Velleman DVM4 00 Série Notice D'emploi page 6

4. Overvoltage/installation category
DMMs are categorized depending on the risk and severity of transient overvoltage
that might occur at the point of test. Transients are short-lived bursts of energy
induced in a system, e.g. caused by lightning strike on a power line.
The existing categories according EN 61010-1 are:
A CAT I-rated meter is suitable for measurements on protected electronic
CAT I circuits that are not directly connected to mains power, e.g. electronics
circuits, control signals...
A CAT II-rated meter is suitable for measurements in CAT I-environments
and mono-phase appliances that are connected to the mains by means of
CAT II a plug and circuits in a normal domestic environment, provided that the
circuit is at least 10m apart from a CAT III- or 20m apart from a CAT IV-
environment. E.g. household appliances, portable tools...
A CAT III-rated meter is suitable for measurements in CAT I- and CAT II-
environments, as well as for measurements on (fixed) mono- or poly-
CAT III phased appliances which are at least 10m apart from of a CAT IV-
environment, and for measurements in or on distribution level equipment
(low-voltage distribution boards, lighting circuits, electric ovens).
A CAT IV-rated meter is suitable for measuring in CAT I-, CAT II- and CAT
III-environments as well as on the primary supply level.
CAT IV Note that for all measurements on equipment for which the supply cables
run outdoors (either overhead or underground) a CAT IV meter must be
used.
Warning:
This device was designed in accordance with EN 61010-1 installation category CAT
IV 600V / CAT III 1000V. This implies that certain restrictions in use apply that are
related to voltages and voltage peaks which can occur within the environment of
use. Refer to the table above.
This device is suitable for measurements up to 1000V:

Protected electronic circuits that are not directly connected to mains power, e.g.
electronics circuits, control signals, circuits behind isolating transformer...

circuits that are directly connected to mains power, but limited to:
measurements on mono-phase appliances that are connected to the mains by
o
means of a plug
mono-phase appliances and circuits directly connected to the mains in a normal
o
domestic environment, provided that the circuit is at least 10m apart from a
CAT IV-environment. E.g. household appliances, portable tools, light circuits at
more than 10m from a distribution board ...
 measurements in/on low-voltage distribution boards (distribution boards behind
meter box)
 measurements on (fixed) mono- or poly-phased appliances and circuits except in
CAT IV-environments (e.g. mains outlets, electric ovens, lighting circuits, bus
bars, low-voltage distribution boards and circuit breakers).
This device is suitable for measurements up to 600V:
 Measurements on distribution equipment and outdoor installations including meter
boxes and equipment/circuits outside or remote from the domestic environment
e.g. circuits in sheds, garden houses and free-standing garages , or circuits using
underground wiring e.g. garden lighting, pool-pump...
This device is NOT suitable for:
 Voltages above 1000V
 Currents above 10A
This device is only suitable for measurements up to 600V in