Jargon Buster

Don’t understand our terminology or a little lost with our acronyms? See the information below and in the following pages:

2N Measure of resilience (see pages 2-4)
A Ampere (Unit of electrical current)
AHU Air Handling Unit
ATS Automatic transfer switch
CER Central equipment room
CRAC Computer Room Air Conditioning
DX Direct expansion
EPO Emergency Power Off
HV High voltage
kVA kilo volt amp (unit of electrical power)
mVA mega volt amp
MTBF Mean time between failure
MTTR Mean time to repair
N+1 Measure of resilience (see pages 2-4)
PDU Power distribution unit
SPOF Single Point of Failure
UPS Uninterruptible power supply

Discrimination

This refers to the relationship between the operating characteristics of cables, fuses and circuit breakers. A system with satisfactory discrimination will clear an electrical fault quickly and as close to the fault as possible; thus avoiding unnecessary impact on other circuits/systems.

Failure scenario testing

Failure scenario testing is a procedure adopted in critical environments that comprises a series of tests undertaken by the Operational Staff for the purposes of familiarisation with likely critical failures and the procedures necessary to maintain continuity of engineering systems operation to support the business requirements.

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