HT9012
EN - 3
1.2 BEFORE USE
Always keep to the instructions contained in this manual:
CAUTION
Non compliance with the warnings and/or the instructions may damage the
tester and/or its components or injure the operator.
Before changing the switch’s position, take off the clamp jaw from the tested conductor
or the electrical circuit in order to avoid any accident
When the clamp is connected to the circuits to be tested, never touch unused terminals
When testing resistors, do not add voltage. Although there is a protection circuit,
excessive voltage would cause malfunctioning
Before measuring current, remove the voltage-resistance test leads
When measuring current, any strong current near or close to the clamp jaw will affect
the accuracy
When measuring current, always put the tested conductor in the middle of the clamp
jaw in order to obtain a more accurate reading
If the reading value or the sign indication remains unchanged during the measurement,
check if the HOLD function is active
1.3 AFTER USE
Once the measurements are completed, turn the rotary switch to OFF
If you expect not to use the clamp for a long time, remove the battery
1.4 MEASURING (OVERVOLTAGE) CATEGORIES DEFINITIONS
The norm IEC/EN61010-1: Safety requirements for electrical equipment for measurement,
control and laboratory use, Part 1: General requirements, defines what measuring
category, usually called overvoltage category, is. On § 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