Yokogawa 2406E Operating Manual

User’s
Manual

2406E Series
Insulation Tester

Thank you for purchasing the YOKOGAWA 2406E Insulation Tester.
To optimize all the functions of the instrument, please read this manual thoroughly before operating it.

- Model ­2406 31 2406 33 2406 35

2406 41 2406 43 2406 45
2406 32 2406 34

2406 42 2406 44

Yokogawa Meters & Instruments Corporation
International Sales Dept.

Tachihi Bld. No.2, 6-1-3, Sakaecho, Tachikawa-shi,Tokyo 190-8586 Japan
Phone: [phone], Facsimile: 81-42-534-1426

YOKOGAWA CORPORATION OF AMERICA (U.S.A.)

Phone: [phone] Facsimile: 1-770-251-2088

YOKOGAWA EUROPE B. V. (THE NETHERLANDS)

Phone: [phone] Facsimile: 31-334-64-1610

YOKOGAWA ENGINEERING ASIA PTE. LTD. (SINGAPORE)

Phone: [phone] Facsimile: 65-6241-2606

YOKOGAWA AMERICA DO SUL S. A. (BRAZIL)

Phone: [phone] Facsimile: 55-11-5681-1274

YOKOGAWA MEASURING INSTRUMENTS KOREA CORPORATION (KOREA)

Phone: [phone] to -0664 Facsimile: 82-2-551-0665

YOKOGAWA AUSTRALIA PTY. LTD. (AUSTRALIA)

Phone: [phone] Facsimile: 61-2-9888-1844

YOKOGAWA INDIA LTD. (INDIA)

Phone: [phone] Facsimile: 91-80-2852-1441

YOKOGAWA SHANGHAI TRADING CO., LTD. (CHINA)

Phone: [phone] Facsimile: 86-21-6880-4987

YOKOGAWA MIDDLE EAST E. C. (BAHRAIN)

Phone: [phone] Facsimile: 973-336100

LTD. YOKOGAWA ELECTRIC (RUSSIAN FEDERATION)

Phone: [phone] Facsimile: 7-095-737-7869

IM3E-2006.2

6th Edition : Jun. 2006 (KP)
All Rights Reserved, Copyright © 1996, Yokogawa M&C Corporation

IM 2406E-E
7th Edition July 2007

1. Regarding Safe Use of This Product

■ For the safe use of this product, the following safety symbols are used on the product concerned:

WARNING

CAUTION

■ Always observe the following instructions. Failure to observe these instructions may result in electric

shock hazards or other dangers that may lead to serious injury or the loss of life.

■ Always observe the following instructions. Failure to observe these instructions may result in electric

shock hazards or other dangers that may lead to injury or damage to the instrument.

■ Measurement Categories

Measurement category

1

2

3

4

Danger! Handle with Care.
This symbol indicates that the operator must refer to an explanation in the user’s manual in order to avoid
risk of injury or death of personnel or damage to the instrument.
High-voltage Terminal
This symbol indicates a dangerous level of voltage (terminals fed from the interior by voltages exceeding
1000 volts must be so marked). Never touch the terminal.
AC Voltage
This symbol indicates that an AC voltage is present.
This indicates on the product that the operator must refer to an explanation in the user’s manual in order to
avoid the risk of serious injury or death of personnel. The manual describes how the operator should exercise
special care to avoid electric shock or other dangers that may result in serious injury or the loss of life.
This indicates on the product that the operator must refer to an explanation in the user’s manual in order to
avoid the risk of injury or damage to the product. The manual describes how the operator should exercise
special care to avoid dangers that may result in injury or damage to the instrument.

WARNING

1. During Measurement of Insulation Resistance

•A high voltage is present at the probes. Do not touch the device under test (DUT) or the EARTH, LINE or GUARD
terminal.

2. During Measurement of AC Voltages

•Do not press the MEAS key while measuring AC voltages.

•An AC voltage is present at the GUARD terminal. Do not touch the terminal.

