Cost for a 4000 Amp service in a warehouse

[jaykavathe]

I am setting a hosting space (crypto mining rigs) for a client. I am expecting to have about 700 miners (mining computers) with about 1.2 kW power draw on each.
The energy company will provide ample power (480V, 3 phase and as much power needed) by installing transformer right outside the building on their own so I will be just responsible for concrete padding.

Now to bring the power inside, I am wondering what is the cheapest way. I am leasing this warehouse for 3 years so dont want to invest crazy amount into installation (One local company quoted me freaking $300,000 for installation).

All I need is that 4000A service inside the building into a mainboard or say, 20x 200A panels and from there I can run those to 650 machines on the racks using PDUs on
each rack. What would be a cost effective setup and how much that would be? Are there any contractors/electricians here who would work in Columbus, Indiana.

Thank you guys in advance.

 

[augie47]

Related question: How did you come up with the 4000 amp service and why 480v ? Air Conditioning ??
(For the computers I would think you would want 208/120 and no where near4 4000 amps @ 480... If you are feeding HVAC also that MIGHT make more sense)

 

[jaykavathe]

700 rigs x 1200 W/rig divided by 208VAC ~ 4000 Amps.
The rigs would need to be fed with 208-240 V. 480VAC is what will be provided by energy company that I will need to get stepped down.

These are not just computers but mining rigs. Every single rig will pull actual 1200W 24x7 (not just rated at). So those 700 rigs would easily eat up close to 4000 Amps.
Also no HVAC. No HVAC can handle this much heat. Cooling will be with forced air ventilation and I have calculated necessary amount of flow needed. I already have a smaller setup with 40 rigs running for last 5 months without any HVAC and maintaining temps in Indiana summer with 94F Amb temps.

My biggest concern is getting the MDP and cost for it (Just having a MDP from where I could feed the racks myself)

 

[augie47]

Just for reference, a 480v service is almost surely 3 phase and your 1.2 kw computer load on 480 3 phase is closer to 1000 amps load on a 480v 3 phase service unless I made a math error.

 

[jaykavathe]

I am more likely to be wrong in calculation here because I still dont understand 3 phase calculations.
Can you help me here?

So I need, 840kW of power for all my rigs inside. Add another 50kW for peripherals etc. So lets say 900 kW is the requirement inside.
Outside, service is 480V 3 Phase (it is confirmed 3 phase).

What should be the Amperage on my switchboard? I got a quote where the firm is using Eaton Pow-R-Line C switchboard.

 

[augie47]

480v 3 phase 900,000/480 X 1.732 = 1,082 amps. From what you say a major portion of that is a continuous load so you might be looking at a 1300 amp + service. Next standard size I think is 1600.

 

[electrofelon]

As augie said, you are doing your calcs wrong. The miners will be about 1100 amps three phase 480. What is the cooling load? I would suggest getting a competent electrician to assist with the design and calcs.

 

[augie47]

Some of the WA forum guys will likely have input but for that size job you may well need engineered drawings, but for conversations sake a 1200-1600 amp service is closer to your need than a 4000 amp.

 

[jaggedben]

I get that for 900kw continuous load your 208V side requirement comes to 3126A which means your 480V side requirement is 1355A.

For simple 3phase calculations take watts/voltage/1.73.

 

[electrofelon]

Panelboards top out at 1200 amps. You could investigate using two, possibly with 3 main disconnects each, depending on how you need to split and distribute it. Perhaps a switch board is better in this case, too little info to tell.

 

[Ingenieur]

I am more likely to be wrong in calculation here because I still dont understand 3 phase calculations.
Can you help me here?

So I need, 840kW of power for all my rigs inside. Add another 50kW for peripherals etc. So lets say 900 kW is the requirement inside.
Outside, service is 480V 3 Phase (it is confirmed 3 phase).

What should be the Amperage on my switchboard? I got a quote where the firm is using Eaton Pow-R-Line C switchboard.

you need to hire an electrical engineer or contractor

900 kW ~ >1000 kva ~ 1200 A at 480/3 for the servers

you may need 1/2 as much again to cool 1 MW, 300 tons or so

 

[jaykavathe]

Of course, I am not doing it myself, especially installing the switchboard. Once all installation is complete, I will run the cables from sub panels (or breakers) to PDUs on the racks.

But please bare with me, I am not able to understand how 1600A will be sufficient.

