About Server City

Server City is a small, self-running planning site for anyone fitting out a server closet, a network rack or a homelab: lay out the rack, add up power, heat and weight, and estimate UPS runtime.

How the numbers are worked out

• Rack units: 1U is 1.75 inches (44.45 mm) of rack height, the EIA-310 standard. Positions are counted from U1 at the bottom.
• Placement: devices you pin stay where you put them; the rest go heaviest first into the lowest free space, because weight low keeps a rack steadier.
• Amps: watts divided by volts. This treats the load as watts drawn at the wall; nameplate ratings are usually higher than real draw, so a plan built on nameplate figures errs on the safe side.
• 80% line: a breaker should carry no more than 80% of its rating as a load that runs for three hours or more (the US National Electrical Code sizes the breaker at 125% of continuous load, NEC 210.20(A)). Local code and your electrician govern.
• Heat: nearly every watt a computer draws ends up as heat. 1 W = 3.412 BTU per hour; 12,000 BTU per hour is one ton of cooling.
• UPS runtime: battery volts x amp-hours x inverter efficiency x the share of the battery you allow it to use, divided by the load. Real runtime is shorter at high loads, in the cold and as batteries age: the maker's runtime chart for your model is the better guide.
• UPS size: watts divided by the power factor gives volt-amps; the planner adds 25% headroom.

Independent

Server City is built and run by WeldonPC, a computer services company in Ohio. Apart from WeldonPC it is not connected to any equipment maker, rack maker or hosting company, and it sells no hardware or hosting itself. Its public pages carry one banner ad from AdEngine, WeldonPC's own small ad network, which for now shows WeldonPC's own services; the Rack Book carries none (see Privacy). It uses no AI and contacts no equipment: it only does arithmetic on what you type.

Spotted something wrong? Please tell WeldonPC through weldonpc.com/contact.