Instruction manualHigh voltage insulation resistance tester

KEW3121B/3122B

Contents
1. Safety warnings .................................................................... 1
2. Features ............................................................................... 5
3. Specification ......................................................................... 6
4. Instrument layout .................................................................. 9
5. Getting started ................................................................... 10
5-1 Mechanical Zero Adjustment ........................................ 10
5-2 Battery Check ............................................................... 10
6. Measurement ..................................................................... 11
6-1 Insulation resistance measurement ............................. 11
6-2 Continuous measurement ............................................ 13
6-3 Voltage characteristics at measuring terminal .............. 13
6-4 Use of Guard terminal .................................................. 14
7. Battery replacement ........................................................... 15
8. How to remove the Hard case ............................................ 16
9. Cleaning Meter Cover ........................................................ 17
10. Accessories ...................................................................... 18
10-1 Metal parts for Line Probe, and replacement ............ 18
10-2 How to use the adaptor for recorder ......................... 19
10-3 Line probe with alligator clip(optional accessory) ...... 19
11. Disposing the Product ....................................................... 20

1. Safety warnings○T his instrument has been designed, manufactured and tested
according to IEC 61010: Safety requirements for Electronic
Measuring apparatus, and delivered in the best condition after
passing quality control tests. This instruction manual contains
warnings and safety rules which must be observed by the user
to ensure safe operation of the instrument and to maintain it insafe condition. Therefore, read through these operating
instructions before using the instrument.
# WARNING● Read through and understand instructions contained in thismanual before starting to use the instrument.
● Keep the manual at hand to enable quick reference whenevernecessary.
● The instrument is to be used only in its intended applications.
● Understand and follow all the safety instructions contained in
the manual. It is essential that the above instructions areadhered to.
F ailure to follow the above instructions may cause injury,
instrument damage and/or damage to equipment under test.
○The symbol # indicated on the instrument means that the user
must refer to the related parts in the manual for safe operationof the instrument. It is essential to read the instructions wherever
the symbol # appears in the manual.
# DANGER	is reserved for conditions and actions that arelikely to cause serious or fatal injury.
# WARNING is reserved for conditions and actions that cancause serious or fatal injury.
# CAUTION	is reserved for conditions and actions that cancause injury or instrument damage.
−1−

# DANGER●D o not use this instrument to test the circuits in which 300Vor higher potentials exist in Measurement category IV (CATIV) environment or 600V or higher potentials exist in CAT III
environment.
●D o not attempt to make measurements in the presence offlammable gasses. Otherwise, the use of the instrument may
cause sparking, which can lead to an explosion.
●N ever attempt to use the instrument if its surface or yourhand is wet.
●B
 e careful not to short-circuit the power line with the metal
part of the test leads when measuring a voltage. It may
cause personal injury.
●D o not exceed the maximum allowable input of any measuring
ranges.
●D o not press the Test button when connecting the test leads
to the instrument.
●N ever open the Battery compartment cover during ameasurement.
●T o prevent possible electrical shock, do not touch the circuitunder test during an insulation resistance measurement orright after a measurement.
# WARNING● Never attempt to make any measurements if any abnormal
conditions such as broken case and exposed metal parts arenoted.
● Do not rotate the Function switch with the test leads
connected to the object under test.
● Do not install substitute parts or make any modifications to
the instrument. Return the instrument to your local
KYORITSU distributor for repair or re-calibration.
● Do not try to replace the batteries if the surface of the
instrument is wet.
● Insert the plug into the terminal firmly when using test leads.
● Ensure that the instrument is switched off before opening theBattery compartment cover for battery replacement.
−2−

# CAUTION● Before starting a measurement, confirm that the Function
switch is at an appropriate position.
● Set the Function switch to “OFF” position after use. Remove
the batteries if the instrument is to be stored and will not be
in use for a long period.
● Do not expose the instrument to direct sunlight, high temperatures and humidity or dew.
● Use a damp cloth with alcohol for cleaning the instrument
and the areas around the measuring terminals.
● When this instrument is wet, please store it after it dries.
Symbols

 Danger of possible electric shock Instrument with double or reinforced insulation
 User must refer to the manual
 DC
 AC
 Earth terminal
Crossed-out wheel bin symbol (according to WEEE
Directive: 2002/96/EC) indicating that this electrical
product may not be treated as household waste, but thatit must be collected and treated separately.

