Instruction Manual
KEW4105DL

KEW4105DLBT (Equipped Bluetooth)

Digital Earth Resistance Tester

KEW 4105DL/4105DLBTContents
1. Safety warnings ････････････････････････････････････････････1
2. Features ･･･････････････････････････････････････････････････5
3. Specifications ･･････････････････････････････････････････････6
4. Name of parts ･･････････････････････････････････････････････9
5. Accessories ･･････････････････････････････････････････････ 12
6. Getting started ･･･････････････････････････････････････････ 15
7. Earth resistance measurement ･････････････････････････････ 16
7-1. Measurement principle･･･････････････････････････････ 16
7-2. Precision measurement (with test leads for precision
measurement) ･･････････････････････････････････････ 16
7-3. Simplified measurement (with test leads for simplified
measurement) ･･････････････････････････････････････ 20
8. Comparator function ･･････････････････････････････････････ 23
8-1. Comparator function ････････････････････････････････ 23
8-2. How to enable/ disable comparator function ･･････････ 24
9. Switching indications of aux. earth resistance warning ･･･････ 25
10. Backlight ･･･････････････････････････････････････････････ 25
11. Bluetooth communication function (KEW 4105DLBT only) ･･ 26
11-1 Bluetooth communication ･･･････････････････････････ 26
11-2 Features of KEW Smart*(asterisk) ････････････････････ 27
12. Battery replacement ･････････････････････････････････････ 28
13. Cleaning ････････････････････････････････････････････････ 29
14. Notes on housing case ･･･････････････････････････････････ 30
15. How to fit strap belt ･･････････････････････････････････････ 31
16. Cable reels ･････････････････････････････････････････････ 31
16-1. Operating instruction ･･･････････････････････････････ 31
16-2. Cable replacement ････････････････････････････････ 32

1．Safety warnings
This 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 have to be observed by the user
to ensure safe operation of the instrument and to maintain it in safe
condition. Therefore, read through these operating instructions before
starting to use the instrument.
# DANGER● Read through and understand the 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 are adhered to. Failure
to follow the above instructions may cause injury, instrument
damage and/or damage to equipment under test. Kyoritsu is by
no means liable for any damage resulting from the instrument incontradiction to these cautionary notes.
The symbol # indicated on the instrument, means that the user
must refer to the related parts in the manual for safe operation of the
instrument. It is essential to read the instructions wherever thesymbol appears in the manual.
# DANGER : is reserved for conditions and actions that arelikely to cause serious or fatal injury.
# WARNING : is reserved for conditions and actions that cancause serious or fatal injury.
# CAUTION : is reserved for conditions and actions that cancause injury or instrument damage.
̶1̶# DANGER● Never make measurements on circuits in which earth
potentials higher than the following values exist.
* 300 V or higher in CAT II, 150 V or higher in CAT III and
100 V or higher in CAT IV environment.
● Keep your hand and fingers behind the protective finger guard
during a measurement.
● Do 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.
● Never attempt to use the instrument if its surface or your handis wet.
● Be careful not to short-circuit the power line with the metal
part of the test lead during a measurement. It may cause
personal injury.
● Do not exceed the maximum allowable input of any measuring range.
● Ensure that the test leads are firmly connected to the
instrument, and then press the TEST button.
● Never open the battery compartment cover during ameasurement.
● T he instrument should be used only in its intended
applications or conditions. Otherwise, safety functions
equipped with the instrument do not work, and instrument
damage or serious personal injury may be caused.
● Keep your fingers and hands behind the protective fingerguard
during measurement.
# WARNING● Never attempt to make any measurements if any abnormal
conditions, such as a broken cover or exposed metal parts arepresent on the instrument and clamp sensor.
● 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 in case of suspectedfaulty operation.
● Do not try to replace batteries if the surface of the instrument is wet.
● Connect the test leads firmly into each terminal.
● Set the range selector switch to OFF position when opening
the battery compartment cover for battery replacement.
● Stop using the test lead if the outer jacket is damaged and theinner metal or color jacket is exposed.
̶2̶

# CAUTION● Always make sure to set the range selector switch to theappropriate position before making a measurement.
● Power off the instrument after use. Remove 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, hightemperature, humidity or dew.
● Use a damp cloth with neutral detergent or water for cleaning
the instrument. Do not use abrasives or solvents.
● If the instrument is wet, make sure to let it dry before putting it
into storage.

