Extech Instruments EX623 User Manual

User's Guide

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

Model EX623

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.

 This device is not a toy and must not reach children’s hands. It contains hazardous objects as

well as small parts that the children could swallow. In case a child swallows any of them,
please contact a physician immediately

 Do not leave batteries and packing material lying around unattended; they can be dangerous

for children if they use them as toys

 In case the device is going to be unused for an extended period of time, remove the batteries

to prevent them from draining

 Expired or damaged batteries can cause cauterization on contact with the skin. Always,

therefore, use suitable hand gloves in such cases

 See that the batteries are not short-circuited. Do not throw batteries into the fire.

 Do not directly view or direct the laser pointer at an eye. Low power visible lasers do not

normally present a hazard, but may present some potential for hazard if viewed directly for
extended periods of time

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

A 4000 A

Type K Temperature 30V DC, 24V AC

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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)

 Ohms (Resistance)

A Amperes (Current)

F Farad (Capacitance)

Hz Hertz (Frequency)

% Duty Ratio

o

F and oC Fahrenheit and Celsius units (Temperature)

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

T

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

)

)



) Continuity test

Diode test
Laser pointer

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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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