Measurement Categories - Greenlee CMT-80 Instruction Manual

Measurement Categories

These definitions were derived from the international safety standard for
insulation coordination as it applies to measurement, control, and laboratory
equipment. These measurement categories are explained in more detail by the
International Electrotechnical Commission; refer to either of their
publications: IEC 61010-1 or IEC 60664.
Measurement Category I
Signal level. Electronic and telecommunication equipment, or parts thereof.
Some examples include transient-protected electronic circuits inside
photocopiers and modems.
Measurement Category II
Local level. Appliances, portable equipment, and the circuits they are plugged
into. Some examples include light fixtures, televisions, and long branch
circuits.
Measurement Category III
Distribution level. Permanently installed machines and the circuits they are
hard-wired to. Some examples include conveyor systems and the main circuit
breaker panels of a building's electrical system.
Measurement Category IV
Primary supply level. Overhead lines and other cable systems. Some
examples include cables, meters, transformers, and other exterior equipment
owned by the power utility.
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