After Use; Definition Of Measurement (Overvoltage) Category - HT VEGA74 Guía De Referencia Rápida

VEGA74
14
1.1
BEFORE AND DURING USE
Please carefully read the following recommendations and instructions:
• Always disconnect the measuring leads from the circuit being measured
before changing function.
• When the instrument is connected to the circuit being measured, do not touch
any unused terminal.
• During current measurement, any other current near the clamps may affect
measurement precision.
• When measuring current, always put the conductor as near as possible to the
middle of the clamp jaw, to obtain the most accurate reading.
1.2

AFTER USE

• When measurements are completed, switch off the instrument by pressing
the ON/OFF key.
• If the instrument is not to be used for a long time, please follow the instructions
for storage described in § 7.
CAUTION
Before use the instrument please read the user manual downloadable from
www.ht-instruments.com/download website
1.3

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:
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.
Rel. 2.00 - 09/11/22