Symbols
CAT IIElectrical circuits of equipment connected to an
AC electrical outlet by a power cord.

CAT III

Primary electrical circuits of the equipment
connected directly to the distribution panel, andfeeders from the distribution panel to outlets.

CAT IVThe circuit from the service drop to the service
entrance, and to the power meter and primary
over-current protection device (distribution panel).

Double or reinforced insulation

User must refer to the explanations in the
instruction manual.



Earth
This instrument satisfies the marking requirement
defined in the WEEE Directive (2002/96/EC).
This symbol indicates separate collection forelectrical and electronic equipment.

̶3̶

Measurement Category
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 : The circuit from the service drop to the service entrance,
and to the power meter and primary over- current
protection device (distribution panel).

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

̶4̶

2．Features
This instrument is an earth resistance tester for testing power
distribution lines, in-house wiring system, electrical appliances etc. It
also has an earth voltage range to measure earth voltage.
● Designed to meet the following safety standards.
IEC 61010-1, IEC 61010-2-030 CAT II 300 V, CAT III 150 V,
CAT IV 100 V, Pollution degree 3
IEC 61010-031,
IEC 61557-1, -5● Dust and water-proof construction in conformity with IEC 60529 (IP67)
This instrument is water-proof, so it is washable.
● Backlight to facilitate working at dimly illuminated location or atnighttime work. The backlight automatically turns off if the range
selector switch is not moved or a button is not pressed for two minutes.
● The instrument automatically powers off if the range selector
switch is not moved or a button is not pressed for ten minutes.
※Au to - p owe r- of f fe at u re d o e s n' t a ctivate d u rin g d ata
communication via Bluetooth or continuous measurement.
● Shoulder strap for both-hands operation● Earth voltage measurement- AC/ DC auto detection- Warning LED for hazardous high earth voltage● Earth resistance measurement- If the auxiliary earth resistance of auxiliary earth spikes is toohigh to make a precision measurement, the display shows
warning and indicates which terminal, H(C) or S(P), has higher
values with a warning LED.
- Simplified measurement probe has a structure that both thealligator clip and the test bar are available.
- Comparator function to give warning when a measured value
exceeds the pre-set reference value. For further detail, see 8-1.
Comparator function in this manual. This function can be disabled.
● Equipped with Bluetooth communication function (KEW4105DLBT
only)
Remote monitoring and data save on your tablet device arepossible by pairing KEW 4105DLBT and your tablet.
※ KEW 4105DLBT has Bluetooth function and that is the only
difference from KEW 4105DL.
There're no differences of measurement functions between these
two models.
̶5̶

3．Specifications● Measuring range and accuracy (23ºC±5ºC, RH 75% or less)
Earth voltage measurement
Measuring range
0 to 300 V AC
(45 - 65Hz)±0 to ±300 V DC

Display range
0.0 to 314.9 V
0.0 to ±314.9 V

Accuracy±1%rdg±4dgt

Measuring method: Average sensing, True RMS value display* AC/ DC auto-detection for an input of 2 V or higher. The LCD
shows AC or DC mark according to the input polarity.
Earth resistance measurement
Range

Measuring
range

20Ω
Range
200Ω
Range
2000Ω
Range

0.00 to 2000Ω

Display range

Accuracy*1

0.00 to 20.99Ω

±1.5%rdg±0.08Ω*2

0.0 to 209.9Ω
0 to 2099Ω

±1.5%rdg±4dgt

Measuring method: Constant current inverter/ 825 Hz
Approx. 3 mA (20Ω Range)
Approx.1.7 mA (200Ω Range)*3
Approx. 0.7 mA (2000Ω Range)*3
For precision measurement, auxiliary earth resistance should be
100Ω±5% or less.
*2
At precision measurement or when using optional test leads
M-7241A, add ±0.10 Ω to the specified accuracy.
*3
Current is reduced as follows if auxiliary earth resistance is high.
Approx. 0.7 mA: 200Ω Range, if aux. earth resistance is 25kΩ orhigher.
Approx. 0.3 mA: 2000Ω Range, if aux. earth resistance is 50 kΩ
or higher.

