Velleman APPA 305 APPA305 ユーザーズマニュアル
製品コード
APPA305
Information sheet
Velleman
®
2/3
Last update: 31/03/2010
2. Overvoltage/installation categories
DVMs are categorized depending on the risk and severity of transient overvoltage that
might occur at the point of test. Transients are short-lived burst of energy induced in
a system, e.g. caused by lightning strike on a power line.
On high-energy circuits this leads to hazardous situations as these circuits might
provide enough current to feed an arc-over resulting in a plasma breakdown or even
a system, e.g. caused by lightning strike on a power line.
On high-energy circuits this leads to hazardous situations as these circuits might
provide enough current to feed an arc-over resulting in a plasma breakdown or even
explosion.
Higher CAT-identification refers to electrical environments with higher power and
Higher CAT-identification refers to electrical environments with higher power and
possibly higher energy transients.
A CAT I-rated meter
is suitable for
is suitable for
measurements on
protected electronic
circuits that are not
protected electronic
circuits that are not
directly connected to
mains power, e.g.
mains power, e.g.
electronics circuits,
control signals…
control signals…
A CAT II-rated meter
is suitable for
is suitable for
measurements in
CAT I-environments
and mono-phase
CAT I-environments
and mono-phase
appliances that are
connected to the
connected to the
mains by means of a
plug and circuits in a
plug and circuits in a
normal domestic
environment,
environment,
provided that the
circuit is at least
10m apart from a
circuit is at least
10m apart from a
CAT III- or 20m
apart from a CAT IV-
apart from a CAT IV-
environment. E.g.
household
household
appliances, portable
tools…
tools…
A CAT III-rated
meter is suitable for
meter is suitable for
measurements in
CAT I- and CAT II-
environments, as
CAT I- and CAT II-
environments, as
well as for
measurements on
measurements on
(fixed) mono- or
poly-phased
poly-phased
appliances which are
at least 10m apart
at least 10m apart
from of a CAT IV-
environment, and for
measurements in or
environment, and for
measurements in or
on distribution level
equipment (fuse
equipment (fuse
boxes, lighting
circuits, electric
circuits, electric
ovens).
A CAT IV-rated
meter is suitable for
meter is suitable for
measuring in CAT I-,
CAT II- and CAT III-
environments as well
CAT II- and CAT III-
environments as well
as on the primary
supply level.
supply level.
Note that for all
measurements on
measurements on
equipment for which
the supply cables
the supply cables
run outdoors (either
overhead or
underground) a CAT
overhead or
underground) a CAT
IV meter must be
used.
used.