x 15A for each switched plug on the PDU.
Why is PDU rated for 30A? It seems like a 50A breaker inside PDU would not protect a 10 gauge wire with 30A breaker at the panel?
What am I missing?

My PDU is this one but I assume all 30A PDU have 50A breaker inside or am I wrong?
https://www.amazon.com/HP-EO4501-MODULAR-CONTROL-UNIT/dp/B014S24VAU

Exactly. My 8 cent power in more like 10-11 cents/kWh once I add up customer fee, fuel delivery, taxes, etc.
Divide the total $ amount of your electric bill with the total kWh usage and that's your true cost.

For example, $400 monthly electric bill with 2500kwh total monthly usage: 400/2500=$0.16. So your true cost is 16 cents/kWh, not the 12 or whatever cents listed on your bill.

If you want to scale, building out is a fact of life. I'd rather build out something I can reboot without leaving my desk. But that's just me.

I just setup 2 of these 30A circuits in my house. The Bitmain A3s I have on the way will pay off my additional cost in about 12 hours, and themselves in a couple days.

Is your $0.12/kWh just your supply cost or does it also include the cost to deliver/distribute that electricity to your house? Because your actual cost maybe higher.

If he's running S9s at 1350w, he can only run 4 of them on the 30A circuit. Plus all this additional expense is going to impact his ROI and profitability for his home mining operation. I hope you didn't pay 6k on eBay for the miner as it's going to take you over a year to break even at "current difficulty" and price of BTC. At the currently insane price of miners, I don't see how anyone in the U.S. can make a profit if they buy them now. The calculators can't predict future difficulty either so what may look like a good investment now, may look like a bad investment 2 months from now.

Residential electric in the USA is supplied by a split phase 120v system. It's a 4 wire system with 2 hots, 1 neutral, and 1 ground. The ground and the neutral are NOT the same thing. The neutral carries live current and will kill you if you touch it. The ground is generally safe unless your house happens to get hit by lightning when you touch it.

When electric is supplied to your outlets they run 3 wires, 1 hot, a neutral, and a ground. This provides 120v -> neutral, and grounding for safety. Because the system is split phase, when one hot is +120v the other hot is -120v. The difference between the 2 is 240v. If you use a 2 pole breaker in your breaker box and run 2 hots and a ground, you would get 240V service.

The costs for a 240V setup are pretty minimal.

A 30A 2 pole breaker will run you about $20
The cost of 10awg/3 wiring (without conduit, which type of conduit you need will depend on code) is about $1/foot.
Steel flex conduit at 1/2" (probably only big enough for 1 wire) is about $0.3/foot
From there, you can either buy an off the shelf PDU with a twist lock type connector or have an electrician manually wire up some 240v plugs. Electrical code would require him to use a different physical plug at 240v. He'd have to use a NEMA 6-15R, 6-20R, or 6-30R.. This means you'd need to order special power cables for your miners, but it's not that big of a deal to get them at $5 a pop. I'd recommend just installing a single twist lock and getting an enterprise grade PDU for $600, it'll save you on electrician costs.. And if you ever need to replace the PDU, you can do that yourself. Tripplite makes some 240V single phase PDUs. Eaton also makes some. A switched PDU starting at around $800/ea would give you remote reboot capability through a web interface. A basic PDU starting at around $200/ea would just provide the electrical distribution and maybe some power usage information (amp, volt, etc). Using the PDU, you'd also need special power cables.
The twist lock connector will cost you about $20.

For a single 240V 30A run at 300 feet which would give you a total of 7.2kW (5.76kW usable) you're looking at about $430 material cost, another $200-$800 for PDU, and whatever your electrician wants. You might want to check, in some places, home owners are allowed to do some electrical work themselves. I know a guy who did all of the electrical work for his home, which he also built himself. He was not a master electrician.

This will let you put up to around 5 ASIC miners in your mining area. I'd recommend running a separate line specifically for the cooling fans and put them on a different circuit. You could use a smaller breaker (or maybe the existing 120v line) for that.

Your house probably has a 200A or 400A main. If you wanted, you could have your electrician run multiple lines, install multiple twist locks, and for it to be possible to grow in the future without needing additional electrical work. It really just depends how many slots you have free in your breaker box. If you're planning to go heavily into mining, i'd say, run at least 2x 30A 240v lines (11.52kW usable) and use the 120v 10A line for lighting and fans... Maybe upgrade it to a 20A breaker (assuming the wire's ampacity allows for it)...

