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Power is distributed by the "power bars" attached to the back of the racks. These present as IEC C13 and C19 outlets. When you install your machine, the support team will supply IEC C14-C13 power leads on request. These should be suitable for use in almost all cases.

We try to balance the load within and between the power bars where possible. When your machine is installed it will be assigned a power-bar outlet (or outlets, in the case of a machine with dual power supplies) with this in mind. After working on your machine, please reconnect it to the same outlet(s). As machines are added and removed, and loads change, we may need to move things around; we will try to schedule this in advance where possible.

In a few cases, equipment will expect C19 or even 13A power. If yours is one of these, please contact support in advance, so that the technicians have time to source or make up something suitable. Note that in no case should the 13A wall sockets be used to power equipment in the racks or shelves, as this would cause a trip hazard.

If you don't know the terms C13, C14 and C19, see the wikipedia article below.


All power in the Informatics Forum self-managed server rooms IF-B.Z14 and IF-B.01 is supplied by the same 200kVA Uninterruptible Power Supply (UPS) system as supplies the main Forum server server room IF-B.02. The purpose of the UPS is to:

  1. Provide a clean and conditioned power supply, in order to deal with power spikes, surges, lags and brownouts which occur on the direct mains supply from from time to time.
  2. Provide a continued power supply in the event of a mains power cut. This is achieved by a large bank of batteries which is an integral part of the UPS system.

At full load, the expected run time on batteries (or 'autonomy') of the UPS which supplies our server rooms is about 30 minutes.

No special action is required by owners of self-managed machines to take advantage of any of this, but the facility exists for any self-managed machine to monitor the UPS, and to automatically shut itself down in the case that mains power has been lost for an extended period, and the UPS is signalling a 'low battery' condition. For details on how to arrange this, please refer to our Monitoring the server room UPS page.

Three phase power

WARNING: Three phase power is in use in the self-managed server rooms.
A machine must only be connected to the power bars fitted to the rack in which the machine itself is housed.

Each individual power bar or 13A socket provides the usual single-phase nominal 240V between live and neutral. However there is a nominal 440V between phases.

Both power bars on any rack use the same phase; however, power bars on different racks might use different phases. The 13A wall sockets use a different phase to the power bars.

Power bars and 13A sockets are all labelled with their circuit numbers, which includes the phase they are on (either L1, L2 or L3.)

A machine must only be connected to the power bars fitted to the rack in which the machine itself is housed.

More info

Find out more about the self-managed server rooms:

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