HT instruments SIRIUS87 - Manual (Page 6)

SIRIUS 87
EN - 4
1.2. DURING USE
Carefully read the following recommendations and instructions:
CAUTION
No compliance with the CAUTIONs and/or Instructions may damage the
apparatus and/or its components or injure the operator
.
 Before selecting any function disconnect the test leads from the circuit under test
 When the instrument is connected to the tested circuit never touch any test lead which
is not being used
 Avoid to effect resistance measurements in the presence of external voltages; even
though the instrument is protected a too high voltage may cause malfunctions.
CAUTION
If the symbol is displayed during use interrupt testing and replace
batteries following the procedure described under § 8.2. The instrument is
capable of keeping the data stored even though batteries are not installed.
1.3. AFTER
USE
 When the measurements are completed disconnect the test leads from the circuit
under test and after that switch OFF the instrument
 Remove batteries when the apparatus remains unused for long periods.
1.4. DEFINITION OF MEASUREMENT (OVERVOLTAGE) CATEGORY
Standard “IEC/EN61010-1: Safety requirements for electrical equipment for measurement,
control and laboratory use, Part 1: General requirements” defines what measurement
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.