Keysight U1610/20A User’s Guide 7
Measurement Category
This instrument is intended to be used for measurement in Measurement
Category II and III.
O Other circuits that are not directly connected to the mains.
Measurement CAT II Measurements performed on circuits directly connected
to a low-voltage installation. Examples are measurements on household
appliances, portable tools, and similar equipment.
Measurement CAT III 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 Measurements performed at the source of the
low-voltage installation. Examples are electricity meters and measurements on
primary overcurrent protection devices and ripple control units.