Extech EX623 Operating Manual

User's Guide

400Amp True RMS AC/DC Clamp
Meter with IR Thermometer

Model EX623

Patented

Introduction

Congratulations on your purchase of this Extech EX623 True RMS Clamp Meter. This meter
measures AC Current, DC Current, AC/DC Voltage, Resistance, Capacitance, Frequency,
Diode Test, Duty Cycle and Continuity. Special features include Dual Input Thermocouple
Temperature, Non-Contact IR Temperature and Non-Contact Voltage detector. The double
molded case is designed for heavy duty use. This meter is shipped fully tested and calibrated
and, with proper use, will provide years of reliable service.

Safety

International Safety Symbols

This symbol, adjacent to another symbol or terminal, indicates the user
must refer to the manual for further information.

This symbol, adjacent to a terminal, indicates that, under normal use,
hazardous voltages may be present

Double insulation

WARNING

CAUTION

PER IEC1010 OVERVOLTAGE INSTALLATION CATEGORY

OVERVOLTAGE CATEGORY I

Equipment of OVERVOLTAGE CATEGORY I is equipment for connection to circuits in
which measures are taken to limit the transient overvoltages to an appropriate low level.

Note – Examples include protected electronic circuits.

OVERVOLTAGE CATEGORY II

Equipment of OVERVOLTAGE CATEGORY II is energy-consuming equipment to be
supplied from the fixed installation.

Note – Examples include household, office, and laboratory appliances.

OVERVOLTAGE CATEGORY III

Equipment of OVERVOLTAGE CATEGORY III is equipment in fixed installations.
Note – Examples include switches in the fixed installation and some equipment for industrial
use with permanent connection to the fixed installation.

OVERVOLTAGE CATEGORY IV

Equipment of OVERVOLTAGE CATEGORY IV is for use at the origin of the installation.
Note – Examples include electricity meters and primary over-current protection equipment

This WARNING symbol indicates a potentially hazardous situation, which
if not avoided, could result in death or serious injury.

This CAUTION symbol indicates a potentially hazardous situation, which
if not avoided, may result damage to the product.

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SAFETY NOTES

• Do not exceed the maximum allowable input range of any function.

• Do not apply voltage to meter when resistance function is selected.

• Set the function switch OFF when the meter is not in use.

• Remove the battery if meter is to be stored for longer than 60 days.

WARNINGS

• Set function switch to the appropriate position before measuring.

• When measuring volts do not switch to current/resistance modes.

• Do not measure current on a circuit whose voltage exceeds 600V.

• When changing ranges always disconnect the test leads from the circuit under test.

CAUTIONS

• Improper use of this meter can cause damage, shock, injury or death. Read and
understand this user manual before operating the meter.

• Always remove the test leads before replacing the battery or fuses.

• Inspect the condition of the test leads and the meter itself for any damage before

operating the meter. Repair or replace any damage before use.

• Use great care when making measurements if the voltages are greater than 25VAC
rms or 35VDC. These voltages are considered a shock hazard.

• Always discharge capacitors and remove power from the device under test before
performing Diode, Resistance or Continuity tests.

• Voltage checks on electrical outlets can be difficult and misleading because of the
uncertainty of connection to the recessed electrical contacts. Other means should be
used to ensure that the terminals are not "live".

• If the equipment is used in a manner not specified by the manufacturer, the protection
provided by the equipment may be impaired.

Function Maximum Input

A AC, 400A DC/AC
A DC 400A DC/AC
V DC, V AC 600V DC/AC
Resistance, Capacitance, Frequency, Diode Test 250V DC/AC
μA 4000 μA
Type K Temperature 30V DC, 24V AC

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EX623 V2.2 07/08

Description

Meter Description

1. Current clamp

2. Clamp opening trigger

3. IR thermometer and Laser Button

4. HOLD/BACKLIGHT button

5. MODE / ZERO button

6. Backlit LCD Display

7. Type K input jacks

8. Multimeter input jacks

9. IR thermometer sensor and Laser pointer (rear)

10. Function switch

11. PEAK button

12. MAX/MIN button

13. Range button

14. Thermocouple display button

15. Battery compartment (rear)

16. Non-Contact Voltage Detector

17. NCV LED indicator

18. Input shutter

Display icons Description

HOLD Data Hold
APO Auto Power Off
AUTO Autoranging

P Peak Hold

DC Direct Current
AC Alternating Current
MAX Max reading
MIN Min reading
Low battery
ZERO DCA or CAP zero
mV or V Milli-volts or Volts (Voltage)
Ω Ohms (Resistance)
A Amperes (Current)
F Farad (Capacitance)
Hz Hertz (Frequency)
% Duty Ratio

o

F and oC Fahrenheit and Celsius units (Temperature)

T

1, T2, T1-T2 Therocouple 1, Thermocouple 2, Thermocouple difference

n, m, μ, M, k Unit of measure prefixes: nano, milli, micro, mega, and kilo

)

)

•

) Continuity test

Diode test
Laser pointer

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EX623 V2.2 07/08

Operation

NOTES: Read and understand all Warning and Caution statements in this operation
manual prior to using this meter. Set the function select switch to the OFF position when
the meter is not in use.

Input Shutter

The Input Shutter inhibits simultaneous connection to the thermocouple jacks and the
DMM input jacks. This is a safety feature which prevents a potentially hazardous condition
from existing during high voltage measurements. Slide the shutter up for test lead
measurements or slide it down for thermocouple temperature measurements.

Non-Contact Voltage Detector

WARNING: Risk of Electrocution. Before use, always test the Voltage Detector on a

known live circuit to verify proper operation.

1. Rotate the Function switch to any measurement
position.

2. Place the detector probe tip on the conductor to be
tested.

3. If AC voltage is present, the NCV detector light will
turn on with a steady red light.

NOTE: The conductors in electrical cord sets are often

twisted. For best results, move the probe tip along
a length of the cord to assure placing the tip in
close proximity to the live conductor.

NOTE: The detector is designed with high sensitivity. Static electricity or other sources of

energy may randomly trip the sensor. This is normal operation.

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