We have two racks in a datacenter, currently powered by two independent sources. All devices are distributed across four different power extenders, and a few critical ones are first connected to a UPS and then to one of the power extenders.

Our wish is to protect us from: Device 1 connected to a power extender causes short-circuit, this killing the fuse of the branch and all devices on that branch go offline.

Do you have any ideas for best arrangement of both racks to have as good power redundancy as possible? (UPS already made a problem, after an outage it made short circuit to whole branch).

  • You need to have a qualified electrician look at the power system to discover reason for short circuit. Once that is addressed you can look at redundancy options – Dave M Nov 1 '18 at 11:40

In this scenario with a single UPS,

Each rack should have 1 power strip (PDU) fed from UPS ("A side") and 1 fed from "Mains" ("B side) Each host/device should be connected to both strips in that respective rack.

  • Any PDU that has an issue will drop either A-side or B-side in that rack, but not both.
  • If the UPS has an issue, both "A sides" will go down, but B-Side power from Mains will remain
  • If the Mains goes, then both "B sides" will drop, but UPS will keep the A sides up.
  • Plus proper equipment, whihc - in 2018 standard - has dual power supplies. Even lower end switches are available with this. And proper power distribution behind the UPS that will not overload a UPS on a short circuit. – TomTom Nov 1 '18 at 14:53

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