*1

̶6̶

● Applicablestandards● IEC 61010-1
CAT II 300 V CAT III 150 V CAT IV 100 V
Pollution degree 3●IEC 61010-2-030●IEC 61010-031●IEC 61557-1, -5●IEC 60529 IP67
●IEC 61326-1, -2-2
●EN 50581
MODEL7127B…CAT III 300 V CAT IV 150V
* When test leads are connected to and usedwith the instrument, the lower category
either of them belongs to is applied.
Altitude 2000m or less, in-door/ out-door use
Liquid crystal display with backlight-10ºC to 50ºC, 80% or less (no condensation)● Location for use● Display● Operating temp.
& humidity● Storage temp.
-20ºC to 60ºC, 75% or less (no condensation)& humidity● External
Complies with Bluetooth Ver5.0.
communication
feature(KEW 4105DLBT only)● Withstand voltage 2210 V AC (50/60Hz) / 5 sec
Between electrical circuit and enclosure● Insulation
50 MΩ or more/ 1000 V DC
resistance
Between electrical circuit and enclosure● Auto power off
Turns off the instrument automatically iffunction
there is no function change, range change orbutton press for about 10 min.
● Backlight
Automatically turns off if there is no activity
for about 2 min.
*Auto-off is disabled during a measurement.
● Dimensions
121(L)×188(W)×59(H) mm * including case lid● Weight
Approx. 690g * including batteries and case lid● Power source
Six size AA alkaline batteries (LR6)̶7̶

● Operating uncertainty
Operating uncertainty (B) is an uncertainty obtained under the
rated operating conditions, and calculated with the intrinsic
uncertainty (A), which is an error of the instrument used, and theerror (En) due to variations.
According to IEC61557, the maximum operating uncertainty
should be within ± 30%.
● Operating uncertainty in earth resistance measurements(IEC61557-5)* Formula: B = ±(｜A｜+ 1.15 x √E 22 + E 32 + E 42 + E 52 )A

Intrinsic uncertainty

E2

Variation due to changing the Battery voltage (till thebattery indicator becomes empty)

E3

Variation due to changing the temperature(-10ºC to 50ºC)

E4

Variation due to series interference voltage
16·2/3 Hz, 50 Hz, 60 Hz: 25 V
DC: 10 V
400 Hz: 5 V

E5Variation due to resistance of the auxiliary earth electrode20Ω range: 0 ‒ 10 kΩ
200Ω range: 0 ‒ 50 kΩ
2000Ω range: 0 ‒ 100 kΩ

* The measuring range to keep operating uncertainty of ± 30%:
20Ω range: 5.00 Ω ‒ 20.00 Ω
200Ω range: 20.0 Ω ‒ 200.0 Ω
2000Ω range : 200 Ω ‒ 2000 Ω● Possible number of measurements where battery voltage is within
the effective range (measurement of 5 sec., pause of 25 sec.)
Function

Test resistor

Possible number ofmeasurements

Earth measurement

10 Ω

Approx. 10000 times

̶8̶

4．Name of parts(1) Front panel

①

②

③

④

⑥ ⑤

Name

Fig. 4-1

Description① LCD

LCD with backlight② Test button

Starts/ stops a measurement.

③ Backlight button

Turns on/ off the backlight.

④ Range selector switch

Selects a range for earth resistance orearth voltage measurement.

⑤

G r e e n L E D li g h t s u p i n e a r t h
LED for aux. earth
measurements while the auxiliary earth
resistanceresistance is within the allowable range.

⑥

Red LED lights up in earth voltage
Earth voltage warning
measure-ments if the earth voltage isLEDover the allowable range.

̶9̶

(2) Terminal part

①

②

③

Fig. 4-2

Terminal

Designated function

E

For an earth electrode

②

S(P)

For an aux. earth (potential) electrode

③

H(C)

For an aux. earth (current) electrode①(3) LCD

Fig. 4-3● Symbols common to all functions
Battery level indicator
Segments for numerical display
Indicates Over-range status ‒ the measured
value is exceeding the display range.
Resistance: >20.99 (20Ω range)>209.9 (200Ω range)>2099 (2000Ω range)
Voltage: >314.9V( <-314.9V is displayed
for negative DC input)
̶ 10 ̶

● Symbols for earth measurement
Measurement unit
Warning - Aux. earth resistance is too high.
(See P. 18.)
Data hold is active.
Comparator function is active.
While the comparator function is active, thesesigns indicate that the present input is morethan the pre-set threshold values.
>10 Ω (20Ω range)>100Ω (200Ω range)>500Ω(2000Ω range)#

While the comparator function is active, thissign indicates that the present input is morethan the pre-set threshold value.

