DM-45
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 exam-
ples 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.
Statement of Conformity
Greenlee Tools, Inc. is certified in accordance with ISO 9001 (2000) for our Quality Management
Systems.
The instrument enclosed has been checked and/or calibrated using equipment that is traceable to the
National Institute for Standards and Technology (NIST).
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