DISTRIBUTORINSTRUCTION MANUAL

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

MULTI-FUNCTION TESTERKEW 6516 / 6516BT
11-2192-2385C

CONTENTS
1. Safe testing................................................................................................................. 1
2. Instrument layout ........................................................................................................ 3
3. Accessories ................................................................................................................ 5
4. Features ..................................................................................................................... 7
5. Specification ............................................................................................................... 9
5.1 Measurement specification ................................................................................... 9
5.2 General specification .......................................................................................... 14
5.3 Applied standards ............................................................................................... 15
5.4 Operating uncertainty ......................................................................................... 16
5.5 Symbols and marks displayed on the LCD......................................................... 18
6. Setup mode .............................................................................................................. 19
7. Getting started .......................................................................................................... 20
7.1 Attaching metal tip/ adapter for test leads .......................................................... 20
7.2 Battery voltage check ......................................................................................... 21
7.3 Clock adjustment ................................................................................................ 21
7.4 Help function....................................................................................................... 22
8. Continuity (resistance) tests ..................................................................................... 23
8.1 Test procedure .................................................................................................... 23
8.2 2Ω Buzzer () function.................................................................................. 25

8.3 Switching test currents ....................................................................................... 25
8.4 Pat function......................................................................................................... 25
9. Insulation tests.......................................................................................................... 27
9.1 Measurement method......................................................................................... 28
9.2 Continuous measurement (Insulation resistance measurement) ....................... 30
9.3 Voltage characteristics of measurement terminals ............................................. 30
9.4 DAR/ PI measurement, 1-min value display ....................................................... 31
9.5 Pat function......................................................................................................... 31
9.6 SPD(Varistor) test ............................................................................................... 32
10. LOOP/ PSC/PFC ..................................................................................................... 33
10.1 Principles of measurement ............................................................................... 33
10.2 Measurement method for LOOP high current .................................................. 38
10.3 Measurement method for LOOP ATT (Anti trip technology) ............................. 42
10.4 Loop limit value................................................................................................. 46

11. RCD tests ................................................................................................................ 48
11.1 Principles of RCD measurement ..................................................................... 48
11.2 Principles of Uc measurement ......................................................................... 50
11.3 Measurement method for RCD ........................................................................ 50
11.4 Auto test ........................................................................................................... 53
11.5 VAR (variable current value) function .............................................................. 53
11.6 EV RCD ........................................................................................................... 54
12. Earth tests ............................................................................................................... 54
12.1 Principles of earth measurement ..................................................................... 54
12.2 Earth resistance measurement........................................................................ 54
12.3 Measurement method for earth ....................................................................... 55
13. Phase rotation tests ................................................................................................. 57
14. Volts ......................................................................................................................... 58
15. Touch pad ................................................................................................................ 58
16. Memory function ...................................................................................................... 59
16.1 How to save the data ....................................................................................... 59
16.2 Recall the saved data ...................................................................................... 60
16.3 Delete the saved data...................................................................................... 61
17. Transfer the stored data to PC ................................................................................ 62
18. Bluetooth communication (KEW 6516BT only) ....................................................... 63
18.1 Bluetooth communication ................................................................................ 63
18.2 KEW Smart * ................................................................................................... 64
19. Auto-power-off ......................................................................................................... 64
20. Battery and fuse replacement.................................................................................. 65
20.1 Battery replacement ........................................................................................ 66
20.2 Fuse replacement ............................................................................................ 65
21. Servicing .................................................................................................................. 66
22. Case and strap assembly ........................................................................................ 67

The KEW 6516/6516BT incorporates Anti Trip Technology (ATT) which electronicallybypasses RCDs when performing loop impedance tests. This saves time and money by
not having to take the RCD out of the circuit during testing and is a safer procedure tofollow. With the ATT function enabled, a test of 15mA or less is applied between line &earth. It enables loop impedance measurements without tripping RCDs rated at 30mA
and above.
ATT supports measurements using three wires: Line, Earth, and Neutral and also two
wires: Line and Earth.
Please read this instruction manual carefully before using this instrument.

1. Safe testingThis instrument has been designed, manufactured and tested according to IEC 61010:
Safety requirements for electrical equipment for measurement, 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 in safe condition. Therefore, read through these operating
instructions before starting to use the instrument.
# DANGER● Read through and understand instructions contained in this manual before starting
to use the instrument.
● Keep the manual at hand to enable quick reference whenever necessary.
● 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 relatedparts in the manual for safe operation of the instrument. It is essential to read the
instructions wherever the symbol # appears in the manual.
# DANGER : is reserved for conditions and actions that are likely to cause serious or
fatal injury.
# WARNING : is reserved for conditions and actions that can cause serious or fatal
injury.
# CAUTION : is reserved for conditions and actions that can cause injury or
instrument damage.
# DANGER● Do not apply voltages above 600V, including voltage to earth, across the terminalsof this instrument.
● KEW 6516/ 6516BT are rated to CAT IV 300V/ CAT III 600V. Do not makemeasurements under the circumstances exceeding the designed measurement
categories.
● Do not attempt to make measurements in the presence of flammable 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 hand is wet.
● Be careful not to short-circuit a power line with the metal part of the test lead during
a measurement. It may cause personal injury.
● Never open the battery compartment cover during a measurement.
● The instrument should be used only in its intended applications or conditions;otherwise, safety functions equipped with the instrument don't work, and instrument
damage or serious personal injury may be caused.
● Verify proper operation on a known source before use or take actions as a result of
the indication of the instrument.

1

# WARNING● Do not use the instrument or test leads if any abnormal conditions, such as broken
cover or exposed metal parts are noted.
● First, firmly connect the test leads to the instrument, and then press the test switch.
● Never install substitute parts or make any modifications to the instrument. Send the
instrument to your local KYORITSU distributor for repair or recalibration.
● Do not try to replace batteries if the surface of the instrument is wet.
● Connect each test lead firmly into the corresponding terminals.
● Stop using the test lead if the outer jacket is damaged and the inner metal or color
jacket is exposed.
● Before opening the battery compartment cover for battery or fuse replacement,
ensure that no test leads are connected to the instrument and the instrument is off.
● Never turn the rotary switch while the test leads are connected to the equipment
under test.
# CAUTION● Always make sure to set the rotary switch to the appropriate position before making
a measurement.
● Power off the instrument after use. Remove batteries if the instrument is to be
stored and won't be used for a long period.
● Do not expose the instrument to direct sunlight, high temperature, humidity or dew.
● Use a slightly damp cloth with neutral detergent or water for cleaning. Do not use
abrasives or solvents.
● This instrument isn't water-proof. Do not let the instrument get wet. Otherwise, it
may cause malfunction.
● If the instrument is wet, make sure to let it dry before putting it into storage.
● Keep your hand and fingers behind the protective finger guard during ameasurement.

22. Instrument layout
(5)

(6)

(1)

(2)
(3)

(7)

(4)
Fig.2-1

Item(8)

Description(1) Test switch

Starts measurements. (Press and rotate for lock downfeature.)(2) Touch pad

Checks the electrical potential at the PE terminal(3) Power switch

A long press turns on/ off the instrument.
(A short press works as an ESC switch to return to theprevious screen.)(4) Function switch

Function setting (F1 ~ F4)(5) Display (LCD)

Color LCD

(6) Rotary switch

Selects measurement functions.

(7) MEM switch

Saves measured value.
(Press 1 sec. to recall the saved data.)(8) ENTER switch

Confirms changes or selections.
(A long press of 1 sec. shows "HELP" menu.)

3Input Terminal
(4)
(1)
(2)
(3)
Fig.2-2Function

Terminal

Terminals for :INSULATION,CONTINUITY
(1)
LOOP,
RCD,
VOLTS

L : Line
PE : Protective EarthN : Neutral (for LOOP, RCD)
L1 : Line1(2)

Terminal for
PHASE ROTATION

L2 : Line2
L3 : Line3
H(C) : Terminal for auxiliary earth spike (current)(3) Terminal for EARTH

E : Terminal for the earth under test
S(P) : Terminal for auxiliary earth spike (potential)(4) Optical adapter

Communication port for Model 8212USB

4

3. Accessories●Test leads(1) Mains Test Lead (Model 7218A)
Red (Line)
Green (Protective Earth)Blue (Neutral)

Fig.3-1

Fig. 3-1 shows Model 7218A with European SHUKO plug: plug shape varies dependingon the country or region. Any of the following test leads is selected and packed
according to destination.
●Model 7222A(AU) for Australian plug
●Model 7187A (UK) for British plug
●Model 7221A (SA) for South African plug(2) Remote Test Lead (Model 7281)*1 Protective Finger Guard

Insulation cap

Metal tip
Fig.3-2

Attach the supplied detachable
cap as necessary.
For CAT III 600V (w/ cap)
For CAT II 1000V (w/o cap)

(3) Distribution Board test lead (Model 7246)

Red (Line or L1)
Green (Protective Earth or L2)

Blue (Neutral or L3)*1 Protective Finger Guard

Fig.3-3* 1 Protective finger guard is a part providing protection against electrical shock andensuring the minimum required clearance and creepage distances.

5(4) Earth Tests Lead (Model 7228A) and Auxiliary Earth Spikes
Red H(C) 20m
Yellow S(P)10m
Green E 5m

Fig.3-5

Model 8041 Auxiliary Earth Spikes x 2

Fig.3-4・Other accessories(1) Test Lead Carry pouch Model 9084･･･x1(2) Carrying Bag Model 9142･･･x1(3) Instruction Manual･･･x1(4) Shoulder Strap (with buckle) Model 9151･･･x1(5) Shoulder Pad Model 9199･･･x1(6) Battery･･･x8(7) Spare Fuse F 0.5A 600V (Φ6.3 x 32mm)･･･ x1 (SIBA 7009463.0,5)*Stored in the battery compartment.
(8) Model 8212USB with PC Software KEW Report .
(Standard accessory for KEW 6516, optional for KEW 6516BT)

Fig.3-6
・Optional item
(1) Extension prod Model 8017A* Attached and used with Model 7281.

Fig.3-7

Long type and helpful to accessthe distant measurement spot6

4. Features
The KEW 6516/ KEW 6516BT Multi-Function tester has eight test functions in one
instrument.
1 Continuity test
2 Insulation resistance test
3 Loop impedance test (High current measurement, No trip (ATT) measurement)
4 Prospective short circuit current test (On Loop impedance function)
5 RCD test
6 Voltage test
7 Phase rotation test
8 Earth test
Continuity function has the following features:
Fuse Protection
Continuity Null
15mA test
Continuity 2Ω Buzzer

Continuity Function has a fuse protection function to preventa fuse blow at live working. With this function, a fuse rarely
blows while measuring continuity on live conductors.
Allows automatic subtraction of test lead resistance fromcontinuity measurements.
Not only 200mA but also 15mA is available.
Buzzer sounds at 2Ω or less at Continuity function.
(Switchable on or off)

Insulation function has the following features:Electric charges stored in capacitive circuits are discharged
Auto-discharge
automatically after testing by releasing the test switch.
Breakdown voltage measurement for surge protective device
SPD(VARISTOR) test
(varistor)
Loop impedance functions have the following features:
ATT test
LOOP 0.001Ω test

Enables loop impedance tests without tripping RCDs rated at
30mA or higher. (applicable to 3 or 2-wire measurements)
High resolution measurement, 0.001Ω, at a test current of
25A

7

RCD testing functions have the following features:
RCD Type B test
Capable of testing Type B RCDs of dc residual current.
VAR(variable test current) Test current is variable on RCD range.
Auto-test in the following sequence: ×1/2(0°)→×1/2(180°)
RCD AUTO TEST
→ ×1(0°)→×1(180°)→×5(0°) →×5(180°)
EV RCDEV charger RCD test
The following features are available on all testing functions.
Touch Pad
Memory Function
Bluetooth(KEW 6516BT only)

Gives an alert, when touching the Touch Pad, while the PE
terminal is connected to Line by mistake.
Save the measured data in the internal memory.
The data can be edited on a PC by using Communication
Adapter Model 8212USB and PC Software "KEW Report".
Remote monitoring and saving data on a Bluetooth tablet
device.