● Symbols for voltage/ earth voltage measurement
Alternating current, direct current
Unit for voltage measurement
Indicates that the negative voltage is measured.

̶ 11 ̶

5．Accessories(1) Test leads for precision measurement MODEL7266(Red: 20m, Yellow: 10m, Green: 5m)

Fig. 5-1(2) Test leads for simplified measurement MODEL7127B
2pcs (red & black)Protective
finger guard*4

2pcs (black)Protective
finger guard*4*4Fig. 5-2

Protective finger guard is a part providing protection against electricalshock and ensuring the minimum required air and creepage distances.

(3) Auxiliary earth spike MODEL8041

Fig. 5-3(4) Cable reel (supplied depending on the purchased model)

Yellow cable (10m)

Red cable (20m)

Fig. 5-4

Cable reel + Red cable (20m) MODEL7267
Cable reel + Yellow cable (10m) MODEL7268
̶ 12 ̶

(5) Shoulder strap MODEL9121(6) Six AA alkaline batteries (LR6)(7) Instruction manual(8) Hard case MODEL9191 (supplied depending on the purchased model)
Each item can be stored as shown below.
Test leads for
simpliﬁed measurement

Test leads for
precision measurement

Auxiliary earth spikes
Main unit

Fig. 5-5(9) Soft case MODEL9190 (supplied depending on the purchased model)
Each item can be stored as shown below.
Test leads for
simpliﬁed measurement
and forprecision measurement (green)

Main unit

Fig. 5-6
Cable reels

Auxiliary earth spikes* No cable reel is included for the tester -H model ; it comes withhard case MODEL 9191 instead of soft case.
How to house the tester in hard case:Set the top cover of the tester to the rear side, and install the testerin the specified place in the hard case and gently press the front
side of the tester.
Press and secure.
Two hooks
on hard case̶ 13 ̶

How to take out the tester from hard case:
Perform housing procedure in reverse order.
Pull up the tester in sloping direction and then take out the tester.
● Optional accessories(1) Adapter for measurement terminal MODEL8259
Oﬀering easy connection of acable with spade connector

Red, yellow, green

Fig. 5-7
Fig. 5-8# DANGER
Do not connect the adapter of precision test leads to mains
power or a circuit in which electrical potentials exceeding 33 V
rms, 46 V (peak value) or 70 V DC exist; otherwise, electricalshock may be caused by the exposed electrode.
# CAUTION
Resistance of test leads to be connected to E terminal affects
measured results. The specified accuracy may not be guaranteed
if test leads other than the ones supplied with this instrument areused.
(2) Test leads for precision measurement MODEL7241A(Red, Yellow, Green: 1.5m)

Fig. 5-9

̶ 14 ̶

6．Getting startedBattery voltage check(1) Please refer to 12. Battery replacement in this manual and insert
batteries in this instrument.
(2) Turn and set the range selector switch to any position other thanOFF to power on the instrument.
(3) Battery level indicator appears at the upper left on the LCD.
Battery voltage is extremely low ifmark is displayed.
Replace batteries with reference to 12. Battery replacement tocarry out further measurements.
If empty
mark is displayed, battery voltage is below thelower limit of the operating voltage. In such a condition, accuracyof the measured result isn t guaranteed. Replace the batteries assoon as this mark appears.
Use of A A alkaline battery is recommended. Use of otherbatteries may cause improper indication of battery level.

̶ 15 ̶

7．Earth resistance measurement
With the earth resistance measurement function of this instrument,
earth resistance of power distribution lines, in-house wiring systemand electrical appliances can be measured.
# DANGER● Be extremely careful when measuring earth resistance; highvoltage, 50 V max is generated across H(C) ‒ E terminals.
● When measuring earth voltage, do not apply 300 V or higher
voltage between S(P) ‒ E and between H(C) ‒ E terminals.
● When measuring earth resistance, do not apply voltage, morethan 25 V, between measuring terminals.
7-1. Measurement principle
This instrument makes earth resistance measurement with fall-ofpotential method, which is a method to obtain earth resistance value
Rx by applying AC constant current I between the measurement
object E (earth electrode) and H(C) (current electrode), and finding out
the potential difference V between E and S(P) (potential electrode).
Constant current generator
VoltmeterV
V = Rx × I～

