User Manual

Product Description
R&S
®
RT-ZHD07/15/16/60
8User Manual 1800.2588.02 ─ 01
1.2 Measurement Categories
To ensure safe operation of measurement instruments, IEC 61010-2-030 defines par-
ticular safety requirements for testing and measuring circuits. The standard introduces
measurement categories that rate instruments on their ability to resist short transient
overvoltages that occur in addition to the working voltage of the instrument and can
exceed the working voltage many times over.
Measurement categories are distinguished as follows:
●
O - Instruments without rated measurement category
For measurements performed on circuits not directly connected to mains, for exam-
ple, electronics, circuits powered by batteries, and specially protected secondary
circuits. This measurement category is also known as CAT I.
●
CAT II:
For measurements performed on circuits directly connected to the low-voltage
installation by a standard socket outlet, for example, household appliances and
portable tools.
●
CAT III:
For measurements performed in the building installation, such as junction boxes,
circuit breakers, distribution boards, and equipment with permanent connection to
the fixed installation.
●
CAT IV:
For measurements performed at the source of the low-voltage installation, such as
electricity meters and primary overcurrent protection devices.
Figure 1-2: Examples of measurement categories
The higher the category, the higher the expected transient overvoltage. Overvoltages
can overload a circuit and cause electrical and physical damage. Therefore, use the
measurement instrument only in electrical environments for which the instrument is
rated.
The measurement categories correspond to the overvoltage categories of the
IEC60664 standards. Working voltages stated in context with measurement categories
are always specified as effective voltages V (RMS) against earth ground.
Measurement Categories