3. Immediately After Measurement of Insulation Resistance

• The probes or DUT may remain highly charged. Do not touch them immediately after the completion of measure­ment.

4. Probes

•Use the probes supplied with this tester by Yokogawa Meters & Instruments.

•Do not use probes that have deteriorated or broken.

•Remove the probes from the DUT before attaching/detaching the probes to/from the tester.

5. Insulation of Casing

• Punctures in the protective insulation may occur if there are any cracks or other damage in the casing as a result of
the instrument having been dropped or hit against other objects. Do not use the instrument before any remedial
measures are taken; ask the manufacturer for repair.

6. DUTs

• Turn off electrical power to the DUT before you begin measuring insulation resistance.

•Avoid touching any electrified part while using the tester around electrically live locations. For safety, it is recom­mended that you use a pair of rubber gloves or other alternative means.

7. Battery Replacement

•Remove the probes from the DUT and then turn off the range selector switch before you open the casing to replace
the batteries.

•Do not touch the MEAS key during replacement. Otherwise, a high voltage may be produced.

8. Operating Environment

•Do not operate the tester in an atmosphere where any flammable or explosive gas is present.

•Do not use the tester if there is condensation on it.

9. Disassembly

•

No person, except service personnel from Yokogawa Meters & Instruments, is authorized to disassemble this instrument.

CAUTION

1. Measurement of AC Voltages

•Do not apply any voltage between terminals that exceeds the specified limit.

2. GUARD Terminal

• The GUARD terminal is an auxiliary measurement terminal to eliminate a leakage current. Do not apply any testing
voltage to the terminal.

3. Ranges

•Do not switch between the rated voltages until two to three seconds have elapsed after the completion of each
measurement. Switching between voltages immediately after the completion of measurement may result in pos­sible damage to the tester or DUT due to the electrical charge at the probes or DUT. Note that the tester is provided
with a discharge feature.

4. Power to DUTs

• Electrical charges may be present at metals or wiring cables attached to electrical equipment being tested. Verify
that the equipment is free from electrical charges before connecting the testing terminals. The same rule applies to
the grounding wire.

5. Range Selector Switch

•Do not operate the range selector switch during testing.

•Do not apply any voltage to the testing terminals when measuring insulation resistance.

6. Batteries

•Do not mix batteries of different types or new batteries with used ones. If the tester will not be in service for a
prolonged period, always remove the batteries before you store the instrument. If you store the tester with the
batteries left installed, they are more likely to suffer fluid leakage, resulting in a malfunctioning of the instrument.

Description
For measurements performed on circuits not directly connected to MAINS.

CAT.1

For measurements performed on circuits directly connected to the low voltage installation.

CAT.2

For measurements performed in the building installation.

CAT.3

For measurements performed at the source of the low-voltage installation.

CAT.4

Remarks

Appliances, portable equipments, etc.
Distribution board, circuit breaker, etc.
Overhead wire, cable systems, etc.

A3

2. Components and Their Functions

➄ Line

terminal

➅ Earth

terminal

➀ Indicator

window

➂ MEAS key

➆ Guard

terminal

➁ Range

➈ Bottom

selector
switch

➇

➃ LIGHT key

Indicator window
Range selector switch
Used to switch between the ranges for measuring insulation resistance and to select the OFF position (battery check).
MEAS key
Used for insulation resistance measurements and battery checks.
LIGHT key
Used to turn the lamp for the indicator window on or off.
Line terminal
Earth terminal
Guard terminal
Bottom cover
Bottom cover setscrew
Used to replace batteries.

3. Measuring the Insulation Resistance

• Connecting the Probes

WARNING

Securely plug the line probe into the LINE terminal and the earth probe into the EARTH terminal.

• Disconnecting the Probes

1. Make sure the range selector switch is off.

2. Unplug the respective probes.

• Measuring the Insulation Resistance

1. Adjust the range selector switch to the voltage (rated voltage) to be applied to the DUT.

2. If the DUT is grounded, connect the earth probe clip to the DUT's ground line. If the DUT is not grounded, the earth
probe clip may or may not be connected to the DUT's ground line.