8

5. Specification
5.1 Measurement specification
VOLTS
Range
Display range

300.0/600V (Auto-ranging)
Voltage: 2.0 – 314.9V, 240 – 629V
Frequency: 40.0 – 70.0Hz (displayed at 2V or higher)

Measuring range(Guaranteed accuracy
range)

Voltage: 2 – 600V
Frequency: 45 – 65Hz

Accuracy

Voltage: ±2%rdg±4dgt
Frequency: ±0.5%rdg±2dgt* True-RMS detection. Add ±1%rdg to the declared accuracy for sine wave other thanCF<2.5. (850Vpeak or less)
PHASE ROTATION
Measuring range
Criteria of judgement

48 – 600V 45 - 65Hz
Correct sequence: Clockwise symbol and "1, 2, 3" aredisplayed.
Reversed sequence: Counter-clockwise symbol and "3, 2, 1"
are displayed.

EARTH
Precise measurement

Simplified measurement

Range

20.00/ 200.0/ 2000Ω (auto-ranging)

Display range

0.00 – 20.99Ω
16.00 – 209.9Ω
160.0 – 2099Ω

Measuring range(Guaranteed
accuracy range)

0 – 2000Ω

Accuracy

Output current

20Ω range; ±2%rdg±0.08Ω
The other ranges: ±2%rdg±3dgt(Auxiliary earth resistance: 100Ω)±2%rdg±0.08Ω
The other ranges:±2%rdg±3dgt

20Ω range: approx. 3mA200Ω range: approx. 1.7mA
2000Ω range: approx. 0.7mA
Frequency: 825Hz

9

CONTINUITY
Range

20.00/200.0/2000Ω (auto-ranging)
0.00 - 20.99Ω
16.0 - 209.9Ω
160 - 2099Ω

Display range
Measuring range(Guaranteed accuracy range)
Accuracy (NULL enabled)
Open-circuit voltage (DC)0 – 2000Ω±2.0%rdg±8dgt
7 – 14V
200mA test: 200mA or more (2Ω or less)
15mA test: 15mA±3mA (short-circuit)

Test current● Enabled if pre-set NULL value is 9Ω or less.
● 2Ω Buzzer: Buzzer sounds when measured resistance is 2Ω or less.
INSULATION(1) INSULATION RESISTANCE
Rated
measurement
voltage
Range
Display range

100V

250V

2.000/20.00/200.0MΩ
auto-ranging
0.000 - 2.099MΩ
1.60 - 20.99MΩ
16.0 - 209.9MΩ

Measuring range(Guaranteed
accuracy range)

0 - 200MΩ

Accuracy

2.000MΩ range: ±2%rdg±6dgt
20.00MΩ range: ±2%rdg±6dgt
200MΩ range: ±5%rdg±6dgt

Rated
measurement
current

1.0 - 1.2mA
at 100kΩ

500V

20.00/200.0/1000MΩ 20.00/200.0/2000MΩ
auto-ranging
auto-ranging
0.00 - 20.99MΩ 0.00 - 20.99MΩ
16.0 - 209.9MΩ 16.0 - 209.9MΩ
160 - 1049MΩ 160 - 2099MΩ
0 - 1000MΩ

1.0 - 1.2mA
at 250kΩ

1000V

0 - 2000MΩ

20.00MΩ range: ±(2%rdg+6dgt)
200.0MΩ range: ±(2%rdg+6dgt)
1000MΩ range: 2000MΩ range:±(5%rdg+6dgt) ±(5%rdg+6dgt)
1.0 - 1.2mA
at 500kΩ

1.0 - 1.2mA
at 1MΩ

● Open-circuit voltage: 100 – 120% of rated measurement voltage● Short-circuit current: within 1.5mA● The tester outputs negative voltage from LINE terminal and positive voltage from
EARTH terminal.
● Max. capacitive load: 1μF: capacitive load dischargeable within 10 sec after test
(IEC 61010-2-034)● Discontinuous beeps sound during a measurement on 1000V range.

10(2) SPD test
Range
Display range
Measuring range
Accuracy
Voltage increase rate
Voltage increase stepThreshold value for current detection

1000V
1049V
0 - 1049V±5%rdg±5dgt
100V / sec.
Increases by 1V.
1mA

LOOP ATT
Function
Mains input
voltage range
LOOP
Range
PFC/PSC
LOOP
Display range
PFC/PSC
Measuring range(Guaranteed
accuracy range)

LOOP

3-Wire L-PE
2-Wire L-PE
100 – 260V 50/60Hz
48 – 260V 50/60Hz(L-N < 20Ω)
20.00/200.0/2000Ω (auto-ranging)
2000A/20kA
2000A/20kA (PFC only)
0.00 – 20.99Ω
0.00 –20.99Ω
21.0 – 209.9Ω
21.0 –209.9Ω
210 – 2099Ω
210 –2099Ω
0 – 2099A
0 – 2099A
2.10 – 20.99kA
2.10 – 20.99kA(PFC only)
0 – 2000Ω0 – 2000Ω

230V+10%-15%:
230V+10%-15%:±(3%rdg+6dgt)±(3%rdg+10dgt)
LOOP
Other than above voltages: Other than above voltages:
Accuracy±(3%rdg+8dgt)±(3%rdg+15dgt)
Depending on the accuracies of voltage and LOOPPFC/PSC
measurements
L-N:6A/60ms
N-PE:10mA (5.3Hz)
Test current
L-PE: 15mA
@230V
EV modeNormal I N-PE:6mA (5.3Hz)
Low I N-PE:4mA (5.3Hz)* If a reading is unstable, one upper range digit might be used instead of the display
range to be used.
* For LOOP 3W EV Normal I, ±2dgt is added to the accuracy listed in above table.
For Low I, errors may be larger as it will be more susceptible to noise.

11

LOOP HIGH
Function
Mains input
voltage range
LOOP
Range
PFC/PSC

Displayrange

Measuring
range(Guaranteed
accuracy
range)

Accuracy

LOOP
PFC/PSC

LOOP

LOOP

PFC/PSC
Test current@230V

L-PE0.01ΩRes
48 - 260V
50/60Hz20.00/200.0/2000Ω
2000A/20kA(PFC only)
0.00 - 20.99Ω
21.0 - 209.9Ω
210 –2099Ω
0 - 2099A
2.10 - 20.99kA(PFC only)

L-PE0.001ΩRes
100 - 260V
50/60Hz2.000Ω
2000A/50kA(PFC only)

L-N/L-L
48 - 500V
50/60Hz20.00Ω
2000A/20kA(PSC only)

0.000 - 2.099Ω

0.00-20.99Ω

0 - 2099A
2.10 - 52.49kA(PFC only)

0 - 2099A
2.10 - 20.99kA(PSC only)

0 – 2000Ω0 – 2Ω

0 – 20Ω

230V+10%-15%:
230V+10%-15%:±(3%rdg+4dgt)
230V+10%-15%:±(3%rdg+4dgt)
100V or less:±(3%rdg+25mΩ)
100V or less:±(5%rdg+15dgt) Other than above ±(5%rdg+15dgt)
Other than above
voltages:
Other than above
voltages:±(5%rdg+35mΩ)voltages:±(3%rdg+8dgt)±(3%rdg+8dgt)
Depending on the accuracies of voltage and LOOP
measurements
20Ω: 6A/20ms
200Ω: 0.5A/20ms
25A/20ms
6A/20ms
2000Ω:
15mA/500ms* If a reading is unstable, one upper range digit might be used instead of the display
range to be used.

12

RCD
(1) Mains input voltage range: 100V – 260V 50/ 60Hz
For Type AC and A RCDs rated at 100mA or higher: 190 – 260V
(2) Accuracy
Test current
Duration
Rated residual operating
RCD
Mode Typecurrent (mA)
Current value Accuracy @230V Measuring
Accuracy(I⊿n)(mA) rms
time
G 10/30/100/300/500/1000-8% to-2%
ACI⊿n×1/2
VAR:-10% to 0%
S
10/30/100/300/500
×1/2

A/F
B
AC

G

10/30/100/300/500

S

10/30/100/300/500

G

10/30/100/300

S

10/30/100/300

G 10/30/100/300/500/1000
S

10/30/100/300/500

G

10/30/100/300/500

S

10/30/100/300/500

G

10/30/100/300

S

10/30/100/300

G

10/30/100

S

10/30/100

G

10/30/100

S

10/30/100

G

10/30

S

10/30

G

10/30/100/300/500

S

10/30/100/300/500

Ramp A/F G
20% toS
110%
G(EV 30% B S
to 100%)10/30/100/300/500

×1

A/F
B
EV
AC

×5

A/F
B
AC

EV

6

10/30/100/300/500
10/30/100/300
10/30/100/300
6I⊿n×0.35-10% to 0%

I⊿n×1/2-10% to 0%I⊿n+2% to +8%
VAR:0% to +10%10mA: I⊿n×2
Other currents:
I⊿n×1.4

0% to +10%I⊿n×2

0% to +10%I⊿n0% to +10%I⊿n×5

+2% to +8%
VAR:0% to +10%

I⊿n×5×1.4

0% to +10%I⊿n×2×5

0% to +10%I⊿n

-4% to +4%

10mA:I⊿n×2
Other currents:
I⊿n×1.4-10% to +10%I⊿n×2

-10% to +10%I⊿n-10% to +10%

2000msG:550ms
S:1000ms

Trip Time±(1%+2ms)
Measuringtime±3% of FS

10.5s

410ms

by 10%
G: 300ms
S: 500ms
by 2%
150ms
by 2%
500ms
(10s is kept
only at 100%)

Measuringtime±3% of FS

・AUTO-TEST：X1/2(0°)→X1/2(180°)→X1(0°)→X1(180°)→X5(0°)→X5(180°)
The test of "X5" will be skipped when a current is 100mA or higher.
At the auto-test for Type EV, additional 6 mA DC test is performed.
Current waveform of KEW 6516/6516BT・Type AC: Test current is sine wave.
・Type A and F: Test current is half sine wave.
・Type B and EV: Direct current

13(3) Uc(RCD)
Mains input voltage range
Range
Display range
Measuring range(Guaranteed accuracy range)
Accuracy
Test current

100-260V
100V
0.0 - 104.9V
0 - 100V+5% to+15%rdg±8dgt @230V
50 % or less of IΔnPossible number of tests with fresh batteries.
CONTINUITYINSULATION RESISTANCE
LOOP
RCD
EARTH
VOLTS/PHASE ROTATION: Approx. 2000 times min. at load 1Ω
: Approx. 1500 times min. at load 1MΩ (1000V): Approx. 3000 times min. (ATT L-PE 3W): Approx. 3500 times min. (G-AC X1 30mA): Approx. 3000 times min. at load 10Ω
: Approx. 40h

5.2 General specification
Specifications are based on the following conditions except
where otherwise stated:1. Ambient temperature: 23±5°C:
Reference conditions 2. Relative humidity: 45% to 75%
3. Nominal voltage of distribution system (Un) :230V/400V, 50Hz/60Hz
4. Altitude: Less than 2000m
Instrument dimensions 235 X 136 X 114mm
Instrument weight
1350g (including batteries)
Battery type
Size AA Alkaline battery (LR6) x 8
Operating temperature -10 to +50°C, relative humidity 80% or less, no condensationand humidity
Storage temperature-20 to +60°C, relative humidity 75% or less, no condensationand humidity
Display
Color Dot Matrix LCD 320(W) X 240(H) pixels.
The continuity test circuit is protected by a 0.5A/600V fast
acting (HRC) ceramic fuse mounted in the battery
Overload protection
compartment, where a spare fuse is also stored.
The insulation resistance test circuit is protected by aresistor against 1000V AC for 10 seconds.

