Typically, co-location providers build out the rack electrical on-demand to customer specifications. Due to the variances in provisioning and client requirements, it doesn't make sense to waste the effort of pre-provisioning power until the rack space is sold.
New racks... no power feeds (I had to wait 12 hours for Union electricians)
You seem to have another question about sizing power. What do you mean by 1000W per 4U? You should list the hardware you intend to use in a more understandable form.
- How many servers do you have?
- What make/model of server are they?
In terms of power density, data centers are rated for a certain amount of cooling and power per square-area. So unless you're in a high-desity facility, it's likely that you wouldn't be able to fill a rack with servers. You'll run out of power and cooling allotment well before you can fully populate the rack.
Power is traditionally delivered on one or two feeds per rack, and is rated at a certain Amperage. Electrical code typically limits you to the use of 80% of the circuit's limit. The power feeds can be A/B redundant, to which you'd only be able to use 40% of the capacity of each circuit...
But again, you may not even want redundant power or be using equipment with dual power supplies. So this goes back to what you wish to install at the colo. If your servers collectively consume less than 1000W, you can get by with 1 or 2 20A or 30A circuits. Looking at the Netelligent configuration tool, they seem flexible and willing to provide whatever you need.
My colo power utilization graph. I hover at 75% of the circuit's capacity.
You have a very unique use case in that you'll be using specialized ASIC Bitcoin-mining hardware that has a known power consumption rate.
In this case, I would opt for larger circuits. You'll want 30A circuits, and can possibly run up to three units per circuit. Likely only two per. Real measurements show these running at 8.7A per unit on 110-120V circuits. 208V is an option at the colo, but you'd need to ask the datacenter about their efficiency and how they're providing their 208V.
With four FAT circuits, you could potentially accommodate 10 units, but you'll likely have to buy multiple racks to handle cooling and thermal concerns. I mentioned that colo facilities are rated for a certain density; often 4,000-6,000W/rack.
At this point, tell the potential colo provider exactly what you have and intend to do, and they'll make it happen and give you an accurate outline of cost/space/cooling/power variables.