3. Bring the line probe into contact with the DUT, and then press the MEAS key. The pointer then indicates the insulation
resistance of the DUT. During measurement, exercise care to prevent the leadwire of the line probe from coming into
contact with the ground, floor or other object. Not observing this precaution may result in a failure to measure the correct
insulation resistance.
Upon completion of measurement, always turn the range selector switch off.

4. Immediately after measurement, electrical charges resulting from the applied testing voltage may be present at the probes or
DUT. The tester, therefore, is designed to automatically begin discharging electricity upon completion of measurement.

• Discharge Feature

Any capacitive component in the DUT will be charged during measurement and thus the DUT remains electrified even after
the completion of measurement, resulting in a hazardous condition.
The tester is designed to begin discharging when the MEAS key is turned off. The pointer then swings to the position on the
scale proportional to the voltage that has developed across the terminals. After measurement is completed, leave the probes
connected until the pointer swings back to the infinity sign (•) to allow the electricity in the DUT to fully discharge.

• Locking the MEAS Key

WARNING

The MEAS key, when pulled up to the right, can be locked with the key left turned on. Use this mechanism when making
continuous measurement over a prolonged period. Note, however, that leaving the key turned on for an unreasonably long time
will accelerate the discharge of the batteries.

• Measuring Only the Volumetric Resistance

For example, assume that you are doing an insulation test on a cable, as
shown in the figure on the right.
If you bring a lead (optional) connected to the GUARD terminal into con­tact with an insulator overlapped by bare conducting wire, you can measure
the volumetric resistance only. This is because the leakage current that
flows along the surfaces of the insulator does not flow into the indicator. A
dedicated lead (part number: 321803) is necessary when using the GUARD
terminal.

Item 4

WARNING

Item 1

Item 4

WARNING

WARNING

Items 1, 3 and 6;

Item 1;

CAUTION

Main unit

CAUTION

Items 2 and 4

Indicating
meter

Power
supply

Items 3, 4 and 5

LINE

GUARD

EARTH

Core wire
Bare conducting wire
Insulator

Metal cladding

cover
setscrew

Bottom

cover

Entrance
Cable

CAT.4

Internal Wiring

Distribution
Board

CAT.1

Fixed Equipment,
etc.

CAT.3

CAT.2

T

Equipment

Outlet

IM 2406E-E <1>

4. Measuring AC Voltages

WARNING

Items 2 and 6;

CAUTION

Items 1 and 5

The tester can also measure commercial-frequency AC voltages. When measuring insulation resistance, also use the tester
to verify that there is no voltage present at the DUT.

1. Plug the probes in the same way as when measuring insulation resistance.

2. Bring the line probe into contact with the location at which the AC voltage is being measured. Read the value on the
voltage measurement scale (AC V). While you are measuring AC voltages, do not press the MEAS key.

5. Other Functions

• Lighting Up the Indicator Window (models 240641, 42, 43, 44 and 45 only)

Press the LIGHT key to turn on the scale plate lamp. Press the key once again to turn the lamp off. The lamp automatically
turns off approximately 40 seconds after it has turned on.

6. Battery Check

1. Turn the range selector switch off and then press the MEAS key.

2. The batteries are still operable if the pointer is indicating anywhere within the range for a battery check (B mark).

3. The batteries are low if the pointer fails to stay within the range. Replace the batteries by following the instructions given
in Section 7 below.

7. Battery Replacement

WARNING

Item 7;

CAUTION

Item 6

1. Make sure that the range selector switch is off.

2. Loosen the bottom cover setscrew with a coin or the like, and then slide the cover off of the main unit.

3. Remove all six batteries at one time and insert new ones with their polarities set exactly as shown on the battery holder.

