6
Safety Notes
Measurement categories
To ensure safe operation of measuring instruments, IEC 61010 establishes safety
standards for various electrical environments, categorized as CAT II to CAT IV, and
called measurement categories.
DANGER
• Using a measuring instrument in an environment designated with
a higher-numbered category than that for which the instrument
is rated could result in a severe accident, and must be carefully
avoided.
• Using a measuring instrument without categories in an environment
designated with the CAT II to CAT IV category could result in a
severe accident, and must be carefully avoided.
CAT II: When directly measuring the electrical outlet receptacles of the primary
electrical circuits in equipment connected to an AC electrical outlet by a
power cord (portable tools, household appliances, etc.)
CAT III: When measuring the primary electrical circuits of heavy equipment (xed
installations) connected directly to the distribution panel, and feeders from
the distribution panel to outlets
CAT IV: When measuring the circuit from the service drop to the service entrance,
and to the power meter and primary overcurrent protection device
(distribution panel)
T
Outlet
CAT II
Internal
wiring
Distribution panel
Service entrance
Service drop
CAT IV
Power meter
CAT III
Fixed installation
To Next Page
Loading...
