Iec Measurement Category & Pollution Degree Definitions - Cal Test Electronics CT4447 Series User Manual

CT4447 Series High-Voltage Differential Probes User Manual
IEC Measurement Category & Pollution Degree Definitions
Measurement Category (CAT) - classification of testing and measuring circuits according to the types of
mains circuits to which they are intended to be connected.
Measurement Category other than II, III, or IV: circuits that are not directly connected
to the mains supply.
Measurement Category II (CAT II): test and measuring circuits connected directly
to ultilzation points (socket outlets and similar prints) of the low-voltage mains
installation..
Measurement Category III (CAT III): test and measuring circuits connected to the
distribution part of a building's low-voltage mains installation.
Measurement Category IV (CAT IV): test and measuring circuits connected at the
source of the building's low-voltage mains installation.
Mains Isolated: is for measurements performed on circuits not directly connected to a
mains supply.
Pollution - addition of foreign matter, solid, liquid, or gaseous (ionized gases) that may produce a
reduction of dielectric strength or surface resistivity.
Pollution Degree 2 (P2) - only non-conductive pollution occurs except that occasionally
a temporary conductivity caused by condensation is expected.
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