Greenlee CM-700 Manuel D'instructions page 15

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CM-700 • CM-750
Overvoltage Installation Categories
These definitions were derived from the international safety standard for insulation
coordination as it applies to measurement, control, and laboratory equipment. These
overvoltage categories are explained in more detail by the International Electrotechnical
Commission; refer to either of their publications: IEC 1010-1 or IEC 60664.
Overvoltage Category I
Signal level. Electronic and telecommunication equipment, or parts thereof. Some examples
include transient-protected electronic circuits inside photocopiers and modems.
Overvoltage Category II
Local level. Appliances, portable equipment, and the circuits they are plugged into. Some
examples include light fixtures, televisions, and long branch circuits.
Overvoltage 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.
Overvoltage 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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