Extech Instruments EX310 User Manual

User's Guide

Mini Multimeter

with Non-Contact Voltage Detector (NCV)

Model EX310

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Model EX310 - Version 7.1 – 05/2006

2

Introduction

Congratulations on your purchase of the Extech EX310 MultiMeter. The EX310 offers AC/DC
Voltage, AC/DC Current, Resistance, Diode, and Continuity testing plus a built-in non-contact
Voltage Detector. Proper use and care of this meter will provide many years of reliable
service.

Safety

This symbol adjacent to another symbol, terminal or operating device
indicates that the operator must refer to an explanation in the Operating
Instructions to avoid personal injury or damage to the meter.

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.

This symbol advises the user that the terminal(s) so marked must not be
connected to a circuit point at which the voltage with respect to earth
ground exceeds 600V.

This symbol adjacent to one or more terminals identifies them as being
associated with ranges that may, in normal use, be subjected to
particularly hazardous voltages. For maximum safety, the meter and its
test leads should not be handled when these terminals are energized.

This symbol indicates that a device is protected throughout by double
insulation or reinforced insulation.

SAFETY INSTRUCTIONS

This meter has been designed for safe use, but must be operated with caution. The rules
listed below must be carefully followed for safe operation.

1. NEVER apply voltage or current to the meter that exceeds the specified maximum:

Input Protection Limits

Function Maximum Input

V DC or V AC 600V AC and DC

mA AC/DC 200mA DC/AC

A AC/DC 10A DC/AC (for 30 seconds max. every 15 mins.)

Resistance, Diode Test, Continuity 250V DC/AC

2. USE EXTREME CAUTION when working with high voltages.

3. DO NOT measure voltage if the voltage on the "COM" input jack exceeds 600V above earth ground.

4. NEVER connect the meter leads across a voltage source while the function switch is in the current,
resistance, or diode mode. Doing so can damage the meter.

5. ALWAYS discharge filter capacitors in power supplies and disconnect the power when making resistance
or diode tests.

6. ALWAYS turn off power and disconnect test leads before opening the covers to replace the fuse or battery.

7. NEVER operate the meter unless the back cover and the battery and fuse covers are in place and fastened
securely.

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

WARNING

CAUTION

MAX
600V

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Model EX310 - Version 7.1 – 05/2006

3

Controls and Jacks

1. AC Voltage Detector Sensor

2. AC Voltage Detector indicator light

3. LCD display

4. Non-contact AC Voltage Detector test button

5. Rotary function dial

6. 10 ampere test lead jack

7. COM test lead jack

8. Test lead jack for voltage, milliamp,
resistance/continuity, and diode functions

9. Protective rubber holster (must be removed to
access the rear battery compartment)

Symbols

•))) Continuity

Diode

Battery status

AC

DC

m milli (10

-3

) (volts, amps)

k kilo (10

3

) (ohms)

V Volts

A Amps

Ω Ohms

AC Alternating current

DC Direct current

V/ /mA

CATII-600V

EX310

MultiMeter

1

2

3

4

5

6

7

8

9

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Model EX310 - Version 7.1 – 05/2006

4

Operating Instructions

WARNING: Risk of electrocution. High-voltage circuits, both AC and DC, are very

dangerous and should be measured with great care.

NOTE: On some low AC and DC voltage ranges, with the test leads not connected to a

device, the display may show a random, changing reading. This is normal and is caused
by the high-input sensitivity. The reading will stabilize and give a proper measurement
when connected to a circuit.

NON-CONTACT AC VOLTAGE DETECTOR

The EX310 can detect the presence of AC voltage (from 100 to 600VAC) simply by being
held very near to a voltage source.

WARNING: Test the AC voltage detector on a known live circuit before each use.

WARNING: Before using the meter in the AC Voltage Detector mode, verify that the battery

is fresh by confirming characters appear on the LCD when the function dial is turned to any
position. Do not attempt to use the meter as an AC Voltage Detector if the battery is weak
or bad.

NON-CONTACT VOLTAGE (NCV)

The NCV function works on any rotary switch position.

1. Test the detector on a known live circuit before use.

2. Press and hold the NCV button for the duration of the

test. The meter will beep once when the button is pushed.

3. Hold the top of the meter very close to the voltage source

as shown.

4. If voltage is present, the rim of the LCD display will flash

a bright orange and an audible warning will sound.

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Model EX310 - Version 7.1 – 05/2006

5

AC VOLTAGE MEASUREMENTS

WARNING: Risk of Electrocution. The probe tips may

not be long enough to contact the live parts inside some
240V outlets for appliances because the contacts are
recessed deep in the outlets. As a result, the reading may
show 0 volts when the outlet actually has voltage on it.
Make sure the probe tips are touching the metal contacts
inside the outlet before assuming that no voltage is
present.

CAUTION: Do not measure AC voltages if a motor on

the circuit is being switched ON or OFF. Large voltage
surges may occur that can damage the meter.

1. Set the function switch to the 600 VAC position.

2. Insert the black test lead banana plug into the

negative COM jack. Insert red test lead banana
plug into the positive V jack.

3. Touch the black test probe tip to the neutral side of the circuit.

4. Touch the red test probe tip to the “hot” side of circuit.

5. Read the voltage in the display.

DC VOLTAGE MEASUREMENTS

CAUTION: Do not measure DC voltages if a motor on the circuit is being switched ON or

OFF. Large voltage surges may occur that can damage the meter.

1. Set the function switch to the highest VDC position.

2. Insert the black test lead banana plug into the

negative COM jack.

Insert the red test lead banana plug into the

positive V jack.

3. Touch the black test probe tip to the negative side

of the circuit. Touch the red test probe tip to the
positive side of the circuit.

4. Read the voltage in the display. Move the function

switch to successively lower VDC positions to
obtain a higher resolution reading.

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