4. After changing the batteries, replace the bottom cover and tighten the setscrew.

8. Maintenance

■ Storage Conditions

• Temperature/humidity: -10 to 60˚C/70%RH maximum

•Avoid storing the tester in a location where there is:

moisture,

• exposure to direct sunlight,

•a high-temperature heat source nearby,

• exposure to severe mechanical vibrations,

•a large amount of dust and/or salt, or

•a corrosive gas.

■ Removal of Dirt

Do not use volatile solvents (such as paint thinners or benzine) as they are likely to cause discoloration. Wipe off dirt with a
cloth dampened water or alcohol.

Battery :R6, AA 1.5 V (6 batteries)
External dimensions :Approx. 120 ⫻ 110 ⫻ 60mm
Weight :Approx. 500g (including batteries)
Safety Standard :Complied Standard BS EN61010-1

BS EN61010-2-31
Insulation class II Double insulation
Measurement category II
Polution degree 2

EMC Standard :Complied Standard EN55011 Group1 Class A

EN61326

CAUTION

This product is class A for use in an industrial environment and may cause radio
interference if used for domestic use.
Therefore, appropriate measures must be taken when using it for domestic use.

Note

•The application of the following accessory could affect the safety and EMC performance of the product and such
item should be used with this consideration.

- Lead for guard terminal : 321803

• Interconnection with other apparatus is not recommended.

Supplied Accessories (the items labeled

Description Model/PartNo. Qt'y Remarks

Batteries R6P 6 Built-in (AA-size)
Earth and
Line probe

➀ Line probe B9204XD
➁ Earth probe B9204XJ

➂ Hard case B9075UF (including a probe case)

User’s manual IM2406E-E 1 This manual

98007

to are spare parts)

➀

➂

➁

■ External Dimensions

120 53

■ Calibration Cycle

It is recommended that the tester be calibrated once every year for correct operation; ask Yokogawa Meters & Instruments to
do the periodic calibration for you.

9. Specifications

●

Insulation Resistance (Standard Test Conditions: Ambient Temperature = 23 ± 5˚C; Relative Humidity = 45-75%)

Model Rating Central scale First effective Second effective measuring Low limit measuring Rated current AC-Voltage

240631 25 V/5MΩ 0.1MΩ 0.005-2MΩ 2MΩ (exclusive)-5MΩ 0.025MΩ 1 mA 0-300 V
240641* 50 V/10MΩ 0.2MΩ 0.01-5MΩ 5MΩ (exclusive)-10MΩ 0.05MΩ 1 mA

125 V/20MΩ 0.5MΩ 0.02-10MΩ 10MΩ (exclusive)-20MΩ 0.125MΩ 1 mA

240632 125 V/20MΩ 0.5MΩ 0.02-10MΩ 10MΩ (exclusive)-20MΩ 0.125MΩ 1 mA 0-300 V
240642* 250 V/50MΩ 1MΩ 0.05-20MΩ 20MΩ(exclusive)-50MΩ 0.25MΩ 1 mA

240633 125 V/20MΩ 0.5MΩ 0.02-10MΩ 10MΩ (exclusive)-20MΩ 0.125MΩ 1 mA 0-600 V
240643* 250 V/50MΩ 1MΩ 0.05-20MΩ 20MΩ (exclusive)-50MΩ 0.25MΩ 1 mA

500 V/100MΩ 2MΩ 0.1-50MΩ 50MΩ (exclusive)-100MΩ 0.5MΩ 1 mA

240634 250 V/50MΩ 1MΩ 0.05-20MΩ 20MΩ (exclusive)-50MΩ 0.25MΩ 1 mA 0-600 V
240644* 500 V/100MΩ 2MΩ 0.1-50MΩ 50MΩ (exclusive)-100MΩ 0.5MΩ 1 mA

1000 V/2000MΩ 50MΩ 2-1000MΩ 1000MΩ (exclusive)-2000MΩ 1MΩ 1 mA***

240635 250 V/500MΩ 10MΩ 0.5-200MΩ 200MΩ (exclusive)-500MΩ 0.25MΩ 1 mA*** 0-600 V
240645* 500 V/1000MΩ 20MΩ 1-500MΩ 500MΩ (exclusive)-1000MΩ 0.5MΩ 1 mA***