145.3 Applied standards
Instrument operating
IEC61557-1,2,3,4,5,6,7,10
Standard
IEC 61010-1, -2-030, -2-034
CATIII (600V) CATIV (300V) -Instrument
IEC 61010-031
Model 7218A…CAT II 250V
Model 7246 …CATIII 600V/ CATIV300V
Model 7228A…CATIII 300V
Model 7281 …CATIII 600V/ CATIV300V (w/ cap)
…CAT II 1000V (w/o cap)
Safety standard…CAT II 1000V (w/ 8017A)(Attach the supplied protective cap to use this test leads in CAT
III or higher environments.)* When test leads, sometimes with metal tips, are connected
and used with the instrument, the measurement category andvoltage rating of the lowest rated item is applied.
Protection degree
IEC 60529 IP40
EMC
EN 61326-2-2
Environmental standard EU RoHS Directive compliant
This manual and product may use the following symbols adopted from International
Safety Standards;
Measurement category "CAT II" applies to;Electrical circuits of equipment connected to an AC electrical outlet by apower cord.
Measurement category "CAT III" applies to;
CAT III Primary electrical circuits of the equipment connected directly to the
distribution panel, and feeders from the distribution panel to outlets.
Measurement category "CAT IV" applies to;
CAT IV The circuit from the service drop to the service entrance, and to the power
meter and primary overcurrent protection device (distribution panel).
Equipment protec ted throughout by DOU B LE INSU L ATIO N or
REINFORCED INSULATION;
CAT II#

Caution (refer to accompanying documents)
Caution, risk of electric shock
Protection against wrong connection is up to 600V

Earth Ground
Complies with WEEE Directive (2002/ 96/ EC) marking requirements. (valid
in each EU country)

To ensure safe operation of measuring instruments, IEC 61010 establishes safety
standards for various electrical environments, categorized as O to CAT IV, and calledmeasurement categories. Higher-numbered categories correspond to electricalenvironments with greater momentary energy, so a measuring instrument designed for
CAT III environments can endure greater momentary energy than one designed for CAT II.

15

O (None, other)
CAT IICAT IIICAT IV: Circuits which are not directly connected to the mains power supply.
: Electrical circuits of equipment connected to an AC electrical outlet
by a power cord.
: Primary electrical circuits of the equipment connected directly tothe distribution panel, and feeders from the distribution panel tooutlets.
: The circuit from the service drop to the service entrance, and to thepower meter and primary overcurrent protection device (distribution
panel).

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

5.4 Operating uncertainty
Continuity (EN61557-4)
Operating range compliant with EN61557-4
operating uncertainty
0.20 to 2000Ω

Maximum percentage operating
uncertainty±30%

The influencing variations used for calculating the operating error are denoted as follows;
Temperature: 0℃ and 35℃
Supply voltage: 8V to 13.8V
Insulation Resistance (EN61557-2)
Volt
100V
250V
500V
1000V

Operating range compliant with
EN61557-2 operating uncertainty
0.100 to 200.0MΩ
0.250 to 200.0MΩ
0.50 to 1000MΩ
1.00 to 2000MΩ

Maximum percentage
operating uncertainty±30%

The influencing variations used for calculating the operating error are denoted asfollows;
Temperature: 0℃ and 35℃
Supply voltage: 8V to 13.8V

16

Loop Impedance (EN61557-3)

Operating range compliant
with EN61557-3 operating
uncertainty
L-PE 0.01Ω Res
0.40 to 2000Ω
HIGH L-PE 0.001Ω Res
0.400 to 1.999Ω
L-N/L-L
0.40 to 20.00Ω
2Wire
1.00 to 20.00Ω
ATT
3Wire (Except for EV)
0.40 to 2000Ω
Function

Maximum percentage
operating uncertainty±30%

The influencing variations used for calculating the operating error are denoted as follows;
Temperature: 0℃ and 35℃
Phase angle: At a phase angle 0° to 30°
System frequency: 49.5Hz to 50.5Hz
System voltage: 230V+10%-15%
Supply voltage: 8V to 13.8V
Harmonics: 5% of 3rd harmonic at 0°phase angle
6% of 5th harmonic at 180°phase angle
5% of 7th harmonic at 0°phase angle
DC quantity: 0.5% of the nominal voltage
RCD (EN61557-6)
Function
X1/2
X1, X5
Ramp

Operating uncertainty of trip current-10% to 0%
0% to +10%
-10% to +10%

The influencing variations used for calculating the operating error are denoted as follows.
・Temperature : 0℃ and 35℃・Earth electrode Resistance (shall not exceed below) :IΔnType AC
Type A/F
Type B
Type EV
6mA
400Ω
10mA
400Ω
200Ω
40Ω
30mA
100Ω
40Ω
10Ω
100mA
40Ω
20Ω
10Ω
300mA
40Ω
20Ω
2Ω
500mA
40Ω
20Ω
1000mA20Ω
・System voltage: 230V+10%-15%
・Supply voltage : 8V to 13.8V
Earth Resistance (EN61557-5)
Operating range compliant with EN61557-5
operating uncertainty
5.00 to 1999Ω

Maximum percentage operating
uncertainty±30%

The influencing variations used for calculating the operating error are denoted as follows;・Temperature : 0℃ and 35℃・Series interference voltage : 16·2/3Hz, 50Hz, 60Hz, DC:10V
400Hz: 3V・Resistance of the probes and auxiliary earth electrode resistance: 100 x RA, 50kΩ or less・Supply voltage : 8V to 13.8V

17

5.5 Symbols and marks displayed on the LCD
Battery level indicator
Temperature monitor for internal resistance, available atLoop, RCD function. Further measurements are suspended
until the "" symbol disappears.
Measurements in progress
Live Circuit
PE Hi V
L-N >10Ω

N - PE Hi V
Uc > UL

noLive circuit warning (Continuity / Insulation / Earth Function)
Caution: Presence of 100V or more at PE terminal, appears
when touching the Touch Pad
Alert: Presence of 10Ω or more between Line - Neutral at
ATT measurement
Caution: Presence of noise in the circuit under test during
ATT measurement.
Caution: Presence of high voltage between NEUTRAL EARTH during LOOP ATT measurement.
Caution: Uc at RCD test is exceeding the preset UL value(25 or 50V).
Error message: When on the RCD function, RCD tripped
before measuring RCD trip time. Selected IΔn value may
not be correct.
When on the LOOP, PSC/PFC function, supply may havebeen interrupted.
Wiring check for LOOP, RCD function

RH Hi, Rs Hi
No 3-phase system
N-PE Hi Ω

Judged result of each test
: Satisfied the reference value,: Unsatisfied.
: Unjudgeable: Measured result exceeds the measuring
range, and the upper limit of the measuring range issmaller than the reference value.
Appears when setting PAT for Continuity/Insulation function
and limit value for LOOP measurement.
Appears when a Probe resistance of H terminal (RH) orof S terminal (RS) at Earth measurement is exceeded themeasurable range.
Appears to indicate wrong connection at Phase Rotation
check.
For RCD Type B and EV, appears to indicate too highresistance exists between N-PE to apply test current.

18

6. Setup modeEnter in the SETUP mode to make settings of the instrument. The following settings arechangeable.
(1) LANGUAGE .............. Language selection(2) TIME ......................... Clock adjustment(3) LCD Contrast ............ LCD contrast adjustment LCD(4) LCD Backlight ........... LCD backlight brightness adjustment LCD(5) UL value .................... Selects a UL value for RCD function(6) Touch Pad ................. Enables / disables Touch Pad function
Setting method:(1) Press F4 "SETUP" while the start-up screen is displayed (approx. 2 sec.) after
turning on the instrument.
(2) SETUP screen appears. (See Fig. 6-2.)
The screen also can be referenced in the HELP menu: press F4 while the LCD is
showing wiring configuration diagram.

Selected item
is highlighted
in white.

Fig.6-1

Press F4.

Fig.6-2(3) Press ▲(F1) or ▼(F2) switch for item selection and confirm the selection with
ENTER switch.
(4) Press ▲(F1) or ▼(F2) switch and change settings. The changeable settings are as
follows.
Item
LANGUAGETIME
LCD Contrast
LCD Backlight
UL value
Touch Pad

Setting
ENGLISH, FRENCH, POLISH, ITALIAN, SPANISH,
TURKISH, DUTCH, CZECH
Adjusts day, month, year, minute and hour.
Up or Down
Up or Down
25V or 50V
ON or OFF

(5) Press ENTER when settings are done. Then the screen returns to the SETUPMENU screen as Fig. 6-2. Press ESC to cancel the changes.
(6) Pressing ESC on SETUP MENU screen (Fig. 6-2) gets the instrument in stand-by
mode.
Note: Selectable language may not be the same as listed above depending on the
countries and regions.

19

7. Getting started
7.1 Attaching metal tip/ adapter for test leads
The following metal tips and adapters are user-changeable depending on measurement
purposes.
(1) For Model 7281
The following metal tips are available.
1. Standard metal tip
Installed at a shipment supplied with a detachable
insulation cap.
2. Model 8017A
Long type and helpful to access the distant point.
[How to replace the parts]
Turn the tip of Model 7281 counter-clockwise and remove the metal tip.
Insert the metal tip you want to use into the hexagon hole, and turn the tip part of theprobe clockwise to tighten firmly.

Fig.7-1(2) For Model 7246
Either of the following adapters can be attached to.
1. Alligator clip
2. Test probe
Alligator clip

Banana plugs, both ends

Fig.7-2

Test probe# DANGER
To avoid getting electrical shocks, disconnect the test leads from the instrument before
replacing the metal tip or adapter.

20

7.2 Battery voltage check(1) Please refer to "20. Battery and fuse replacement" in this manual and insert
batteries in the instrument.
(2) Press Power switch to turn on the instrument.
(3) Check the battery status indicator displayed at the upper right corner of the LCD.
"
" : Normal. Battery voltage is enough.
"" : Low battery voltage: For continuous measurement, please refer to"20. Battery and fuse replacement" and replace the batteries withnew ones.
"": Battery voltage is below the lower limit of the operating voltage.
In such a condition, accuracy of the measured result isn't guaranteed.
Replace batteries with new ones immediately.
●Battery status indicator might change from "" to "" during a measurement
depending on measured objects; for example, resistance of the object is low.
7.3 Clock adjustment
KEW 6516/ 6516BT has clock function. Time isdisplayed in the upper right corner of the LCD.
Time display format: Day/ Month/ Year / Hour: Min
Enter the SETUP mode to adjust clock. Press ENTER
when clock adjustment is done.
See "6. Setup mode" for further detail of "SETUP"
mode.
(1) On the clock adjustment screen (Fig. 7-4), selectthe parameter (day/ month/ year/ hour/ min) to be
adjusted with ◀(F3) or ▶(F4) switch.
(2) Use ▲(F1) or ▼(F2) switch to alter the value of theselected parameter and press ENTER to confirm.
(Pressing ESC switch during the adjustment can
one step back.)

