Measurement Category 
 
Measurement Category 
MSO2000A/DS2000A series digital oscilloscopes can make measurements in Measurement 
Category I. 
 
 
WARNING 
This oscilloscope can only be used for measurements within its specified measurement 
categories. 
 
Measurement Category Definitions 
Measurement category 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. In the latter case, transient stresses are variable; for that reason, 
the transient withstand capability of the equipment is made known to the user. 
 
Measurement category II is for measurements performed on circuits directly connected to the low 
voltage installation. Examples are measurements on household appliances, portable tools and 
similar equipment. 
 
Measurement category III is for 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, for example. Stationary motors with permanent connection to the fixed 
installation. 
 
Measurement category IV is for 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.