User`s guide

66 U2741A User’s Guide
4 Characteristics and Specifications
[1]
Applicable for NPLC >1
[2]
Applicable for NPLC 0.2 and 0.02
Measurement Category The U2741A USB modular digital multimeter is intended to be used for measurement in
Measurement Category II, 300 V.
Measurement Category Definition Measurement CAT I is for measurements performed on circuits not directly connected
to MAINS. Examples are measurements on circuits not derived from MAINS, and
specially protected (internal) mains- derived circuits.
Measurement CAT II are measurements performed on circuits directly connected to
the low voltage installation. Examples are measurements on household appliances,
portable tools, and similar equipment.
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.
User's Guide.book Page 66 Friday, August 8, 2008 9:11 AM