Clock

Fig.7-3

Fig.7-4 Clock adjustment
Note:
Clock setting will be cleared if no batteries were inserted in the instrument 10 min. or
longer. When battery replacement is required, be careful not to exceed this period. If theclock setting is cleared and restored to the default, please do the setting again.

21

7.4 Help function
With this function, correct connection for each test can be displayed on the LCD.
To check a connection diagram;(1) Make settings of measurement parameters on each function, hold down HELP
(ENTER) switch 1 sec.
(2) Then the LCD shows a connection diagram.

Fig.7-5 Connection diagram example(3) When several connections are available, press F1 switch to toggle the diagrams.
(4) Press ESC to close the currently displayed connection diagram screen.
● The SETUP screen for making each setting will appear by pressing F4 (SETUP)
switch while the LCD is showing a connection diagram.

22

8. Continuity (resistance) tests# DANGER
Do not apply voltage to the continuity function. Always check the circuit or equipment
under test is surely de-energized before starting a measurement.
8.1 Test procedure
The object of continuity testing is to measure only the resistance of the parts of thewiring system under test. This measurement should not include the resistance of any
test leads used. The resistance of the test leads needs to be subtracted from any
continuity measurement. The KEW 6516/ 6516BT is provided with a continuity nullfeature which allows automatic compensation for any test lead resistance.
You should only use the test leads supplied with the instrument.
LCD display and function switches
Switches on / off NULL
function
Switches on / off 2Ω
F2
buzzer
Pat mode setting
F3(OFF, 0.1Ω, 0.3Ω,1Ω)
Test current setting
F4
200mA or 15mA
F1

Measured value

Fig.8-1
Proceed as follows:(1) Select the continuity test by turning the rotary switch.
(2) Insert the test leads to the L and PE terminals on KEW 6516/ 6516BT respectively
as shown in Fig.8-2.

Red

L terminal
Red cord of Model 7246, orModel 7281 Remote Test LeadPE terminal
Green cord of Model 7246

Green
Fig.8-2(3) Connect the ends of the test leads firmly together (see Fig. 8-3) and press andlock down the test switch. The value of the lead resistance will be displayed. The"" symbol is displayed to the left of the reading during a measurement.

23

Fig.8-3(4) Press the F1(NULL) switch, this will null out the lead resistance and the indicatedreading should go to zero.
(5) Release the test switch. Press the test switch and ensure the display reads zero
before proceeding. While using the Continuity null function, "NULL ON" is displayedon the LCD as indicated in Fig.8-3.
●The null value will be stored even if the instrument is powered off.
●This memorized null value can be cancelled by disconnecting the test leads andpressing F1(NULL) switch with the test switch pressed or locked.
●When this is cancelled you will know because NULL OFF is displayed on the LCD.
# CAUTION
Before taking any measurements always check the leads have been zeroed.
(6) Connect the test leads to the circuit whose resistance is required (see Fig. 8-4 for atypical connection arrangement), having first made sure that the circuit is not live.
Note that "Live Circuit" warning will be displayed on the LCD if the circuit is live - butcheck first anyway!

Fig.8-4 Example of continuity test for main equipotential bonding.

24

(7) Press the test switch and read the circuit resistance from the display. The reading
will have the test lead resistance already subtracted if the Continuity null function
has been used.
Note: If the reading is greater than 2099Ω the over range symbol '>' will remain
displayed.
# WARNING
The results of measurements can be adversely affected by impedances of additional
operating circuits connected in parallel or by transient currents.

Fig.8-5● Circuit protection
The instrument has circuit protection function: even if touching with a live circuit
during low-resistance measurement unintentionally, the instrument will have nodamage. That is, the instrument is protected and not be damaged if the open
measuring terminals are connected to a live wire.
8.2 2Ω Buzzer () function
Use F2 switch to enable () / disable () the 2Ω Buzzer. The buzzer sounds
when measured resistance is 2Ω or less while this function is enabled. The buzzer does
not sound if it is disabled.
8.3 Switching test currents
KEW 6516/ 6516BT can perform continuity test at 200mA and also 15mA. Press F4
switch to switch the current between 200mA and 15mA.
8.4 Pat function
PAT function is available to do continuity test for portable appliances,(1) Press F3 to select the criteria value for PAT test. (See the table below.)
Item
Criteria of judgement
PAT OFFPAT 0.1Ω
"✓" : 0.1Ω or less"X" : over 0.1Ω
PAT 0.3Ω
"✓ ": 0.3Ω or less"X" : over 0.3Ω
PAT 1Ω
"✓" : 1Ω or less"X" : over 1Ω25

(2) Make connections as Fig. 8-6 shows to check continuity.
At a PAT testing, "✓" or "X" will be displayed next to the reading to show PASS/
FAIL.

N

L
E

Fig.8-626

9. Insulation tests
This instrument is used to measure insulation resistance of electric appliance or circuit
to inspect the insulation performance. Check the voltage rating of the object to be tested
before making measurement and select the voltage applied to.
● Depending on the object to be measured, displayed insulation resistance value may
not stabilize.
● The instrument may give bleep during an insulation resistance measurement;
however, this is not a malfunction.
● Measurement time may be longer when measuring a capacitive load.
● In insulation resistance measurement, the earth terminal outputs positive voltage andthe line terminal negative voltage.
● Connect the earth lead to the earth (ground) terminal at measurement. It is
recommended to connect the positive side to the earth side when measuring
insulation resistance against ground or when a part of the object under test isearthed. Such connection is known to be more suitable for insulation testing since
insulation resistance values measured with the positive side connected to earth are
typically less than those taken through the reversed connection.
# DANGER● Be extremely careful not to touch the tip of test probe or the circuit under test to
avoid electrical shock during insulation measurement since high voltage is present
at the tip of the test probe continuously.
Wipe the test probe with a soft cloth, if it is wet, and use it after it's dry.
● The battery compartment cover must be closed before you operate the instrument.
# CAUTION
Always disconnect power to the equipment under test before starting insulation
measurement. Do not attempt to make measurements on a live circuit; otherwise, it
may damage the instrument.

27

9.1 Measurement method
On the INSULATION function, breakdown voltage of Surge protect device (SPD,VARISTOR) can be tested in addition to normal insulation resistance.
LCD display and function switches
F1
F2
Measured value

F3

1-min value

Test mode selection
Insulation or SPD
Voltage setting(100V, 250V, 500V, 1000V)
Pat mode setting(OFF, PAT CL1, PAT CL2)

DAR/ PI values
Duration

Output voltage

Fig.9-1(1) Select INSULATION function with the rotary switch.
(2) Press F1 switch and select the test you wish to do: "INSULATION" or SPD:"SPD (VARISTOR)".
(3) Press F2 switch and select the desired voltage range.
(When selecting SPD test, the range is fixed to 1000V.)(4) Insert the test leads to the L and PE terminals on KEW 6516/ 6516BT respectively
as shown in Fig. 9-2.

Red

Green

Fig.9-2

L terminal
Red cord of Model 7246, orModel 7281 Remote Test LeadPE terminal
Green cord of Model 7246

(5) Attach the test leads to the circuit or the appliance under test (See Fig. 9-3, Fig. 9-4,
and Fig. 9-5).

Fig. 9-3 Example of Insulation resistance test on 4 wire-3 phase system

28

Fig.9-4

Fig. 9-5 SPD(VARISTOR) test connection(6) If the "Live Circuit" warning is displayed on the LCD and/or the buzzer sounds, do
not press the test switch but disconnect the instrument from the circuit. Make thecircuit dead before proceeding.
(7) Press the test switch, the display will show the insulation resistance of the circuit or
the appliance to which the instrument is connected. At an SPD(VARISTOR) test, theLCD will show a breakdown voltage.
(8) Auto discharge function
This function allows electric charges stored in the capacitor of the circuit under test to
be automatically discharged after measurement. Set the test switch or remote-control
switch to off with the test leads connected.
Discharge can be checked with the blinking "  " symbol and buzzer.
# DANGER
Never touch the circuit under test immediately after measurement.
Capacitances stored in the circuit may cause electric shock. Leave the test leads
connected to the circuit, and do not touch the circuit until blinking "  " goes off.
● Measurement and elapsed time are displayed on the LCD during insulation
resistance measurement: up to 99 min. 59 sec. Note: The time counter stops andfreezes when it reaches to 99 min. 59 sec.; if the elapsed time exceeds 100 min.
● If the reading measured greater than 2099MΩ (209.9MΩ at 100V/ 250V, 1049MΩ at
500V) the over range reading '>' will be displayed.

29

Fig.9-6
9.2 Continuous measurement (Insulation resistance measurement)
For continuous measurement, use the lock-down feature incorporated in the test switch.
Press and turn the test switch clockwise to lock the switch in operating position; tounlock the switch, turn it counter-clockwise.
# DANGER
Be extremely careful not to touch the tips of test leads to avoid getting electrical shock
since high voltage is present continuously.
9.3 Voltage characteristics of measurement terminals
This instrument conforms to IEC61557. This standard defines that the rated
measurement current shall be at least 1mA, and the lower limit of the insulation
resistance maintaining the rated measurement voltage at measurement terminals. (Seethe table below.) This value is calculated by dividing the rated voltage by rated current.
In case that the rated voltage is 500V, the lower limit of the insulation resistance is foundas follows.
Divide 500V by 1mA equals 0.5MΩ.
That is, insulation resistance of 0.5MΩ or more is required to provide the rated voltage
to the instrument.
Rated voltage
100V
Lower limit of the insulation resistance to 0.1MΩ
provide the rated current of 1mA

250V
500V
0.25MΩ 0.5MΩ

Fig.9-7

30

1000V
1MΩ

9.4 DAR/ PI measurement, 1-min value display
DAR (Dielectric Absorption Ratio) and PI (Polarization Index) are automaticallymeasured during insulation resistance measurement.
When measurement time elapsed:- 1 min: LCD shows DAR value.
- 10 min: LCD shows PI value.
The LCD shows the measured value, after 1 min has passed since the start ofmeasurement. Measured value is reviewable when 1 min elapses and also after the endof measurement.
The table below shows the formula and the display range.
FormulaDisplay range

DAR = Resistance (1 min after a start of test) / Resistance (15 sec
after a start of test),
PI = Resistance (10 min after a start of test) / Resistance (1 minafter a start of test)
0.00 to 9.99

*DAR and PI value to be displayed will be "no" if the resistance value applied in theabove formula is 0MΩ or out of display range. When DAR and PI values exceed thedisplay range, the LCD shows ">9.99".
9.5 Pat function
PAT function is available to do insulation test for portable appliances : this function isavailable only on 250V and 500V range.
(1) Press F3 to select the criteria value for PAT test. (See the table below).
Item
PAT OFF

Criteria of judgement-

PAT CL1"✓": 1MΩ or more
"X": less than 1MΩ

PAT CL2"✓": 2MΩ or more
"X": less than 2MΩ

(2) Make connections as Fig. 9-8 and 9-9 show to check insulation.
At a PAT testing, "✓" or "X" will be displayed next to the reading to show PASS/ FAIL.

