Overvoltage Installation Categories - Greenlee DM-50 Instruction Manual

DM-50 • DM-55

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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