Emerson 7400 - Manual (Page 6)

Safety Procedure
WARNING
This is a class A UPS product. In a domestic environment, this
product may cause radio interface in which case the user may
be required to take additional measures.
WARNING
HIGH EARTH LEAKAGE CURRENT: EARTH CONNECTIONS IS
ESSENTIAL BEFORE CONNECTING THE INPUT SUPPLY.
This equipment must be earthed in accordance with local
electrical codes.
WARNING
THIS UPS DOES NOT INCORPORATE AUTOMATIC BACKFEED
PROTECTION. A WARNING LABEL MUST BE FITTED TO ALL
EXTERNAL PRIMARY POWER ISOLATIONS STATING.
INSULATE THE UNINTERRUPTIBLE POWER SYSTEM BEFORE
WORKING ON THIS CIRCUIT.