−3−

○ Measurement categories (Over-voltage categories)
To ensure safe operation of measuring instruments, IEC 61010
establishes safety standards for various electrical environments,
categorized as O to CAT IV, and called measurement categories.
Higher-numbered categories correspond to electrical environmentswith greater momentary energy, so a measuring instrument
designed for CAT III environments can endure greater momentaryenergy than one designed for CAT II.
O: Circuits which are not directly connected to the mains
power supply.
CAT II : Electrical circuits of equipment connected to an ACelectrical outlet by a power cord.
CAT III : Primary electrical circuits of the equipment connected
directly to the distribution panel, and feeders from the
distribution panel to outlets.
CAT IV : T
 he circuit from the service drop to the service
entrance, and to the power meter and primary
overcurrent protection device (distribution panel).

O: Device which is
not directly
connected to themains power supply−4−

2. Features
KEW3121B (2500V/100GΩ) and KEW3122B (5000V/200GΩ)are battery-operated high voltage insulation testers.
● Designed to meet the following safety standards:
IEC 61010-1,-2-030 (CAT III 600V/CAT IV 300V Pollution
degree 2)
IEC 61010-031 (Requirements for hand-held probes)● Suited for heavy duty electrical maintenance and servicing
ofindustrial installations, cables, transformers, generators andswitchgear where high voltage insulation tests are required.
● Dual scales for low an d high ranges which change automatically.
C olour coded scales for easy reading plus LED's that illuminate
in matching colour.
● Hard carrying case furnished as standard accessory. Houses
both instrument and test leads in compact form. Made ofplastic, it is highly water resistant.
● Rated output voltage is maintained down to 0.1GΩ for
KEW3121B, 0.2GΩ for KEW 3122B. This permits accurate
measurements of low insulation resistance.
●A udible high voltage warning at insulation resistance measurement● Optional adapter MODEL8324 is available for connection torecorder and enables cable insulation monitoring.(Option)−5−

3. Specification● Applicable standards
IEC 61010-1,-2-030
		
Measurement CAT III 600V Pollution degree2
		Measurement CAT IV 300V Pollution degree2
IEC 61010-031 Standard for hand-held probes
		
MODEL7165A(CAT IV 600V)
		
MODEL7264(CAT IV 600V)
		
MODEL7265(CAT IV 600V)
		* When KEW3121B/3122B and the test leadare combined and used together, whicheveris lower category either of them belongs to isapplied.
IEC 61326-1,-2-2 EMC standard
IEC 60529
IP40
EN 50581
RoHS Directive● Measuring range and accuracy
Model
KEW3121B
KEW3122B
Rated voltage
2500V
5000V
0 - 2GΩ/ 1 - 100GΩ
0 - 5GΩ/ 2 - 200GΩ
Measuring range(Automatic change)(Automatic change)
First effective
0.1 - 50GΩ
0.2 - 100GΩ
measuring range
Temperature: Accuracy±5% of indicated value
Second effective Measuring ranges other than listed above , 0 and ∞23ºC±5ºC
measuring range
Accuracy±10% of indicated value or 0.5% of scale length
First effective
0.1 - 50GΩ
0.2 - 100GΩ
measuring range
Temperature: Accuracy±10% of indicated value-10ºC to +40ºC Second effective Measuring ranges other than listed above , 0 and ∞measuring range
Accuracy±20% of indicated value or 1.0% of scale length
DC 2500V±5%
DC 5000V±5%
Output voltage(0.1 - 50GΩ)(0.2 - 100GΩ)−6−

●Altitude : 2000m or less
●Temperature & humidity range(guaranteed accuracy): 23ºC±5ºC/Relative humidity 85% or less (no condensation)●Operating temperature & humidity range: -10ºC to +40ºC/Relative humidity 85% or less (no condensation)●Storage temperature & humidity range: -20ºC to +60ºC/Relative humidity 75% or less (no condensation)●Overload protection : Insulation resistance range: AC720V/10sec.
●Withstand voltage: AC5160V(50/60Hz)/ 5 sec.
(Between electrical circuit and enclosure)●Insulation resistance : 1000MΩ or more/DC1000V(Between electrical circuit and enclosure)●Dimension: 177(L)×226(W)×100(D)mm●Weight: KEW3121B approx. 1.6kg (battery included)
KEW3122B approx. 1.7kg(battery included)●Power source: DC12V LR14(Alkaline battery size C)x 8pcs
●Current consumption (representative values at supply voltage 12V)
Model
Rated voltage
Short-circuit current
Max. current
consumption
Output at
open circuit●Measurement time

KEW3121B
2500V
65mA
80mA
/50MΩ

KEW3122B
5000V
82mA
100mA
/100MΩ

70mA

85mA

: 3121B:approx. 55 hours*under a load of 50MΩ on the Insulation
resistance 2500V range.
3122B:approx. 40hours*under a load of 100MΩ on the Insulation
resistance 5000V range.