N

L

N
E

E L

Fig.9-8

Fig.9-931

9.6 SPD(Varistor) test
SPD test can measure a voltage which breakdowns surge protective device(varistor).
When the test gets started, the voltage KEW 6516/6516BT outputs automaticallyincreases from 0 V until the SPD breakdowns and the LCD shows the voltage value.
(If a 1 mA or higher current flow is detected, the instrument judges it is the breakdown
point.)● Press the Test switch to start a measurement. Pressing F4 or ESC switch during ameasurement stops the measurement.
● The LCD shows SPD breakdown voltage (DCV) and also the assumed alternative
voltage (ACV).
The displayed ACV is determined by the following formula.
ACV = DCV/ 1.4● If there's no SPD breakdown, the LCD shows ">1049V".
Breakdown
voltage (DCV)

Breakdown
voltage (ACV)

Fig. 9-10 SPD measurement screen

3210. LOOP/ PSC/PFC
10.1 Principles of measurement(1) Principles of measurement of fault loop impedance and PFC
If an electrical installation is protected by over-current protective devices including circuit
breakers or fuses, the earth loop impedance should be measured.
In the event of a fault the earth fault loop impedance should be low enough (and theprospective fault current high enough) to allow automatic disconnection of the electricalsupply by the circuit protection device within a prescribed time interval. Every circuit
must be tested to ensure that the earth fault loop impedance value does not exceedthat specified or appropriate for the over-current protective device installed in the circuit.
The KEW 6516/6516BT takes a current from the supply and measures the difference
between the unloaded and loaded supply voltages. From this difference it is possible tocalculate the loop resistance.
TT System
For a TT system the earth fault loop impedance is the sum of the following impedances;●Impedance of the power transformer secondary winding.
●Impedance of the phase conductor resistance from the power transformer to thelocation of the fault.
●The impedance of the protective conductor from the fault location to the earth system.
●Resistance of the local earth system (R).
●Resistance of the power transformer earth system (Ro).
The figure below shows (dotted line) the Fault loop impedance for TT systems.

Fig.10-1

33

According to the International Standard IEC 60364, for TT systems the characteristicsof the protective device and the circuit resistance shall fulfill the following requirements:
Ra x Ia ≤ 50V
Where:Ra is the sum of the resistances in Ω of the local earth system and the protective
conductor for the exposed conductive parts.
50 is the maximum safety touch voltage limit (it can be 25V in particular cases likeconstruction sites, agricultural premises, etc.).
Ia is the current causing the automatic disconnection of the protective device within the
maximum disconnecting times required by IEC 60364-41 that, for electrical installationsat 230 / 400V AC, are:- 200 ms for final circuits up to 63A for socket, or up to 32A for fixed connected loads.
- 1 s for distribution circuits and circuits above mentioned over 63A and 32A.
The compliance with the above rules shall be verified by:
1) Measurement of the resistance Ra of the local earth system by Loop tester or Earthtester.
2) Verification of the characteristics and/or the effectiveness of the RCD associatedprotective device.
Generally, in TT systems, RCDs shall be used as protective device and in this case, Ia
is the rated residual operating current IΔn. For instance, in a TT system protected by a
RCD the max Ra values are:Rated residual operating
current IΔnRA (with touch voltage of 50V)
RA (with touch voltage of 25V)

30

100

300

500

1000

(mA)

1667
833

500
250

167
83

100
50

50
25

(Ω)
(Ω)

Shown below is a practical example of verification of the protection by RCD in a TT
system according to the international Standard IEC 60364.

Fig.10-2

34

In this example, the max permissible value is 1667Ω (RCD =30mA and contact voltage
limit of 50V). The instrument reads 12.74Ω, thus the condition RA ≤ 50/Ia is respected.
However, considering that the RCD is essential for protection, it must be tested (Pleaserefer to RCD TESTS section).
TN System
For TN systems the earth fault loop impedance is the sum of the following impedances.
●Impedance of the power transformer secondary winding.
●Impedance of the phase conductor from the power transformer to the location of thefault.
●Impedance of the protective conductor from the fault location to the powertransformer.
The figure below shows (dotted line) the Fault loop impedance for TN systems.

Fig.10-3
According to the International Standard IEC 60364, for TN system the characteristics ofthe protective device and the circuit impedance shall fulfill the following requirement:
Zs x Ia ≤ Uo
Where:
Zs is the Fault loop impedance in ohm.
Uo is the nominal voltage between phase to earth (typically 230V AC for both single
phase and three phase circuits).
Ia is the current causing the automatic disconnection of the protective device within the
maximum disconnecting times required by IEC 60364-41 that, for installation at 230 /400V AC, are:- 400 ms for final circuits up to 63A for socket, or up to 32A for fixed connected loads.
- 5 s for distribution circuits and circuits above mentioned over 63A and 32A.
The compliance with the above rules shall be verified by:
1)Measurement of the fault loop impedance Zs by Loop tester.
2)Verification of the characteristics and/or the effectiveness of the associated protective
device. This verification shall be made:- for circuit-breakers and fuses, by visual inspection (i.e. short time or instantaneous
tripping setting for circuit-breakers, current rating and type for fuses);- for RCDs, by visual inspection and test using RCD testers recommending that thedisconnecting times mentioned above are met (Please see RCD TEST section).

35

For instance in a TN system with nominal voltage at 230 / 400V AC and protected by fuseor circuit breaker, knowing the curves characteristic of the gG fuses or MCBs (Miniature
Current Breakers according to IEC60898-1 and IEC60947-2) the max Zs values could be:
Protection
deviceDisconnection
time
6A
10A
13A
16A
20A
25A
Rating
32A
35A
40A
50A
63A
80A
100A

gG Fuses

B

C

C

MCBs

D

D

K

0.4s

5s

0.4 & 5s

0.4s

5s

0.4s

5s

0.4s

5.00Ω
2.87Ω
2.30Ω
2.15Ω
1.58Ω
1.27Ω
0.84Ω
0.74Ω
0.72Ω
0.49Ω
0.42Ω
0.27Ω
0.22Ω

8.84Ω
5.00Ω
4.10Ω
3.48Ω
2.65Ω
2.11Ω
1.44Ω
1.36Ω
1.21Ω
0.87Ω
0.72Ω
0.51Ω
0.39Ω

7.67Ω
4.60Ω
3.53Ω
2.87Ω
2.30Ω
1.84Ω
1.44Ω
-1.15Ω
0.92Ω
0.73Ω
0.58Ω
0.47Ω

3.83Ω
2.30Ω
1.77Ω
1.44Ω
1.15Ω
0.92Ω
0.72Ω
-0.57Ω
0.46Ω
0.36Ω
0.29Ω
0.23Ω

7.67Ω
4.60Ω
3.53Ω
2.87Ω
2.30Ω
1.84Ω
1.44Ω
-1.15Ω
0.92Ω
0.73Ω
0.58Ω
0.47Ω

1.92Ω
1.15Ω
0.88Ω
0.72Ω
0.57Ω
0.46Ω
0.36Ω
-0.28Ω
0.23Ω
0.18Ω
0.15Ω
0.12Ω

3.83Ω
2.30Ω
1.77Ω
1.44Ω
1.15Ω
0.92Ω
0.72Ω
-0.57Ω
0.46Ω
0.36Ω
0.29Ω
0.23Ω

2.73Ω
1.64Ω
1.18Ω
1.26Ω
0.82Ω
0.61Ω
0.51Ω
-0.41Ω
0.33Ω
0.26Ω
0.20Ω
0.16Ω

The most complete Multifunction testers also have such above Zs limit table implemented
in their firmware, so that the verification of the overcurrent protection is automaticallymade by comparing the measured value of Loop impedance and the Zs limit of the table.
Note : Applicable Zs limit table varies country by country. KEW 6516/ 6516BT automaticallyshows the appropriate Zs limit table corresponding to the selected language.
Below is a practical example of verification of the protection by MCB in a TN system
according to the international Standard IEC 60364.

Fig.10-4

36

Max value of Zs for this example is 1.44Ω (MCB 16A, characteristic C), the instrument
reads 1.14Ω (or 202A on Fault current range) it means that the condition
Zs x Ia ≤ Uo is respected.
In fact the Zs of 1.14Ω is less than 1.44Ω (or the Fault current of 202A is more than Iaof 160A).
In other words, in case of fault between phase and earth, the wall socket tested in thisexample is protected because the MCB will trip within the disconnection time required.
(2) Principles of the measurement of line impedance and PSC
The method for measuring Line – neutral impedance and line-line impedance is exactly
the same as for earth fault loop impedance measurement with the exception that themeasurement is carried out between line and neutral or line and line.
Prospective short circuit or fault current at any point within an electrical installationis the current that would flow in the circuit if no circuit protection operated and acomplete (very low impedance) short circuit occurred. The value of this fault current
is determined by the supply voltage and the impedance of the path taken by the fault
current. Measurement of prospective short circuit current can be used to check that theprotective devices within the system will operate within safety limits and in accordancewith the safe design of the installation. The breaking current capacity of any installed
protective device should be always higher than the prospective short circuit current.

Fig.10-537

10.2 Measurement method for LOOP high current
LCD display and function switches
Switches measurement mode:
L-PE or L-N/L-L
Selects resolution 0.01Ω or 0.001Ω
F2(In case of L-PE)
F3 Selects test lead (0.001ΩRes)
F4 Limit value setting
F1

LOOP limit value
Measured value
PFC or
PSC value

Mains voltage
Wiring check

Fig.10-6(1) Select LOOP HIGH function with the rotary switch.
(2) Connect the test lead into the instrument. (Fig. 10-7 or Fig. 10-8)
L

PE

N

At L-PE measurement,
no need to use N
terminal.

or
RED

GREEN

BLUE
Fig. 10-7 For L-PE and L-N test
L

RED

N

BLUE
Fig. 10-8 For L-N and L-L test38

(3) Press the F1 switch and select L-N to measure L-N/L-L loop impedance or select
L-PE to measure earth loop impedance.
    ・Press F2 switch and select the resolution either 0.01Ω or 0.001Ω at L-PE test.
    ・Display changes automatically as follows depending on the applied voltages while
LOOP(L-N/L-L) is selected.
LOOP
<48V

LOOP
48 – 300V

LOOP
>300V

L-N

L-N/L-L

L-L

Fig.10-9(4) Press F4 switch to enter the setting mode for limit value.
Please refer to "10.4 Loop limit value".
(5) Connection
Connect KEW 6516/ 6516BT to the distribution system to be tested with reference toFig. 10-12, 10-13, 10-14, and 10-15.
(6) Wiring Check
After the connection, ensure that the symbols for Wiring check on the LCD are in thestatus indicated in Fig.10-10 before pressing the test switch.

（

FUNCTION

L-PE○

L-N○

L-PE

◉

◉
or
○
◉
or
◉

）

0.01ΩRes
0.001ΩRes◉◉

L-N/L-L
○

○
○
○
○
○

Fig. 10-10
If the status of the symbols for Wiring check differ from Fig.10-10 or○ symbol isindicated on the LCD, DO NOT PROCEED AS THERE IS INCORRECT WIRING. The
cause of the fault must be investigated and rectified.
When the instrument is first connected to the system, it will display the line-earth voltage(mode L-PE) or line-neutral voltage (mode L-N/ L-L) which is updated every 1s. If thisvoltage is not normal or as expected, DO NOT PROCEED.

39

(7) Test lead selection (L-PE0.001ΩRes)
In case of L-PE0.001ΩRes, use F3 switch to select the test lead to be used. When
0.001ΩRes, the resistance of the test lead to be used affects the measured result;
therefore, test lead selection is effective to reduce errors in results. Select either
Model 7218A Mains test lead or Model 7246 (Distribution board test lead).

Mains lead is selected.

Distribution board lead is selected.
Fig.10-11(8) Measurement
Press the test switch. A beep will sound as the test is conducted and the value ofloop impedance will be displayed. When LOOP limit value has been set, the LCD
shows "✓" when the measured value is lower than the limit value and "X" if the value
exceeds the limit value. The " ! " symbol appears when the measured result exceeds
the measuring range, and the upper limit of the measuring range is smaller than thereference value: it means unjudgeable.
● If the display shows '>' then this usually means the value measured exceeds therange.

