During Use; After Use; Measuring (Overvoltage) Categories Definitions - Würth DIGITAL-MULTIMETER-TD6 Bedienungsanleitung

Read the recommendations which follow and the instructions in this manual:
CAUTION
An improper use may damage the instrument and/or its components or injure
the operator.
• When changing the range, first disconnect
the test leads from the circuit under test in
order to avoid any accident
• When the instrument is connected to measur-
ing circuits never touch any unused terminal
• When measuring resistors do not add any
voltage. Although there is a protection cir-
• After using the instrument turn it off
• If you expect not to use the instrument for
a long period remove the battery to avoid

1.4. Measuring (overvoltage) categories definitions

The IEC/EN61010-1: Safety requirements for electrical equipment for measurement, control and
laboratory use, Part 1: General requirements, gives a definition of measuring category, usually called
overvoltage category. chapter 6.7.4: Measuring circuits:
Circuits are divided into the following measurement categories:
• Measurement category IV is for
measurements performed at the source of
the lowvoltage installation
Examples are electricity meters and meas-
urements on primary overcurrent protection
devices and ripple control units
• Measurement category III for
measurements performed in the building
installation.
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

1.2. During use

cuit, excessive voltage could cause malfunc-
tioning
• If during measurement the displayed values
remain constant check whether the HOLD
• function is active

1.3. After use

leakages of battery liquids which may dam-
age its inner components
• 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 meas-
urements 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 norm requires
that the transient withstand capability of the
equipment is made known to the user
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