During Use; After Use; Overvoltage Categories - Definitions - Tenmars TM-507 User Manual

Insulation tester
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1.2.

DURING USE

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.
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.
CAUTION
CAUTION
EN - 3
TM-507

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