I

S(P)(Potential) H(C)(Current)

Rx = V / I

Fig. 7-1

E(Earth)

7-2. Precision measurement (with test leads for precision measurement)(1) Connection
Stick the auxiliary earth spikes S(P) and H(C) into the grounddeeply. They should be aligned at an interval of 5 - 10 m fromthe earthed equipment under test. Connect the green wire to theearthed equipment under test, the yellow wire to the auxiliary
earth spike S(P) and the red wire to auxiliary earth spike H(C)from terminals E, S(P) and H(C) of the instrument in order. See
Fig. 7-2 and 7-3.
̶ 16 ̶

Fig. 7-2
Green

Yellow

Green

Red

YellowRed

Earthed electrode
under test

Auxiliary
earth spikes

Fig. 7-3

Insert the plug of test leads firmly into each terminal. If they are notinserted firmly, the loose connection may cause inaccurate readings.
Note:
Make sure to stick the auxiliary earth spikes in the moist part of thesoil. Give enough water where the spikes have to be stuck into thedry, stony or sandy part of the earth so that it may become moist.
In case of concrete, lay the auxiliary earth spike down and water it,or put a wet cloth etc. on the spike when making measurement.
Confirm that the LED for aux. earth resistance lights up before
pressing the TEST button. For further detail, please refer toClause7.2, (4) Auxiliary earth resistance. Aux. earth electrodes
cannot be used on the ground such as asphalt where water will notpermeate.
(2) Earth voltage check● Select the Earth voltage function and check the voltage value
displayed on the LCD. The displayed earth voltage is thevoltage between S(P) and E terminals.
Display example

Fig.7-4

̶ 17 ̶

Confirm that the displayed voltage value is 25V or less. When the display
reads more than 25V, the warning LED as shown below lights up.
(The warning LED lights up at; more than 10V for DC earth voltage
and more than 5 V for earth voltage of 400 Hz.)Red LED lights up.

Fig. 7-5

Excessive errors in earth resistance measurement may be causedin the condition that warning LED for high earth voltage is lighting
up. To avoid this, make measurement after reducing the voltage byturning off the power supply of the equipment which is connectedto the earthed electrode under test etc. Earth voltage warning LED
works on earth resistance function.
# DANGER● Do not connect the precision measurement test leads to a circuit
in which electrical potentials exceeding 33 V rms, 46 V peak or
70 V DC exist, in addition, not use them for voltage measurement.
(3) Measurement
Select a desired range and press the TEST button to startmeasurement.
TEST button LED blinks to indicate the instrument is performing
measure-ment. The displayed value is the earth resistance ofthe earthed electrode under test. Press the TEST button again
to stop measurement. If the measured result exceeds the display
range, set the rotary selector switch to a higher range.
Display example

Fig. 7-6

When the measured result exceeds the display range (over-range),
the LCD shows:>20.99Ω (20Ω range)>209.9Ω(200Ω range)>2099Ω (2000Ω range).
̶ 18 ̶

(4) Auxiliary earth resistanceIf the auxiliary earth resistance is within the allowable range
and doesn t affect measurement, the green LED shown below
lights up. The table below shows the upper limit of auxiliary earth
resistance.

Green LED lights up.

Fig. 7-7

Upper limit of auxiliary earth resistance
Measurement range

Aux. earth resistance

20Ω

10 kΩ

200Ω

50 kΩ

2000Ω

100 kΩ

If the auxiliary resistance of auxiliary spike H(C) or S(P) is too high tomake measurement, the display reads RH̲H or RS̲H . Recheck theconnection of test leads and the earth resistance of auxiliary earth spike.
When earth resistance at H(C)(aux. earth (current) electrode)is too high:Fig. 7-8

When earth resistance at S(P)(aux. earth (potential) electrode)is too high:Fig. 7-9

Indications of aux. earth resistance warning are switchable: RH̲H-> RC̲H, RS̲H -> PR̲H. For further detail, please refer to 9.
Switching indications of aux. earth resistance warning.