Fig. 10-12 Connection for using Outlet

40

Fig. 10-13 Connection for distribution

Fig. 10-14 Connection for Line – Neutral measurement

Fig. 10-15 Connection for Line – Line measurement

41

The test switch may be pressed down and turned clockwise to lock it for auto-test. In
this auto mode, when using distribution board lead Model 7246, tests are conducted bysimply disconnecting and reconnecting the red phase prod of the Model 7246 avoiding
the need to physically press the test switch i.e. 'hands free'.
● Measured result may be influenced depending on the phase angle of the distribution
system when making measurement near a transformer and the result may lower than
the actual impedance value. Errors in measured result are as follows.
System Phase Difference
Error (approx.)
10°
-1.5%
20°
-6%
30°
-13%
) appears, it means that the test resistor is too hot and the●If the symbol (automatic cut out circuits have operated. Allow the instrument to cool down before
proceeding. The overheat circuits protect the test resistor against heat damage.
10.3 Measurement method for LOOP ATT (Anti trip technology)
LCD display and function switches
F1 Switches 3-wire, 3-wire EV & 2-wire Test
F2 Turns on/ off pulse function
Toggles between normal & low current
F3 for EVSE loop testing– only shows if
L-PE 3W EV is selected at F1
F4 Limit value setting

LOOP limit value
Measured value
PFC or
PSC value

Mains voltage
Wiring check

Noise indicator

Fig. 10-16(1) Press the Power switch and turn on the instrument. Turn the rotary switch and set itto the LOOP ATT position.

42

(2) Connect the test lead to the instrument. (Fig. 10-17 or Fig. 10-18)
L

PE

N
or

RED

GREEN

BLUE

Fig. 10-17 For L-PE 3-wire test
L

RED

PE

GREEN

Fig. 10-18 For L-PE 2-wire test(3) Press F1 switch and select either L-PE 2W (2-wire), L-PE 3W (3-wire) or L-PE 3W
EV test.
(4) Pulse function can be turned on or off with F2 switch.
When pulse function is on (enabled), a high current is applied in a short period - RCD
won't trip - before starting LOOP measurement. This pulse function can remove theoxidized coating of the circuit under test and contribute accurate measurements.
# CAUTION
When pulse function is enabled, some RCDs may trip depending on their sensitivity. Insuch a case, turn off the pulse function.
(5) Press F4 switch to enter the setting mode for limit value.
Please refer to "10.4 Loop limit value".
(6) Connection
Connect KEW 6516/6516BT to the distribution system to be tested with reference toFig. 10-20, 10-21 and 10-22.
(7) Wiring Check
After the connection, ensure that the symbols for Wiring check on the LCD are in thestatus indicated in Fig.10-19 before pressing the test switch.
FUNCTION

L-PE○

L-N○

L-PE 3W (EV)L-PE 2W

◉
◉

◉
○

○
○
○

Fig. 10-19
If the status of the symbols for Wiring check differ from Fig. 10-19 or○ symbol isindicated on the LCD, DO NOT PROCEED AS THERE IS INCORRECT WIRING. The
cause of the fault must be investigated and rectified.

43

When the instrument is first connected to the system, it will display the line-earth voltage(mode L-PE) which is updated every 1s. If this voltage is not normal or as expected, DO
NOT PROCEED.
(8) Measurement
Press the test switch. A beep will sound as the test is conducted and the value ofloop impedance will be displayed. When LOOP limit value has been set, the LCD
shows "✓" when the measured value is lower than the limit value and "X" if the value
is higher than the limit value.
●If the display shows '>' then this usually means the value measured exceeds therange.

Fig. 10-20 3-wire test (Connection for using outlet)

Fig. 10-21 3-wire test (Connection for distribution)

44

Fig. 10-22 L-PE 2-wire test
●ATT mode enables a measurement without tripping the RCDs with the rated residual
current of 30mA or more.
● The L-PE 3W EV setting enables loop testing where sensitive DC monitoring devices
are used. Press F 3 to select the test current.
●Measurement in ATT mode requires longer time than that is required for the othermeasurements (approx. 8 sec). When measuring a circuit with a large electricalnoise, the 'Noise' Message is displayed on the LCD and the measurement time will be
extended.
Noise indicator shows the noise size in three levels. Noise size affects themeasurement Time.

Level 1

Level 2

Level 3Fig. 10-23 Noise indicator

If the 'NOISE' symbol is displayed on the LCD, it is recommended to disable the ATTmode and take a measurement (RCDs may trip).
●At L-PE 3W (EV) measurement, when a LOOP impedance between L-N exceeds
20Ω, the LCD shows "L-N>20Ω" and the instrument doesn't make measurements. In
this case, set the range to "LOOP HIGH" or test with L-PE 2W ATT.
●If a high voltage exists between N-PE at L-PE 3W (EV) test, the LCD shows "N-PE
HiV" and the instrument doesn't make measurements. In this case set the range to"LOOP HIGH" or test with L-PE 2W ATT.
The test switch may be turned clockwise to lock it down. In this auto mode, when using
distribution board lead Model 7246, tests are conducted by simply disconnecting andreconnecting the red phase prod of the Model 7246 avoiding the need to physicallypress the test switch i.e. 'hands free'.

45

●Measured result may be influenced depending on the phase angle of the distribution
system when making measurement near a transformer and the result may lower than
the actual impedance value. Errors in measured result are as follows.
System Phase Difference
10°
20°
30°

Error (approx.)
-1.5%
-6%
-13%

)appears, this means that the test resistor is too hot and the●If the symbol (automatic cut out circuits have operated. Allow the instrument to cool down before
proceeding. The overheat circuits protect the test resistor against heat damage.
10.4 Loop limit value
To set a loop limit value, press F4 switch in the stand-by mode at LOOP test. The
following figure shows the setting mode screen.

Fig. 10-24 LOOP LIMIT setting screen
・The table below shows the setting parameters.
(a) Protection type(b) In(c) Time or Uc(d) Factor

Type of protective device
Rated current ofprotective device
Trip time of protective
devicegG FUSE, MCB(B,C,D,K), RCD, OFF
In: 6 - 100 A
IΔn: 30 mA-1000 mA
For RCD, Uc limit value setting

Limit value is determined by the
Margin of threshold value following formula.
Limit = specified value x factor

Limit value setting procedures are shown below.
(Press ESC switch to one step back during the process.)(1) Press F1(▲) or F2(▼) on LOOP LIMIT setting screen to move the cursor on the item
to be set, and then press ENTER switch.
(2) The LCD shows the selectable items. Press F1(▲) or F2(▼) and confirm theselection with ENTER switch. For some items, F3( ) and F4( ) switches are also
used.
(3) When changes are done, press ESC to return to LOOP test screen.

46

Selectable parameters and reference values for limit value are as shown below.
●Loop Limit value for fuse protection
Protection
Type
TIME

In
Rating

6A
10A
13A
16A
20A
25A
32A
35A
40A
50A
63A
80A
100A

gG Fuse
0.4s
5Ω
2.87Ω
2.3Ω
2.15Ω
1.58Ω
1.27Ω
0.84Ω
0.74Ω
0.72Ω
0.49Ω
0.42Ω
0.27Ω
0.22Ω

5s
8.84Ω
5Ω
4.1Ω
3.48Ω
2.65Ω
2.11Ω
1.44Ω
1.36Ω
1.21Ω
0.87Ω
0.72Ω
0.51Ω
0.39Ω

MCB
B
0.4 & 5s
7.67Ω
4.6Ω
3.53Ω
2.87Ω
2.3Ω
1.84Ω
1.44Ω
-1.15Ω
0.92Ω
0.73Ω
0.58Ω
0.47Ω

C
0.4s
3.83Ω
2.3Ω
1.77Ω
1.44Ω
1.15Ω
0.92Ω
0.72Ω
-0.57Ω
0.46Ω
0.36Ω
0.29Ω
0.23Ω

D
5s
7.67Ω
4.6Ω
3.53Ω
2.87Ω
2.3Ω
1.84Ω
1.44Ω
-1.15Ω
0.92Ω
0.73Ω
0.58Ω
0.47Ω

0.4s
1.92Ω
1.15Ω
0.88Ω
0.72Ω
0.57Ω
0.46Ω
0.36Ω
-0.28Ω
0.23Ω
0.18Ω
0.15Ω
0.12Ω

5s
3.83Ω
2.3Ω
1.77Ω
1.44Ω
1.15Ω
0.92Ω
0.72Ω
-0.57Ω
0.46Ω
0.36Ω
0.29Ω
0.23Ω

K
0.4s
2.73Ω
1.64Ω
1.18Ω
1.26Ω
0.82Ω
0.61Ω
0.51Ω
-0.41Ω
0.33Ω
0.26Ω
0.2Ω
0.16Ω

●Loop Limit value for RCD protection

IΔn (mA)

UC Lim.
30mA
100mA
300mA
500mA
1000mA

50V
1667Ω
500Ω
167Ω
100Ω
50Ω

25V
833Ω
250Ω
83Ω
50Ω
25Ω

Note: Displayed Loop Limit value may not be the same as listed above depending on
the countries and regions.

47

11. RCD tests
11.1 Principles of RCD measurement
The RCD tester is connected between phase and protective conductor on the load sideof the RCD after disconnecting the load.
A precisely measured current for a carefully timed period is drawn from the phase andreturns via the earth, thus tripping the device. The instrument measures and displays
the exact time taken for the circuit to be opened.
An RCD is a switching device designed for breaking currents when the residual current
attains a specific value. It works on the basis of the current difference between phasecurrents flowing to different loads and returning current flowing through the neutral
conductor (for a single-phase installation). In the case where the current difference ishigher than the RCD tripping current, the device will trip and disconnect the supply fromthe load.
There are two parameters for RCDs; the first due to the shape of the residual current
wave form (types AC and A) and the second due to the tripping time (types G and S).
●
RCD type AC will trip when presented with residual sinusoidal alternating currents
whether applied suddenly or slowly rising. This type is the most frequently used onelectrical installations.
●
RCD type A will trip when presented with residual sinusoidal alternating currents(similar to type AC) and residual pulsating direct currents whether suddenly appliedor slowly rising.
●
RCD Type F will trip when presented with residual sinusoidal alternating currents
at the rated frequency, residual pulsating direct currents and composite residual
currents.
Tests of RCD type F with F KEW 6516/6516BT use halfwave rectified current assame as testing Type A RCD.
●
RCD type B can detect residual sinusoidal alternating currents up to 1000 Hz,
residual pulsating direct currents as well as smooth DC residual currents.
● RCD type G. In this case G stands for general type (without tripping time delay) andis for general use and applications.
●
RCD type S where S stands for selective type (with tripping time delay). This typeof RCD is specifically designed for installations where the time delay characteristic is
required.
● RCD Type EVs are designed specially for EV (electric vehicle) charging systems.
They trip by 6mA smooth DC residual currents.
Given that when the protective device is an RCD, Ia is typically 5 times the rated
residual operating current IΔn, then the RCD must be tested recommending thetripping time, measured by RCD testers or multifunction testers, shall be lower than the
maximum disconnecting times required in IEC 60364-41 at 230V / 400V AC (see also
LOOP section) that are:TT system
TN system
TT system
TN system

200ms
400ms
1000ms5s

for final circuits up to 63A for socket, or up to 32A
for fixed connected loads
for distribution circuits and circuits above mentioned
over 63A and 32A.

48

However, it is also good practice to consider even more stringent trip time limits, byfollowing the standard values of trip times at IΔn defined by IEC 61009 (EN 61009) andIEC 61008 (EN 61008). These trip time limits are listed in the table below for IΔn and
5IΔn:Type of RCD
General(G)Selective(S)

IΔn
300ms
max allowed value
500ms
max allowed value
130ms
min allowed value

5IΔn
40ms
max allowed value
150ms
max allowed value
50ms
min allowed value

Examples of instrument connections
Practical example of 3-phase + neutral RCD test in a TT system.

