Recently went through a detailed review of the design of Telehouse Docklands.
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The power system has 3 generators available at all times, only two of which are required to carry the original rated load (which was huge by current standards). There is space for a 4th if required. The building has 3 disjoint cooling loops with redundant pumps. The house power risers are huge floating buss-bars in 2 disjoint risers, each carries 2 independent rails ("A and B").
The only flaw being that (possibly with the exception of the full tenancy contracts) you have to use their switch equipment for power, i.e. you can't get power from 2 different risers to the same 'cage'. Allegedly this is being fixed in v2 being built next door. Saying that, as I said before, to date we haven't had a single power failure. The colo facilities, and the fact there is an IXP (LINX) on site, mean this it's a really useful place to be. Alex Bligh Xara Networks