̶ 19 ̶

# CAUTION● If measurement is made with the test leads twisted or in touchwith each other, the reading of the instrument may be affectedby induction. For accurate measurement, test leads should bearranged so as not to be contacted with each other.
● If earth resistance of auxiliary earth spikes is too large, it may
result in inaccurate measurement. Make sure to stick theauxiliary earth spikes H(C) and S(P) into the moist part of theearth carefully, and ensure sufficient connections between therespective connections.
7-3. Sim plifie d m easu rem e nt (with test lea d s fo r
simplified measurement)
Use this method when the auxiliary earth spike cannot be stuck. In
this method, an existing earth electrode with a low earth resistance,such as a metal water pipe, a common earth of a commercial power
supply and an earth terminal of a building, can be used with twopole method.
(1) Connect the test leads as Fig. 7-10 shows.
M O D E L712 7 B (re d ) to H (C) a n d S ( P) terminals , a n d
MODEL7127B (green) to EARTH (E) terminal.

Green

Yellow

Red

Fig. 7-10

Tip adapters for the test leads for simplified measurement can bechanged depending on the applications.

̶ 20 ̶

[How to attach]Firmly insert and connect the adapter you want to use to the end of
the cord (with banana plugs at both ends).
Alligator clip

Banana plugs, both ends

Flat test bar

Fig. 7-11

Insert the plug of test leads firmly into each terminal. If they are notinserted firmly, the loose connection may cause inaccurate readings.
# DANGER● To avoid getting electrical shocks, ensure that test leads are
disconnected from the instrument when replacing the metal tip
or adapter for test leads.
(2) Wiring
Make connection as shown in the following figure.
Indicated
value

Red

Secondaryside

Primary
side

Supply TransformerGreenBe sure to cheak
Earthedearthed side ofelectrodea commercial
under test
power supply
Where earth for mains supply is used

Fig. 7-12# DANGER● Use a voltage detector to check a common earth of commercial
power supply.
● Do not use this instrument to check a common earth ofcommercial power supply. A danger will be caused because thevoltage may not be displayed even in case of a live conductor,
when the connection of the earth electrode to be measured
has come off, or when the connection of the test leads of the
instrument is not correct etc.
̶ 21 ̶

(3) Earth voltage check● Select the Earth voltage function and check the voltage value
displayed on the LCD. The displayed earth voltage is thevoltage between S(P) and E terminals.
Confirm that the displayed voltage value is 25 V or less. When thedisplay reads more than 25 V, the warning LED as shown below
lights up. (The warning LED lights up at; more than 10 V for DC
earth voltage and more than 5 V for earth voltage of 400 Hz.)

Display example

Fig.7-13

Fig. 7-14

Red LED lights up.

Excessive errors in earth resistance measurement may be causedin the condition that warning LED for high earth voltage is lighting
up. To avoid this, make measurement after reducing the voltage byturning off the power supply of the equipment which is connected tothe earth electrode under test etc. Earth voltage warning LED works
on earth resistance function.
(4) Measurement
Select a desired range, and press the TEST button to startmeasurement. LED lights up to indicate the instrument isperforming a measurement. The displayed value is the earth
resistance of the earthed electrode under test. Press the TEST
button again to stop measurement. If the measured result
exceeds the display range, set the rotary selector switch to ahigher range.

Display example

Fig. 7-15

̶ 22 ̶

When the measured result exceeds the display range (over-range),
the LCD shows:>20.99Ω (20Ω range)>209.9Ω(200Ω range)>2099Ω (2000Ω range).
(5) Simplified measurement value
Two-pole method is used for simplified measurement. In thismethod, earth resistance value re of earth electrode connected
to terminal H(C) ‒ see Fig. 7-12 - is added to true earth
resistance value Rx and shown as an indicated value Re.
Re (indicated value) = Rx + reIf the re is known beforehand, true earth resistance value Rx is
calculated as follows.
Rx (true resistance) = Re – re8．Comparator function
8-1. Comparator function
When the measured value in earth measurement exceeds a certain
reference value, the LCD shows # mark and corresponding warning
indication with blinking backlight. (See Fig. 8-1.)
Reference values for each range
Range
Reference value20Ω
10.00 Ω200Ω100.0 Ω2000Ω500 Ω
● Hysteresis of reference value
The warning will not stop or go off until the measured value drops
99% or less of each reference value.
Measured values that cancel the warning;20Ω range: 9.90 Ω or less200Ω range: 99.0 Ω or less2000Ω range: 495 Ω or less
̶ 23 ̶Display example (200Ω range)
Measured value is lower than
the reference value