Rigs will be hooked up to 208V. So if I hook up my rig to 3 phase, 208V... would that mean my Ampere need will drop as well?
Basically I was calculating 1200W/208 ~ 5.75 Amp per rig but looks like, each rig will pull 1200/(1.732 * 208) = 3.33 Amps.

And if that's correct, it would still amount to 750 * 3.33 = 2331 Amps coming out of my switchboard, right?
I understand that coming in from transformer at 480V/3 Phase, there might be just <1600A coming into switchboard but switchboard will end up distributing ~2400A is what I thought (was thinking more missing on 208/3 Phase calc).

Would anyone care with a quick phone call ....please

 

[augie47]

KW is KW so you basic load is 1200 watts time 700 units or 840 kw.
840 kw at 480v 3 phase is 840,000/480 X 1.732 = 1010 amps (excluding your other load)
840 kw at 208/120 3 phase would be 840,000/208 X 1.732 = 2333 amps.

You obviously will need transformers to covert the 480 to your device voltage

( Using your 900kw number the loads would be 900,000 /480 X 1.732 or 1082 at 208 900,000/208 X 1.732 =2498 amps)

 

[electrofelon]

It sure would be nice if those miners could run on 277v.

 

[jaykavathe]

KW is KW so you basic load is 1200 watts time 700 units or 840 kw.
840 kw at 480v 3 phase is 840,000/480 X 1.732 = 1010 amps (excluding your other load)
840 kw at 208/120 3 phase would be 840,000/208 X 1.732 = 2333 amps.

You obviously will need transformers to covert the 480 to your device voltage

( Using your 900kw number the loads would be 900,000 /480 X 1.732 or 1082 at 208 900,000/208 X 1.732 =2498 amps)

Ok, so that makes sense. My rigs will pull ~2500 Amps being at 208V and Transformer will send 1082 Amps being at 480V.
So seeing that 2500 is the bigger no., I assume my switchboard needs to cover 2500A, right? That's why I went with 4000 A to leave room for expansion.

 

[petersonra]

As augie said, you are doing your calcs wrong. The miners will be about 1100 amps three phase 480. What is the cooling load? I would suggest getting a competent electrician to assist with the design and calcs.

i think more likely an engineer with considerable familiarity with such things. Most of that 1200W is going to be heat that needs to be removed somehow.

 

[drcampbell]

It sure would be nice if those miners could run on 277v.

Maybe they can. Has anybody checked?
If they haven't been purchased yet, has anybody inquired whether they're available in 277 volt?

Most computer power supplies are designed for the international market and operate on 90-250 volts. Many large data centers are supplied with 416Y240 three-phase power. (416 volts line-to-line; 240 volts line-to-neutral) Doing so eliminates one transformation and its associated energy losses. Also, running at a higher voltage, energy loss (and heat generation) in the data center wiring is less.

Do not assume that an input voltage range of 90-250 volts means that they can be run on American 208-volt circuits. 208 volts is achieved by using two hot wires, and many computers cannot tolerate that.

But -- as said above -- you need an electrical engineering firm and/or electrical contractor for a job of this size.

-

... Most of that 1200W is going to be heat that needs to be removed somehow.

All of it.

 

[petersonra]

But -- as said above -- you need an electrical engineering firm and/or electrical contractor for a job of this size.

Probably an HVAC engineer too. Most places are not going to let him install that much air conditioning without plans.

eta: 700 units at 1200W each is almost 3,000,000 BTU/hr or 250 tons of air conditioning. probably take 400+ Amps @ 480V of juice just for the cooling

 

[augie47]

Ok, so that makes sense. My rigs will pull ~2500 Amps being at 208V and Transformer will send 1082 Amps being at 480V.
So seeing that 2500 is the bigger no., I assume my switchboard needs to cover 2500A, right? That's why I went with 4000 A to leave room for expansion.

Nope.. The 480 switchboard needs to cover the 1082 at 480v ..thats 900 kw (1082 X 480 X 1.732)

The same load (900 kw) would be a 2500 amp load at 208 volt..

so on the "minimum" end you would need a 1200 amp 480v service panelboard a 1000 kw transformer and a 2500 amp 208v panelbaord ( In reality you need more due to continuous load and for possible growth and this load:
https://www.bigassfans.com/ )

 

[electrofelon]

i think more likely an engineer with considerable familiarity with such things. Most of that 1200W is going to be heat that needs to be removed somehow.

I don't see why an engineer is necessary for the electrical. I wouldn't hesitate to design that. I would however want the hvac engineered.