Fig. 11-1
Practical example of single phase RCD test in a TN system.

Fig. 11-2

49

Practical example of RCD test with distribution leads.

Fig. 11-3
11.2 Principles of Uc measurement
Ground being imperfect in the Fig. 11-1, when R exists, when a fault current flows to R,
electric potential occurs. There is a possibility the person contacting in this imperfectground, it calls the voltage, which it occurs in the human body of this time, called Uc.
When with the Uc Test letting flow IΔN to the RCD, the Uc is calculated.
Uc voltage is calculated based on the Rated Residual Current (IΔN) with the
impedance measured.
11.3 Measurement method for RCD
LCD display and function switches

F1
F2
F3

F4

Measured

Measurement mode setting(X1/2, X1, X5, Ramp, Auto,Uc)
IΔn setting
RCD Type setting
AC-G
AC-S
A-G
A-S
F-G
F-S
B-G
B-S
TYPE EV
Phase Setting (0° (+)or 180° (-))

Preset UL value

value

L-PE voltage
Wiring check

Fig. 11-4(1) Press the Power switch and turn on the instrument. Turn the rotary switch and set itto the RCD position.

50

(2) Connect the test lead to the instrument. (Fig. 11-5)
L

PE

N

At AC/ A/F measurement,
no need to use N terminal.
or

RED

GREEN

BLUE

Fig. 11-5 For RCD test(3) Press the F1 switch and select any desired measurement mode.
X1/2
X1
X5

For testing RCD to verify that they are not too sensitive.
For measuring the trip time.
For testing at IΔn X5

RAMP(
AUTO
Uc

)

For measuring the tripping level in mA.
For automatic measurement in the following
sequence: X1/2(0°), X1/2(180°), X1(0°),X1 (180°), X5(0°), X5(180°)
For measuring Uc(4) Press the F2 switch to set Rated Tripping Current (IΔn) to the rated trip current of
the RCD.
(5) Press F3 switch to select the RCD type.
Refer to "11.1 Principles of RCD measurement" for the details of RCD type.
(Except for Uc measurement)(6) Press (F4) to select phase at which the test current should start.
(Except for Uc measurement)*UL value change
As a UL value, 25V or 50V is selectable. Refer to "6. Setup mode" in this manual andselect either of them.
(7) Connect the test leads to the circuit to be tested. (Fig. 11-1,11-2, and 11-3)(8) Wiring Check
After the connection, ensure that the symbols for Wiring check on the LCD are in thestatus indicated in Fig.11-6 before pressing the test switch.
RCD TYPE

L-PE○

L-N○

◉

◉
or
○
◉

AC/A/F
B/EV

◉
◉

○
○
○
○

Fig. 11-6○ symbol is
If the status of the symbols for Wiring check differ from Fig. 11-6 orindicated on the LCD, DO NOT PROCEED AS THERE IS INCORRECT WIRING. The
cause of the fault must be investigated and rectified.

51

When the instrument is connected to the system for the first time, it will display the lineearth voltage (mode L-PE) which is updated every 1s. If this voltage is not normal or as
expected, DO NOT PROCEED.
NOTE: This is a single phase (230V AC) instrument and under no circumstances should
it be connected to 2- phases or a voltage exceeding 230VAC+10%.
If the input voltage is greater than 260V the display will indicate '>260V' and
RCD measurements can not be made even if the test switch is pressed.
(9) RCD Measurement
Press the test switch. A beep will sound as the test is conducted and the measured
results are displayed.
● X1/2...................The Breaker should not trip.
● X1......................The Breaker should trip.
● X5......................The Breaker should trip.
● Auto Ramp( )..The Breaker should trip. The tripping current should be displayed.
● Uc......................Uc values are displayed.
In case of RCD type S test, you need to wait 30 sec. before starting a test: this waitingtime is to reduce the influence of the previous test.
(10) Press the F4(0°(+)/180°(-)) switch to change the phase and repeat step (1).
The test switch may be turned clockwise to lock it down. In this auto mode, when using
distribution board lead Model 7246, tests are conducted by simply disconnecting andreconnecting the red phase prod of the Model 7246 avoiding the need to physicallypress the test switch i.e. 'hands free'.
● If the symbol ( )appears, this means that the test resistor is too hot and theautomatic cut out circuits have operated. Allow the instrument to cool down before
proceeding. The overheat circuits protect the test resistor against heat damage.
● Be sure to return the tested RCD to the original condition after the test.
● When the Uc voltage rises to UL value or greater, the measurement is automaticallysuspended and "Uc > UL" is displayed on the LCD.
● If " IΔn" setting is greater than the rated residual current of the RCD, the RCD willtrip and "no" may be displayed on LCD.
● If a voltage exists between the protective conductor and earth, it may influence themeasurements.
● If a voltage exists between neutral and earth, it may influence the measurements,
therefore, the connection between neutral point of the distribution system and earth
should be checked before testing.
● If leakage currents flow in the circuit following the RCD, it may influence themeasurements.
● The potential fields of other earthing installations may influence the measurement.
● Special conditions of RCDs of a particular design, for example S- type, should betaken into consideration.
● The earth electrode resistance of a measuring circuit with a probe shall not exceed
the earth electrode resistance values, specified in the table below RCD-related
description, in 5.4 Operating uncertainty .
● Equipment following the RCD, e.g. capacitors or rotating machinery, may cause asignificant lengthening of the measured trip time.

52

11.4 Auto test
Measurements are automatically performed under the Auto Test function in the following
sequence: X1/2(0°), X1/2(180°), X1(0°),X1 (180°), X5(0°), X5(180°).
(1) Press F1 to select Auto.
(2) Press F2 & F3 to select IΔn & RCD type.
(3) KEW 6516/ 6516BT performs RCD test in the sequence described above.
(4) When an RCD trips, turn it back on. Then a next test begins automatically.
(5) The LCD shows results as follows.

Fig. 11-7
11.5 VAR (variable current value) function
At RCD test with KEW 6516/6516BT, any I∆n value – between 10mA and 1000mA - isselectable. However, X5 test or depending on the selected RCD test settings, variable
range of current value will be limited.
Follow the procedures below to change the current value.
(Pressing ESC switch during the changing process can one step back.)(1) Press F1 & F3 to select measurement mode & RCD type.
(2) Press F2 switch to select "VAR".
(3) The LCD shows current value 2 sec. (Fig. 11-8). Press F1 (SET) switch within this2 sec. (If 2 sec or longer are elapsed without pressing the switch, press F2 switch
again to reshow Fig. 11-8 screen.)(4) The LCD shows current value changing screen (Fig. 11-9). Press F3( ) or F4( ) to
select the digit to be changed and alter the values with F1(▲) or F2(▼).
(5) Press ENTER to confirm the change. Then the screen returns to stand-by mode for
RCD test.

Fig. 11-8

Fig. 11-9

Note: At VAR test, X1/2, X1, and X5 tests are performed; these tests are not available at
Uc, AUTO, and RAMP tests.

53

11.6 EV RCDWhen selecting EV for RCD TYPE, the instrument can test RCDs for EV charger
which trip by 6 mA DC: x1, RAMP( ), and AUTO TEST are selectable.
● At RAMP, current is steadily increased up to 6 mA DC (100%).
When it reaches to 6 mA DC, the current is kept for 10 sec. (Comply with
IEC62752)● At AUTO TEST, the instrument performs tests at 6 mA DC and ×1/2, ×1, and ×5
tests at 30 mA AC as shown below.
DC6mA(+) → DC6mA(-) → X1/2(0°) → X1/2(180°) → X1(0°) →X1(180°) →X5(0°) → X5(180°).
AC30mA

Fig. 11-10

12. Earth tests
12.1 Principles of earth measurement
This Earth function is to test power distributionlines, in-house wiring system, electricalappliances etc.
This instrument makes earth resistancemeasurement with fall-of-potential method,which is a method to obtain earth resistancevalue Rx by applying AC constant current
I between the measurement object E (earth
electrode) and H(C) (current electrode), andfinding out the potential difference V between E
and S(P) (potential electrode).
Rx = V / I

Constant Current Generator
Voltmeter
S(P)Potential H(C)Current

E(Earth)Fig. 12-1

12.2 Earth resistance measurement# WARNING
The instrument will produce a maximum voltage of about 50V between terminals
E-H(C) in earth resistance function. Take enough caution to avoid electric shock
hazard.
# CAUTION
When measuring earth resistance, do not apply voltage between measuring terminals.

5412.3 Measurement method for earth(1) Press the Power switch and turn on the instrument. Turn the rotary switch and set itto the EARTH position.
(2) Press F1 switch to select 3W (3-wire precise measurement) or 2W (2-wire simplified
measurement).
(3) Connect the test lead into the instrument. (Fig. 12-2, Fig. 12-3)
Red

Green

Yellow

H(C)

E

S(P)

H(C) terminal
Red cord of Model 7228
E terminal
Green cord of Model 7228
S(P) terminal
Yellow cord of Model 7228

Fig.12-2 For 3W test (Precise measurement)

H(C)H(C) terminal
Red cord of Model 7246, orModel 7281 Remote Test Lead
E terminal
Green cord of Model 7246

E

Fig.12-3 For 2W test (Simplified measurement)(4)Connection
3W test (Precise measurement)
Stick the auxiliary earth spikes S(P) and H(C) into the ground deeply. They should bealigned at an interval of 5-10m from the earthed equipment under test. Connect thegreen wire to the earthed equipment under test, the yellow wire to the auxiliary earth
spike S(P) and the red wire to the auxiliary earth spike H(C) from terminals E, S(P) andH(C) of the instrument in order.

Fig.12-4
Note:●Make sure to stick the auxiliary earth spikes in the moist part of the soil. Give enoughwater where the spikes have to be stuck into the dry, stony or sandy part of the earthso that it may become moist.
●In case of concrete, lay the auxiliary earth spike down and water it, or put a wet dust
cloth etc. on the spike when making measurement.

55

2W test (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, acommon earth of a commercial power supply and an earth terminal of a building, can beused with two-pole method.

Fig.12-5
Rx = Re – reRx: True earth resistance
Re: Indicated value
re: Earth resistance of earth electrode(5) If the "Live Circuit" warning is displayed on the LCD and/or the buzzer sounds, do
not press the test switch but disconnect the instrument from the circuit. Make thecircuit dead before proceeding.
(6) Press the test switch, the display will show the earth resistance of the circuit.
● If measurement is made with the probes twisted or in touch with each other, thereading of the instrument may be affected by induction. When connecting the probes,
make sure that they are separated.
● If earth resistance of auxiliary earth spikes is too large, it may result in inaccurate
measurement. Make sure to stick the auxiliary earth spike in the moist part of the soil,
and ensure sufficient connections between the respective connections. High auxiliary
earth resistance may exist if "RS Hi" or "RH Hi" is displayed during measurements.
("Rs Hi" is displayed only when you press the test button to start a measurement.
It won't appear if any incidents, such as auxiliary earth spikes are disconnected,
happen during a measurement,)● When an earth voltage of 10V or higher (400Hz: 3V) exists, measured earth
resistances may include large errors. In this case, power off the devices which isusing earth resistance under test to reduce the earth voltages.