−7−

●Accessories
		
		
		
		
		
		
		
		
●Optional
accessories		: Line probe: MODEL 7165A
(Including MODEL8255 Straight type prod
with molded parts)
Earth cord: MODEL 7264
Guard cord: MODEL 7265
LR14(Alkaline battery size C)x 8pcs
Instruction manual
Hard Case: MODEL 9179
Pickel Type Prod: MODEL 8019
Straight Type Prod: MODEL 8254
: Adaptor for recorder:MODEL8324
3m Line probe with alligator clip: MODEL7168A
15m Line probe with alligator clip: MODEL7253−8−

4. Instrument layout
3

5

2

1

7

4

6

1 Line terminal
2 Guard terminal
3 Earth terminal
4 LED for high & low range indication
5 PRESS TO TEST button
6 Function switch
7 Meter movement zero adjust
8 Guard cord (green)
9 Earth cord (black)
10 Line probe

−9−

8

9

10

5. Getting started# DANGER●B
 e careful. High voltage may present across LINE andEARTH terminals of the instrument when the PRESS TOTEST button is operated. Make sure to connect the Earthterminals of the circuit under test and of this instrument toearth. The buzzer sounds continuously while measuring
insulation resistance.
5-1 Mechanical Zero Adjustment
S et the Function switch to “OFF” position. Adjust the Meter
movement zero adjust located at the center of the Front
panel with a screwdriver so that the pointer of the instrument
reads “∞“ symbol on the scale.
5-2 Battery CheckS et the Function switch to “BATT. CHECK” position and press
the PRESS TO TEST button. The battery voltage is enoughwhen the the pointer stays in BATT. GOOD area or to theright of this area.
If not, replace the batteries with new ones.

NG

OK# DANGER●D o not hold down or lock the PRESS TO TEST button whenchecking the battery voltage. It may lead to shorter battery life.
− 10 −

6. Measurement
6-1 Insulation resistance measurement# DANGER●U se a high voltage detector and confirm that there is noelectrical charge in the circuit under test.
● Wear a pair of insulated gloves for high voltage.
● If the Function switch is at the insulation resistance range
and the Test button is being pressed down, high voltages are
generated and applied to the test leads and the circuit under
test continuously. Do not touch the circuit or the test leads.
●T he Battery compartment cover must be closed and screwed
during a measurement.
● Do not make measurement when thunder rumbling.
●C onnect the Earth Cord (black) to the earth terminal of thecircuit under test.
This instrument measures insulation resistances and checks
whether the insulations of electrical equipments or circuits are ingood condition or not. So, please check the voltage that can beapplied to the object under test before making a measurement.
Note:●The insulation resistance values of the objects under test may
not be stable, and the readings may be unstable.
●Bleep sound may be heard during an insulation resistancemeasurement, but it is not malfunction.
●It takes time to measure a capacitive load.
●At insulation resistance measurement, positive (+) voltage is
outputted from the Earth terminal and negative (-) voltage is
outputted from the Line terminal.
Connect the Earth cord to the Earth (ground) terminal.
It is recommended to connect the positive(+) pole to the earthside when measuring insulation resistance against the groundor when a part of the equipment under test is earthed.
W ith this connection, smaller measured value can be obtained
comparing with other way round.
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(1) Check the voltage which can be applied to the circuit under
test, and set the Function switch to a desired insulation
resistance range.
(2) Connect the Earth cord (black) to the Earth terminal of thecircuit under test.
(3) Place the tip of the Line probe (red) to the circuit under test.
T hen press the “PRESS TO TEST” button. The buzzer sounds
intermittently during a measurement.
(4) When the green LED illuminates, read insulation resistanceon the outer scale (for high range). Use the inner scale where
the red LED illuminates.

# Caution
Always turn off the
Breaker for the circuitunder test.

(5) A fter a test, release the PRESS TO TEST button and wait forthe same amount of time that it took for the measurement
performed. Keep the Line probe and the circuit tested
connected until electrical charges stored in the circuit under
test are completely discharged.
# DANGER●D o not touch the circuit under test immediately after testing.
Capacitances stored in the circuit may cause electric shock.
●L eave the test leads connected to the circuit and never touch
the circuit until electrical discharge completes.
(6) Set the Function switch to “OFF” position, and disconnect thetest leads from the instrument.
− 12 −

6-2 Continuous measurement
P ress and turn the Test button clockwise and lock the button
to measure insulation resistances continuously. Turn the
button counter-clockwise and set it to the initial position after
a measurement.
# DANGER●B
 e extremely careful not to get electric shock as a highvoltage is present on the tip of the test leads continuously.
6-3 Voltage characteristics at measuring terminal
KEW3121B/ 3122B Output characteristics
6000

KEW3122B/
5000V

Output Voltage (V)

5000
4000
3000

KEW3121B/
2500V

2000
1000
0
0.001

0.01

0.1

1

Insulation Resistance (GΩ)− 13 −

10100

6-4 Use of Guard terminalW hen measuring the insulation resistance of a cable, leakage
current flowing on the surface of cable jacket and the current
flowing inside the insulator are mixed and may cause error ininsulation resistance value. In order to prevent such error,
wind a conductive wire around the point where leakage
current flows. Then connect it to the Guard terminal. This is
to move out the surface leakage resistance of the cableinsulation to measure only the volume resistance of insulator.
Make sure to use the Guard cord supplied with this instrument
to connect the instrument to Guard terminal.

