HT HT21 User Manual

HT21
EN - 3
1.2. DURING USE
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 measuring circuits never touch any unused
terminal
 When measuring resistors do not add any voltage. Although there is a protection
circuit, excessive voltage could cause malfunctioning
 If during measurement the displayed values remain constant check whether the HOLD
function is active
1.3. AFTER USE
 After using the instrument turn it off
 If you expect not to use the instrument for a long period remove the battery to avoid
leakages of battery liquids which may damage its inner components
1.4. MEASURING (OVERVOLTAGE) CATEGORIES DEFINITIONS
EN 61010-1: 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. § 6.7.4: Measuring circuits:
(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

HT HT21 Specifications

General

Brand	HT
Model	HT21
Category	Multimeter
Language	English