BlinksIn case the measured value
exceeds the reference value

Fig. 8-1

8-2. How to enable/ disable comparator function* The comparator function has been disabled by default.
1. Set the range selector switch to OFF position.
2. Power on the instrument while holding down the backlight button.
3. All segments in the LCD light up, and then
COMP
mark
blinks twice to indicate the comparator function is enabled.
To disable the function, perform above steps 1. and 2. while thefunction is enabled. The COMP mark blinks twice and the function
is disabled.
The COMP mark is always displayed on resistance ranges while thecomparator function is enabled. (See Fig. 8-2.)
COMP mark lights up.

Fig. 8-2

̶ 24 ̶

9. Switching indications of aux. earth resistance warning
Warning indications for aux. earth resistance can be switchedbetween (1) and (2) as shown in the table below; default setting is (1).
Conditions

(1)

(2)

Resistance at H(C)terminal is high.
Resistance at S(P)terminal is high.
● How to switch the indications:(1) Turn the range selector switch from OFF to EARTH VOLTAGE
while pressing down the TEST and backlight button. Thenthe currently selected indication will be displayed for one
sec. When the indication switches from (1) to (2), the LCD
shows RC̲H and RP̲H one second each.
(2) Repeating above operation switches the indications in turn, (1)-> (2) ‒>(1)….

10. Backlight
Press the backlight button to turn on the backlight. Press the button
again to turn off the backlight. The backlight automatically turns off
if there is no activity for about 2 min. (*Auto-off is disabled during ameasurement.)

̶ 25 ̶

11. Bluetooth communication (KEW 4105DLBT only)
11-1 Bluetooth communication
KEW 4105DLBT can communicate with Android/iOS tablet devices
via Bluetooth. You can check the measured results remotely on yourdevice by installing the special application KEW Smart*(asterisk)
in your device.
This feature is available only on KEW 4105DLBT: unavailable on
KEW 4105DL.
First, download the special application "KEW Smart*" via theinternet.
Some functions are available only while connected to theinternet. For further detail, please refer to "11-2 Features of KEW
Smart*(asterisk)".
# WARNING
Radio waves at Bluetooth communication may affect the operationsof medical electronic devices. Special care should be taken whenusing Bluetooth connection in the areas where such devices arepresent.
● Use of the tester or tablet devices near wireless LAN devices(IEEE802.11.b/g) may cause radio interferences or lowering ofcommunication speed, and as a result significant time lag occurs
in the display update rate between the tester and tablet device.
In this case, keep the tester and the tablet device away from thewireless LAN devices, or turn off the wireless LAN devices, orshorten the distance between the tester and the tablet device.
● It may be difficult to establish communication connection if either
the tester or tablet device is in a metal box. In such a case,change the measurement location or remove metal obstacles
between the tester and the tablet device.
● If data or information leak occur during Bluetooth communication,
we assume no responsibility for any released content.
̶ 26 ̶

● Some tablet devices, even if the application runs properly, may failto establish communication with the tester. Please use anothertablet device and try to communicate with. If you still cannot
confirm the connection, there may be some problem with thetester itself.
Please contact your local KYORITSU distributor.
● The Bluetooth word mark and logos are owned by Bluetooth SIG,
Inc. and we, KYORITSU, are licensed by them for use.
● Android, Google Play Store, and Google Maps are the trademarkor registered trademark of Google Inc.
● iOS is the trademark or registered trademark of Cisco.
● Apple Store is the service mark of Apple Inc.
● In this manual, the "TM" and " ® " marks are omitted.
11-2 Features of KEW Smart*(asterisk)
The special application "KEW Smart *" is available on downloadsite for free. (Internet access is required.) Please note that
communication charge is incurred separately for downloading
applications and using special features of them. For your information,"KEW Smart *" is provided on-line only.
Features of KEW Smart*:● Remote monitoring/ checking● Data save/ recall function● Map display (App for Android only)
Measured locations can be checked on Google Maps if the
saved data includes GPS location info.
● Comment editing
Measured result can be saved with comments.
The latest information about "KEW Smart*" can be checked with thesite on Google Play Store or App Store.