Beyond being able to run more power over the same sized lines, you'll also get around a 5% (max) efficiency increase in the PSU over 120v (your miners will use less power). The savings at 11.52kW with 0.12/KWH power costs would be around $25-35/month. There's an example efficiency curve for computer PSUs under load at 120v, 208v and 240v at this url: http://www.apc.com/salestools/SADE-5TNQZ7/SADE-5TNQZ7_R3_EN.pdf


Basic PDU with Nema L6-30P (the plug is P receptacle is R (L6-30R)):
https://www.newegg.com/Product/Product.aspx?Item=N82E16812120339&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-Power%20Distribution%20Units-_-Tripp%20Lite-_-12120339&cm_sp=&AID=10440897&PID=1796839&SID=277680130

Switched PDU (remote reboot, remote monitoring, etc) with Nema L6-30P:
http://www.pcm.com/p/TrippLite-PDU-(Power-Distribution-Unit)/product~dpno~40780377~pdp.bceibfga

...


Cooling is another story entirely...

1kW is 3412BTU/hr
11.52kW is 39306.24BTU/hr

A 3-4Ton airconditioner cools about 40,000BTU/hr, plus you need to factor in the sun hitting it, lack of insulation, etc. Then you're going to need to worry about condensation, humidity levels, and it's not insulated... Probably looking at atleast $3,000 here..

Air cooling is doable, but it depends how hot it gets on your hottest month. You'd need to do calculations there to determine heat transfer efficiency between ambient temp, and your miner temp... Then you'll need to figure out how much air you need to move to completely remove all the air in your mining area in a time frame based upon the volume of the building. A large fan installed could run you about $100-$200. You could DIY a radiator or do evaporative using tap water during the hottest months / days. Your water bill would go up but it would drop the input air temperature by 10-20 degrees or more.

Here's a DIY evaporative cooler:
https://www.youtube.com/watch?v=J_ubf0zqvSQ

Same principle, you just need to do the same thing on a 30,000 CFM belt fan.

Another option is to use water cooling and then build a large custom radiator external to the building -- you can find used water chillers on ebay.. But who knows how long they're going to last you before the motor or pump dies..

https://www.ebay.com/itm/Schreiber-Air-Cooled-Water-Chiller-4-Ton-7853/322908028460?hash=item4b2ed17e2c:g:8ewAAOSw7z1aHJNw

I would probably go aircooling and build my own radiator.

Yes I am in the USA.

Are you in the USA? If yes, I'll type out all the stuff you need to know. If no, I'll save my fingers the pain.

I read on some DIY forums about people who upgraded just the circuit and not the wiring. The higher amperage burned through the old wires and caused fires. Thanks for hashing this out with me!

The benefit is you can have more power delivered.

Wire is rated in amps (if you look in your breaker panel, you should have like 15A breakers, maybe some 20A, and some 30A).

This isn't to protect the devices, this is to protect the wire from melting/starting on fire.

Has nothing to do with voltage - amerage is what kills stuff (and people).


So, you can have 200A of 110 delivered from the electric company (common for most US houses built in the last few decades), or you could call them and have 200A of 220v delivered.

You're going to pay the same rate, but you'll have twice as much available capacity on the 220v circuit.



And yes, I have professionals do it too.  I just read a lot on the internet to learn about stuff so that A) I can talk to them intelligently, and B) I know enough that they aren't fucking it up or ripping me off.

Oh, interesting. It’s pretty clear I don’t know much about electricity (thus having a professional to it). I always thought V=IR so 110V=(10A)(11Ω) but if you’re at 220V=(5A)(44Ω) and since Wattage=V*I then with a 220V*5A=1100W but 110V*10A=1100W.....well yeah it is the same.

So is there any advantage of going 220 vs 110? Better integrity of the power? Anything you can think of?
 

False.

Your electrical cost will not go down.

The equipment still uses the same amount of power (rated in watts).  You are billed by kwh (# of watts / 1000 * cost per kwh = cost per hour to run equipment).

If you deliver 1100 watts on 110v power, that's 10A.

If you deliver 1100 watts on 220v power, that's 5A.

Still the same 1100 watts.

Gentlemen,
My mining farm is located in a small building behind my house. The 110V AC 10A circuit it is on will soon be overloaded and I’ll pay a licensed electrician to come and add a new line. Would it be worth it to have the electrician run a 220V line instead of 110V? My understand is 220V service used half the amperage as 110V and therefore my electrical cost should be lower. I’m at $0.12/kWh at the moment. As the building is uninsulated I currently don’t have to spend money on cooling but in a few months I will have to actively cool and exhaust the building and, therefore, a ductless minisplit running off 220V might be the best way to go.

Thoughts? Ideas?