Topic: 800a 208v Service - Need some guidance. (Read 324 times)

Hmmm.

Three phase power math is a little different that shown above here.

800A 3 phase service will definitely supply 100 S9's.

100 S9's = 135kW approx.

135kW/.208kV/SQRT(3) = 375A per phase

375A/80% = 469 Ampacity Required, so 800Amps is plenty.


You can use single phase PDU because all your loads are single phase.

The two pole panel breakers need to be 10A rated for each S9 they power. This is because the load is <7.5A continuous which is <80% of the breaker rating. For example, if you are going to drive 10 S9s on one breaker, it should be rated at 100A. If you use PDUs you should size the breakers and circuits to match the PDUs capacity

I don't do it that way, I just use 20A breakers to feed 20A duplex 220V receptacles. That would be 12-13 two-pole breakers in each of 4 panels. Your electrician can install it all, likely cheaper than the PDUs. Each duplex receptacle will power two S9s. You could pay the electrician to install 50 receptacles then plug in 50A PDUs, but that would cost much more.

You could also get tricky with 3-pole breakers feeding 3-phase PDUs. They rotate the phases internally, like AB, BC, CA then repeat down the PDU. You'd need outlets in multiples of 3 and capacity of 10A each. So a 6 outlet PDU would need to be rated at 60A to keep all the phases balanced. But again, that would costs more.

I allow 1 linear foot for each miner with PSU. So a 4 foot shelf would hold 4 miners and need two receptacles.

I would put in about 4 20A single pole breakers for 120V convenience outlets. You'll need a coffee pot set well away from the miners. Also, firewall, routers, switches, lighting, cellphone and laptop chargers, etc...

Add two, 3-phase breakers in each panel to drive 8 fans. You need a 20% overdrive for cool intake air from the North side of the building and a 50% overdrive to exhaust air out roof vents. Airflow will need to be 25,000 CFM through the miners when it's hot outside. So 30,000 CFM input and 37,500 exhaust. I use an n+1 fan strategy so I would use 4 X 10,000 CFM on the input and the same on the output as I don't need redundancy on the output. Three phase motors are better than single phase motors in every way. If you're really cool it would be good to install VFD drives on each fan motor to save some fan power cost and noise, but not necessary. I like to measure and regulate the pressure in the room with the VFDs.

I isolate the air intake side from the output side with a physical barrier. I seal the hot air side and suck the hot air out with those roof ventilation fans.

I hate duct work so I always put the mining room on the North side of the building. Don't forget to filter the intake air.

I would also suggest asking for a shunt trip type breaker for the 800A. You can then wire the shunt trip to an EPO button and the fire alarm panel. This is required in many locals, especially if it's not maned 24x7. It's be a good idea to meet with the fire inspector prior to building anything. Tell him your running a small computer data center. Give him the nominal power and outside airflow plans. He'll let you know all the requirements and really appreciate that you met with him before building.

 

100 S9s would need 750total amps in 240v with a buffer +-10%. Divide that by 3 so you would need 250 amps per leg in 240v just for the miners. It’s always best to have more then less. I would ask for 1200 amp service or if available 600 amp 480v then step it down in the building. It’s more efficient when running that kind of power.

I have generators that produce that kind of power. 480v scares the crap out of me. Good luck!!!

A good grounding is for the safety, to avoid any touch voltages.

https://en.wikipedia.org/wiki/Earth_potential_rise#Step,_touch,_and_mesh_voltages

I think you are going to need more power if you want to run 100's of S9's.

If I have the numbers correct a 200 amp 3 phase can deliver a little under 72,000 amps.  (Single phase can provide 48,000)

You should not run it over 80%, so 72,000 * .8 =  57,600 usable

An S9 figure 1400w (I would use 1500w to be safe)

57,600 / 1400 = 41 units

41 units * 4 = 160 S9 maximum

Still have to have lights and air handling equipment. Each S9 moves approx 250cfm of air.

160 x 250 = 40,000 cfm of air if it is hot.

I ran a GPU farm with 800 amps and it is a lot of heat to dissipate.

The above is not meant to be negative but to point out what the numbers say. Someone correct me if I misspoke on any of the numbers.

Good luck!

Do I need to tell the city/county what I will be doing? Will there be inspections by the city/county? Do I need fire protection?

I assume people that have these set up on larger scales either live there or have someone on staff 24/7? Will i need someone there 24/7 to monitor if i am running several hundred s9, l3+ etc?

Thanks for the advice!

less than 6 cents per kw/h

Not sure how much for the hook up. The lease is around $.60/sqft per month.

What else am i missing in terms of telling the owner how to set it up?

I don't really understand why you need that many grounding. You will only use the phases on 208V and pretty much 0 (fans, etc.) on the 120V. You do need the ground, but very little power will be there. I think you should worry more on the phase wires, not the neutral.
I assume commercial the zoning will make your life easier (noisy) and maybe they planned for delivering more power too when they built out the delivery lines.

Do you know how much will you pay per KWh?
How much for the hookup?

Does anyone use PDUs from Raptor Power Systems? I want to order custom metered and monitored PDUs from them. Does this make sense for a large scale operation?

From my electrician

"Just request from him (the owner/builder) all breakers 50a 2 pole 208v in those panels. And 4-5 breakers 1 pole 120v 30a. Place panels as close as possible to the miners. tell him to do a very good grounding system for you, very important. 4 ground rods, 15 feet apart, all connected with 3/0 bare copper, and then to main service gnd, and jumper to neutral. you will need low resistance ground"

The owner is building it for my needs. I will either chip in towards the build for a reduced lease rate or pay higher rate on my lease. The owner is going to talk to the electricity company the constant draw should be okay with them. It is "Commercial Gateway" zoned, if this means anything to me?

Its in midwest. not a hot area by any means.

I'm looking to build something similar to this: https://www.youtube.com/watch?v=GE6N5ktUBKw

Please need some more answers and guidance. Thanks.

You can use APC AP7516. Plan looks good, just be sure to use thick enough cables...
Nothing special IMHO, just use oversized everything and make them understand how much constant load you will put on.

Can you share a few things?
Which part of the states are you doing this?
How much is your electricity rate?
Do you have the order with the power company and they accepted it already?

Hello, I want to move my Antminers into a warehouse that is being built as we speak. The building owner will install the electrical as needed but I am not too sure what I should exactly be asking him to set up.

I have asked him to provide 800a 208v three phase service with 4 200a subpanels. The transformer will be 800a also. I am not sure if its wye, delta etc. Whats do I need exactly? Is there anything I am missing?

The panels should be places in close proximity to eachother, on the same wall?

In term of PDUs (tripp lite etc) i will need three phase or single phase PDUs?

Thanks for the help. I will send a $50 litecoin tip to whoever answers my post thoroughly.