OWON B35(T) - Manual (Page 8)

1.Safety Information
3
Measurement Category
The multimeter has a safety rating of 1000 V, CAT III.
Measurement category definition
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.