* It is possible to move out the surface leakage resistance of theinsulation and measure only the volume resistance by using theGuard terminal. This is helpful when performing tests in humid
air.

− 14 −

7. Battery replacement# DANGER●D o not open the Battery compartment cover if the surface of
the instrument is wet.
●N ever open the Battery compartment cover during ameasurement. To avoid electric shock, power off the
instrument and disconnect the test leads from the instrument
when replacing batteries.
●A lways attach and close the Battery compartment coverwhen making a measurement.
# CAUTION● Do not mix new and old batteries or brands of batteries.
● Make sure to install batteries in correct polarity as marked
inside.
(1) Set the Function switch to “OFF” position, and disconnect thetest leads from the instrument.
(2) Loosen the Battery compartment cover-fixing screws, andremove the Battery compartment cover. Remove all eightbatteries and replace them with new ones.
(3) A fter replacing batteries, be sure to tighten up the screw for
the Battery compartment cover.
SCREW

Make sure to installbatteries in correct
polarity as marked
inside.

− 15 −

8. How to remove the Hard case
Hold the side surface of the terminal part, and gently pull the unit
toward the front.
1. Hold the side surface of the terminal part.

2. Pull the unit toward the front.

− 16 −

9. Cleaning Meter CoverThis instrument is managed by our company's quality standard
and is delivered in the best condition after passed the inspection.
But in the dry time of winter static electricity sometimes builds up
on the meter cover due to the characteristic of plastic.
When static electricity builds up on the meter cover and affects
the meter reading, use a cloth dampened with off-the-shelf antistatic agent or detergent to wipe the meter cover surface.
# CAUTION● When the pointer deflects by touching the surface of thistester or zero adjustment cannot be made, do not try to makemeasurements.
●A nti-static agent has been applied to the surface of the Meter
cover of this instrument. Clean the surface of the cover gently
when it gets dirty.
●T o avoid possible deforming or discoloring, do not use
organic solvents.

− 17 −

10. Accessories
10-1 Metal parts for Line Probe, and replacement# DANGER
Attach MODEL8255 to the test leads to use the instrument in
CAT II or higher environments. MODEL8254 and 8019 have
exposed large metal parts, therefore, they may short circuit ordamage the objects under test, cause fire or pose fatal or
serious injuries to the users.
(1) Tip metal partsM ODEL8255: Standard Prod (straight type, with molded
parts)
MODEL8254: Straight Type Prod
MODEL8019: Pickel Type Prod
To be used to hook the instrument.
(2) ReplacementT urn the Line probe counterclockwise to remove the attached
tip metal. Put the tip metal you want to use to the hexagon
socket and turn it clockwise together with the tip of probe,
and tighten up the screws.
MODEL8255
Male Screw

Hexagon Socket
MODEL8254

MODEL8019− 18 −

10-2 How to use the adaptor for recorderM ODEL8324 is an adaptor for a recorder (option) for output
current measurement. Connect it as shown in the below
figure.
Output is DC10mV when current of 1μA is flowing.

To shield
or Earth

To recorder－+10-3 Line probe with alligator clip(optional accessory)
MODEL7168A : 3m Line probe with alligator clip
MODEL7253 : 15m Line probe with alligator clip

− 19 −

11. Disposing the ProductWaste Electrical and Electronic Equipment (WEEE), Directive
2002/96/EC
This Product complies with the WEEE Directive (2002/96/EC)
marking requirement. The affixed product label (see below)
indicates that you must not discard this electrical/electronic
product in domestic household waste.
Product Category
With reference to the equipment types in the WEEE directive
Annex 1, this product is classified as a “Monitoring and Control
instrumentation” product.

Disposing lead-storage batteries
When you throw away the batteries, be sure to cover theirpositive and negative terminals and always observe local laws
and regulations.
Insufficient insulation of the terminals may cause explosion orfire because electrical energies remain in lead-storage batteries
after use.

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MEMO− 21 −

DISTRIBUTOR

Kyoritsu reserves the rights to change specifications or designs
described in this manual without notice and without obligations.

03-15

92-2236