Keysight N2894-60002 User Manual page 17

IEC Measurement Category Definitions and Examples
IEC Measurement Category Definitions and Examples
Definitions and Examples (Clause 6.5.2).
Mains Isolated
Mains isolated is for measurements performed on circuits not directly connected to
a mains supply.
Example. Measurements in circuits not derived from a mains supply and specially
protected (internal) circuits derived from a mains supply. In the latter case, transient
stresses are variable. For that reason, it is required that the transient withstand
capability of the equipment is made known to the user.
Measurement Category II (CAT II)
Measurement category II is for measurements performed on circuits directly con-
nected to the low voltage installation.
Example. Household appliances, portable tools, and similar equipment.
Measurement Category III (CAT III)
Measurement category III is for measurements performed in the building installa-
tion.
Example. Measurements on distribution boards, circuit breakers, wiring including
cables, bus-bars, junction boxes, switches, socket-outlets in the fixed installation
and equipment for industrial use like, for example, stationary motors with perma-
nent connections to the fixed installation.
Measurement Category IV (CAT IV)
Measurement category IV is for measurements performed at the source of the
low-voltage installation.
Example. Electricity meters and measurements on primary over-current protection
devices and ripple control units.
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