Hioki 3169-20 Instruction Manual page 14

6
Measurement categories (Overvoltage categories)
This product conforms to the safety requirements for CAT III mea-
surement products.
To ensure safe operation of measurement products, IEC 61010
establishes safety standards for various electrical environments,
categorized as CAT I to CAT IV, and called measurement catego-
ries. These are defined as follows.
CAT I
CAT II
CAT III Primary electrical circuits of heavy equipment (fixed installa-
CAT IV The circuit from the service drop to the service entrance, and to
Higher-numbered categories correspond to electrical environments
with greater momentary energy, so a measurement product
designed for CAT III environments can endure greater momentary
energy than one designed for CAT II. Using a measurement prod-
uct in an environment designated with a higher-numbered category
than that for which the product is rated could result in a severe
accident, and must be carefully avoided.
Never use a CAT I measuring product in CAT II, III, or IV environ-
ments.
The measurement categories comply with the Overvoltage Cate-
gories of the IEC60664 Standards.
Secondary electrical circuits connected to an AC electrical out-
let through a transformer or similar device.
Primary electrical circuits in equipment connected to an AC
electrical outlet by a power cord (portable tools, household ap-
pliances, etc.)
tions) connected directly to the distribution panel, and feeders
from the distribution panel to outlets.
the power meter and primary overcurrent protection device (dis-
tribution panel).