During Use; After Use; Definition Of Measurement (Overvoltage) Category - HT 64 Bedienungsanleitung

1.2.

DURING USE

Please carefully read the following recommendations and instructions:
Failure to comply with the caution notes and/or instructions may damage
the instrument and/or its components or be a source of danger for the
operator.
 Before activating the rotary switch, disconnect the test leads from the circuit being
measured.
 When the instrument is connected to the circuit being measured, do not touch any
unused terminal.
 Do not measure resistance in case external voltages are present; even if the
instrument is protected, an excessive voltage may cause malfunction.
 While measuring, if the value or the sign of the quantity being measured remain
unchanged, check if the HOLD function is enabled.
1.3.

AFTER USE

 When measurement is complete, set the rotary switch to OFF to switch off the
instrument.
 If the instrument is not to be used for a long time, remove the batteries.
1.4.

DEFINITION OF MEASUREMENT (OVERVOLTAGE) CATEGORY

Standard IEC/EN61010-1: Safety requirements for electrical equipment for measurement,
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control and laboratory use, Part 1: General requirements
category, commonly called overvoltage category, is. § 6.7.4: Measured circuits, reads:
(OMISSIS)
Circuits are divided into the following measurement categories:
 Measurement category IV is for measurements performed at the source of the low-
voltage installation.
Examples are electricity meters and measurements on primary overcurrent protection
devices and ripple control units.
 Measurement category III is for measurements performed on installations inside
buildings.
Examples are measurements on distribution boards, circuit breakers, wiring, including
cables, bus-bars, junction boxes, switches, socket-outlets in the fixed installation, and
equipment for industrial use and some other equipment, for example, stationary motors
with permanent connection to fixed installation.
 Measurement category II is for measurements performed on circuits directly
connected to the low-voltage installation.
Examples are measurements on household appliances, portable tools and similar
equipment.
 Measurement category I is for measurements performed on circuits not directly
connected to MAINS.
Examples are measurements on circuits not derived from MAINS, and specially
protected (internal) MAINS-derived circuits. In the latter case, transient stresses are
variable; for that reason, the standard requires that the transient withstand capability of
the equipment is made known to the user.
CAUTION
, defines what measurement
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EN - 3
HT64