1.Safety Information
Measurement CAT I
applies to measurements performed on circuits not directly
connected to the AC mains. Examples are measurements on circuits not derived
from the AC mains and specially protected (internal) mains- derived circuits.
Measurement CAT II
applies to protect against transients from energy-
consuming equipment supplied from the fixed installation, such as TVs, PCs,
portable tools, and other household circuits.
Measurement CAT III
applies to protect against transients in equipment in fixed
equipment installations, such as distribution panels, feeders and short branch
circuits, and lighting systems in large buildings.
Measurement CAT IV
applies to measurements performed at the source of the
low- voltage installation. Examples are electricity meters and measurements on
primary over current protection devices and ripple control units.
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