Understanding colo pricing with respect to power needs
take a look at hardware vendor specs. dell for instance has nice online power calculator. it calculates btu / wats / amps for given setup [ you configure type of box, number of cpus, memory size and hdds ]. it even lets you assume low/high load.
even if you dont use dell hardware that calculator can give you a hint how much power disks/cpus/memories consume.
i assume ~1A per server with dual psu, dual quad core [ regular xeon e54xx ~2.5GHz, not low voltage], two hard drives, 4x 2GB ram. ymmv.
edit: ~1A @ 220V.