̶ 27 ̶

12. Battery replacement
Replace the batteries as soon as themark appears.

# DANGER● Do not open the battery compartment cover if the instrument is wet.
● Never attempt to replace batteries during a measurement.
In order to avoid getting electrical shock, ensure that the
instrument is powered off and test leads are disconnected fromthe instrument before replacing batteries.
● The battery compartment cover must be closed and screwed
before starting a measurement. Otherwise, electrical shock
hazard may be caused.
# CAUTION● Do not mix new and old batteries or mix different types ofbatteries.
● Install batteries in correct polarity as marked inside. Do not open
the battery compartment cover if the instrument is wet.
● In order to preserve water-proof feature, do not remove thepacking from the battery compartment cover and keep the
packing clean. Wipe off any tiny dust particles from the packing
surface.

Packing

Fig. 11-1(1) Power off the instrument, and then disconnect the test leads.
(2) Loosen two screws which are fixing the battery compartment
cover, and remove the cover.
(3) Replace all six batteries with new ones at the same time. Be surethat the battery polarity is correct.
Use of six size AA alkaline batteries (LR6) is recommended.
(4) Install the battery compartment cover, and tighten two screws forthe cover.
̶ 28 ̶

# CAUTION
Remove all batteries if the instrument is to be stored and will not be
in use for a long period.
In this case, when attaching the battery compartment cover, keep
the right screw of the cover slightly loose.

Right screw

Fig. 11-2

This instrument has water-proof feature and has high sealing
property, therefore, air pressure adjustment is necessary.
Air pressure between inside and outside of the instrument can bebalanced by loosening the right screw of the battery compartment
cover. Always tighten the screw completely before using the
instrument.

13. CleaningThis instrument is designed to meet IP67 (IEC 60529) dust andwater-proof construction.
IP67
This indicates the degree of protection provided by the enclosure of thedevice against entry of solid foreign objects, and the ingress of water.
IP6x: Dust-proof type (Dust shall not penetrate the enclosure.)
IPx7: Watertight (Quantities of water that may harm the enclosure
when it is temporarily immersed in water shall not penetrate
the enclosure.)
Use a damp cloth with neutral detergent or water for cleaning the
instrument. Do not use abrasives or solvents. Read and observe thefollowing cautions when washing the instrument.
̶ 29 ̶

# CAUTION● The watertight feature may be degraded after prolonged use.
This feature works on fresh water and tap water only and isguaranteed as long as the following conditions are met.
- Temperature of fresh water or tap water is 15 ‒ 35℃.
- Ambient temperature is 15 ‒ 35℃.
- Difference in temperatures of water and instrument enclosure is
within 5℃● Replace the waterproof packing if it is degraded.
● Check the packing for deformation, cracks when washing the
instrument and firmly secure the battery compartment cover when
washing the instrument.

14. Notes on housing case
Case lid can be fit under the housing case while making
measurement.
①

②

③

④

Fig. 13-1

̶ 30 ̶

15. How to fit strap belt
The instrument is equipped with a strap belt to suspend fromthe neck to allow both hands to be used freely for easy and safe
operation.

Fig. 14-1

16. Cable reels
16-1. Operating instruction
Connection②①

Fig. 15-1
Connect the cable to the instrument.

Fig. 15-2
Pull out the cable from the cable reel.

③

Earthed electrode
under test
Make the connection as theﬁgure shows.

Fig. 15-3

̶ 31 ̶

Auxiliary
earth spikes

Storage
First, house the alligator clip onto the cable reel as follows. Thenhold the grip of the cable reel with your left hand and slack thecable downward.
Rotate the handle with your right hand for rewinding.
Alligator
clip

Fig. 15-4

Fig. 15-5

Fig. 15-6
Plug cap can be housed in
the center of the cable reel.

16-2. Cable replacement
How to remove the cable
Hook
To replace the cable with a new one, ﬁrst, pull out
the cable fully. Then take the bottom cover away,
and remove the cable from the cable reel.
No need to remove the alligator clip.

Fig. 15-7
How to attach a new cable
For attaching a new cable, reverse the procedure above.

Insert a cable throughthe bottom.

Fig. 15-8

House the alligator
clip and cable.

Attach the bottom cover
and wind the cable.

Fig. 15-9

Fig. 15-10

This cable reel is washable. You can remove dirt and mud easily.
̶ 32 ̶DISTRIBUTOR

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

1-23

92-2259C