User`s guide

Characteristics and Specifications 5
Measurement Category
U1273A/U1273AX User’s Guide 137
Measurement CAT III are measurements performed in the
building installation. Examples are 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, and
some other equipment including stationary motors with
permanent connection to the fixed installation.
Measurement CAT IV are measurements performed at the
source of the low- voltage installation. Examples are
electricity meters and measurements on primary over
current protection devices and ripple control units.