MULTITEST M72 - M73 - M74 - M75
EN - 3
1.2. DURING
USE
CAUTION
An improper use may damage the instrument and/or its components or injure
the operator.
)
Before selecting any function, first disconnect the test leads from the circuit under test.
)
When the instrument is connected to circuits never touch any unused terminal.
)
Do not measure resistance in presence of external voltages; although the instrument is
protected, an excessive voltage may cause malfunctioning.
CAUTION
If the “low battery” symbol is displayed during use interrupt testing and replace
batteries following the procedure described in paragraph 5.2.
1.3. AFTER
USE
)
Disconnect the test leads from the circuit under test and switch off the instrument.
)
If you expect not to use the instrument for a long period remove batteries.
1.4. OVERVOLTAGE
CATEGORIES - DEFINITIONS
Standard EN61010-1 (Safety requirements for electrical equipment for measurement, control
and laboratory use, Part 1: General requirements) defines what a measurement category
(usually called “overvoltage category”) is. At paragraph 6.7.4: Measuring circuits it says:
(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 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.
•
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 norm requires that the transient withstand capability of
the equipment is made known to the user.