1000 V/2000MΩ 50MΩ 2-1000MΩ 1000MΩ (exclusive)-2000MΩ 1MΩ 1 mA***

Standard test conditions

Ambient temperature and humidity : 23 ±5˚C at 45 to 75% RH
Attitude : Horizontal (within 5 degrees from horizontal)
Influence of earth magnetism : Earth magnetic field
Battery Voltage : Within effective range for the battery (When the battery is checked, the pointer must

Tolerances under the above conditions

Resistance measurement : ±5% of reading within the first effective measuring range

Infinity and zero indications : Up to 0.7% of scale length
AC voltage : ±10% of the maximum value
No load voltage : Within 130% of the rated voltage
Rated measuring current : 1 mA for the first effective measuring range (-0 to +20%)
Short-circuit current : 12 mA or less

Scale length :Approx. 86 mm
Response time :3 sec or less untill the pointer is within tolerance from the instant the resistors whose

Friction :No friction is recognized.
Effects of tilting :Deviation from the infinity indication when the tester is tilted or rotated by 30 degrees

Effect of temperature :Deviation from the midpoint indication at 20˚C must be 5% or less when ambient

Effect of humidity :Within tolerance when the tester is left for one hour with the humidity at 90% RH.
Effect of external magnetic field :The change of indication must be 3% or less of the indicated value when an external

Effect of AC component of voltage at measurement terminals :

Insulation resistance : 50M

Dielectric strength : 3700 V AC for one minute between the electric circuits and the outer case.
Vibration proof :When a vibration frequency of 16.7 Hz and peak-to-peak amplitude of 4 mm are

Shock proof :When shock of 1000 m/s

Durability :When a resistor corresponding to the midpoint indication is connected across the mea-

Input mistake protection :When an AC voltage of 50 or 60Hz at 1.2 times the rated measuring voltage is applied

Operation temperature/humidity :0 to 40˚C/90%RH or less (no condensing)
Storage temperature/humidity : -10 to 60˚C/70%RH or less (No condensing; remove the battery).

mark measuring range range resistance** measuring range

*: denotes models with a scale plate lamp
** : denotes a value that allows the rated voltage to be maintained during testing
*** : indicates that the value becomes 0.55 mA at the lower limit of the primary effective range of measurement.

be within the B mark)

±10% of reading within the second effective measuring range

values correspond to the midpoint and zero indications are connected abruptly.

from the horizontal must be 2% or less of the scale length.

temperature is varied from 20˚C by ±20˚C.

0.7% or less of scale length for infinity and zero indications.

field of DC 400A/m is applied in the most affected direction.

A change when a capacitor of 5µF ±10% is connected in parallel with a resistor corre­sponding to the midpoint indication connected, must be 10% or less of indication.

Ω

or more between electric circuits and outer case, when tested at 500V if the
rated measuring voltage is 500 V or less and at a voltage identical to the rated voltage
if the rated voltage exceeds 500 V.

applied to the direction of the axis of the moving part, the specifications for toler­ances, friction, and the effect of tilting must be met.

2

is applied twice in the direction of axis of the moving part
and the direction perpendicuar to the axis, specifications for tolerance, friction, and
effect of tilting must be met.

suring terminals and the power switch is repeatedly turned on and off 10,000 times at
the rate of about 300 times/hour, the specifications for tolerance and friction must be
met.

to the measuring terminals for 10 seconds, no abnormality must occur.

110

■ Notice Regarding The Manual

• The information contained in this manual is subject to change without notice.

• Every effort has been made to ensure that the information contained herein is accurate.
However, should any concerns, errors, or omissions come to your attention, or if you have any comments, please contact us.

• The contents of this manual may not be transcribed or reproduced, in part or in their entirety, without prior permission.

IM 2406E-E <2>