5613. Phase rotation tests
1. Press the Power switch and turn on the instrument. Turn the rotary switch and selectthe PHASE ROTAION function.
2. Insert the test leads into the instrument. (Fig.13-1)
L1

RED

L2

L3

GREEN

BLUE

Fig.13-1

3. Connect each test leads to a circuit. (Fig.13-2)

Fig.13-2
4. Results are displayed as follows.
Phase sequence (Counter-clockwise)

Phase sequence (Clockwise)

Fig. 13-3 Correct phase sequenceFig.13-4 Reversed phase sequence

Voltage across the terminals andFrequency of L1-L2 voltage● When a message "No 3-phase system" or "---" is displayed, the circuit may not be a
3-phase system or a wrong connection may have been made. Check the circuit andthe connection.
● Presence of harmonics in measurement voltages, such as an inverter power supply,
may influence the measured results.

5714. Volts(1) Press the Power switch and turn on the instrument. Turn the rotary switch and selectthe VOLTS function.
(2) Insert the test leads into the instrument. (Fig.14-1)
L1

L2

L3
or

RED

GREEN

BLUE
Fig.14-1(3) Voltage value and frequency will be displayed on the LCD when applying AC voltage.
Note : A message "DC V" may be displayed when measuring AC voltages withfrequencies out of the range 45Hz - 65Hz.

Voltage between L-PE
Voltagefrequency
between L-PE

Voltages
between L-N
and N-PE
Fig.14-2

15. Touch pad(1) The touch pad measures the potential between the operator and the tester's PE terminal.
A message "PE HiV" is displayed on the LCD with the audible buzzer if a potential
difference of 100V or more is present between the operator and the PE terminal at
touching the Touch pad.
(2) Touch Pad function can be enabled and disabled (ON / OFF).
See "6. Setup mode" in this manual and select ON or OFF. In case that OFF isselected, a warning for "PE HiV" does
not appear and the buzzer does not sound.
* Initial setting: ON
Note : A message "PE HI V" may be displayed when testing inverters or measuring
voltages containing high frequencies even if a user isn't touching with the Touch Pad.

5816. Memory function
Measured result at each function can be saved in the memory of the instrument.
(MAX: 1000)
16.1 How to save the data
Save the result according to following sequence.
(Press ESC switch during the process to one step back.)(1) When measurement is done, press MEM switch
to enter the save mode. (Fig. 16-2)

Fig.16-1(2) Make setting for following items.
1. CIRCUIT No
2. BOARD No
3. SITE No
4. DATA No
Fig.16-2
Data is saved.

● Press the F1(▲) or F2(▼) switch to choose theparameter to change.
CIRCUIT No → BOARD No → SITE No → DATA No → CIRCUIT No …
● Press ENTER switch to select the parameter to be changed.
● Use F1(▲) or F2(▼) to alter the value of the parameter and confirm with ENTER
switch. The selectable range is shown in the table below.
CIECUIT No.
BOARD No.
SITE No.
DATA No.

0-99
0-99
0-99
0-999

(3) A press of F4 or MEM switch saves the measured data.
Note: Pressing ESC switch can one step back.

5916.2 Recall the saved data
Save data can be displayed on the LCD according to the following sequence.
(Pressing ESC switch during the adjustment can one step back.)(1) Hold down MEM switch 1 sec in stand-bymode enters RECALL mode and the LCD
shows a list of the save data. (Fig. 16-3)

Fig.16-3(2) Press ▲(F1) or ▼(F2) switch and selectthe data you wish to review, and then press
ENTER. (Fig. 16-4)

Fig.16-4(3) The selected data will be displayed. (Fig. 16-5)

Fig.16-5(4) Press F4 (EDIT) switch to edit the parameters that have been set at saving.
The LCD display will be as follows. Change the parameters - procedures are thesame as the saving data – and overwrite and save again; however, DATA No. is
unchangeable.

Fig.16-6

60

16.3 Delete the saved data
(1) To delete the saved data:
Press F3 switch in the state as Fig. 16-5 shows to delete data.
Confirmation message appears as shown below.
Press F3 switch to delete data.

Fig.16-7(2) To delete whole data:
Press F4 switch in the state as Fig. 16-4 shows to delete all data.
Confirmation message appears as shown below.
Press F4 switch to delete all data.

Fig.16-8

61

17 Transfer the stored data to PC
The stored data can be transferred to PC via Optical Adapter Model 8212USB

Fig.17-1●How to transfer the data:(1) Connect Model 8212USB to the USB Portof a PC. (Special driver for Model 8212USB
should be installed. See the instruction
manual for Model 8212USB for further
details.)(2) Insert Model 8212USB into the KEW
6516/6516BT as shown in Fig 17-2. Test
leads should be removed from the KEW
6516/ 6516BT at this time.
(3) Power on the KEW 6516/ 6516BT. (Anyfunction is OK.)
(4) Start special software "KEW Report" on
Fig.17-2
your PC and set the communication port.
Then click "Download" command, and thedata in the KEW 6516/ 6516BT will be transferred to your PC. Please refer to the
instruction manual of Model 8212USB and HELP of KEW Report for further details.
Note: Use "KEW Report" version 2.80 or later.
The latest "KEW Report" can be downloaded from our web site.

62

18. Bluetooth communication (KEW 6516BT only)
18.1 Bluetooth communication
KEW 6516BT has a Bluetooth communication function and can exchange data with
Android/ iOS tablet devices. (Not available on KEW 6516.)
Before starting to use this function, download the special application "KEW Smart *" via
the internet.
Some functions are available only while connected to the internet. For further detail,please refer to "18.2 KEW Smart *".
# WARNING
Radio waves at Bluetooth communication may affect the operations of medical
electronic devices. Special care should be taken when using Bluetooth connection in
the areas where such devices are present.
Cautions:● Using the instrument or tablet devices near wireless LAN devices (IEEE802.11.b/g)
may cause radio interferences, lowering of communication speed, resulting insignificant time lag in the display update rate between the instrument and tablet
device. In this case, keep the instrument and the tablet device away from thewireless LAN devices, or turn off the wireless LAN devices, or shorten the distance
between the instrument and the tablet device.
● It may be difficult to establish communication connection if either the instrument ortablet device is in a metal box. In such a case, change the measurement location or
remove the metal obstacle between the instrument and the tablet device.
● If any leaking of data or information occurs while making a communication using
Bluetooth function, we assume no responsibility for any released content.
● Some tablet devices, even if the application runs properly, may fail to establish
communication with the instrument. Please use another tablet device and try tocommunicate with. If you still cannot confirm the connection, there may be someproblem with the instrument unit. 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 Map are the trademark or registeredtrademark 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.

63

18.2 KEW Smart *The special application "KEW Smart *" is available on download site for free. (AnInternet access is required.) Please note that communication charge is incurred
separately for downloading applications and using special features of them. For yourinformation, "KEW Smart *" is provided on-line only.
Features of KEW Smart *:● Remote monitoring/ checking● Data save/ recall function● Map display
Measured locations can be checked on the Google Map 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 the site on Google
Play Store or App Store.

19. Auto-power-off
This instrument has auto-power-off function.
When the instrument is inactive for about 10 minutes, it turns off automatically.
Auto-power-off function doesn't work during a measurement, while applying voltage, andBluetooth communication (KEW 6516BT only) is being performed.
If there's no key operation for 2 min, backlight will dim automatically. Pressing any key
restores the brightness.

6420. Battery and fuse replacement# DANGER● Do not open the battery compartment cover if the instrument is wet.
● Do not replace batteries nor fuse during a measurement. To avoid getting electricalshock, power off the instrument and disconnect all test leads before replacing
batteries or fuse.
● The battery compartment cover must be closed and screwed before making
measurement.
20.1 Battery replacement
Replace batteries with new ones when the battery indicator shows "is almost empty.

"; battery level# CAUTION●Do not mix new and old batteries nor different types of batteries.
●Install batteries in correct polarity as marked inside.
(1) Power off the instrument and disconnect all test leads from the terminals.
(2) Unscrew two screws and remove the battery compartment cover. (Fig. 20-1)(3) Replace all eight batteries with new ones at once. Observe correct polarity wheninserting new batteries, Battery: Size AA Alkaline battery (LR6) x 8 pcs.
(4) Attach the battery compartment cover, and secure it with the two screws,
Note:
Clock setting will be cleared if no batteries were inserted in the instrument 10 min. or
longer. When battery replacement is required, be careful not to exceed this period. If theclock setting is cleared and restored to the default, please do the setting again.
20.2 Fuse replacement
The continuity test circuit is protected by a 600V 0.5A HRC ceramic type fuse situated in
the battery compartment, together with a spare.
Fuse : F 0.5A 600V (Φ6.3 x 32mm)
SIBA 7009463.0,5● Procedures(1) If the instrument fails to operate in the continuity test mode, first disconnect the test
leads from the instrument.
(2) Unscrew two screws and remove the battery compartment cover. (Fig. 20-1)(3) Take out the fuse and check for continuity with another continuity tester. If the fusehas blown, replace it with the spare fuse.
(4) Attach the battery compartment cover, and secure it with the two screws.

65Screw

-

+
-

+

+

Spare Fuse

-

+

Fuse
Fig.20-1

21. Servicing
If this tester should fail to operate correctly, return it to your distributor stating the exact
nature of the fault. Before returning the instrument ensure that:(1) The leads have been checked for continuity and signs of damage.
(2) The continuity mode fuse (situated in the battery compartment) has been checked.
(3) The batteries are in good condition.
Please remember to give all the information possible concerning the nature of thefault, as this will mean that the instrument will be serviced and returned to you
more quickly.

6622. Case and strap assembly
Attach the strap belt according to the following procedures. By hanging the instrument
around the neck, both hands will be left free for testing.

(1) Attach the Buckle to the KEW 6516/6516BT as shown in Fig.22-1.
Match the hole of the Buckle and the protrusion
at the side face of KEW 6516/6516BT and slide
it upwards.
Fig. 22-1(2) How to attach the shoulder pad:
Lead the shoulder pad through thestrap belt.
Fig. 22-2(3) How to install the strap belt:(4) How to fasten the strap belt:

Fig. 22-3

Fig. 22-4

Pass the strap belt down throughthe buckle from the top, and up.

Pass the strap through the buckle,
adjust the strap for length and secure.

67

CONTENTS
1. Safe testing................................................................................................................. 1
2. Instrument layout ........................................................................................................ 3
3. Accessories ................................................................................................................ 5
4. Features ..................................................................................................................... 7
5. Specification ............................................................................................................... 9
5.1 Measurement specification ................................................................................... 9
5.2 General specification .......................................................................................... 14
5.3 Applied standards ............................................................................................... 15
5.4 Operating uncertainty ......................................................................................... 16
5.5 Symbols and marks displayed on the LCD......................................................... 18
6. Setup mode .............................................................................................................. 19
7. Getting started .......................................................................................................... 20
7.1 Attaching metal tip/ adapter for test leads .......................................................... 20
7.2 Battery voltage check ......................................................................................... 21
7.3 Clock adjustment ................................................................................................ 21
7.4 Help function....................................................................................................... 22
8. Continuity (resistance) tests ..................................................................................... 23
8.1 Test procedure .................................................................................................... 23
8.2 2Ω Buzzer () function.................................................................................. 25

8.3 Switching test currents ....................................................................................... 25
8.4 Pat function......................................................................................................... 25
9. Insulation tests.......................................................................................................... 27
9.1 Measurement method......................................................................................... 28
9.2 Continuous measurement (Insulation resistance measurement) ....................... 30
9.3 Voltage characteristics of measurement terminals ............................................. 30
9.4 DAR/ PI measurement, 1-min value display ....................................................... 31
9.5 Pat function......................................................................................................... 31
9.6 SPD(Varistor) test ............................................................................................... 32
10. LOOP/ PSC/PFC ..................................................................................................... 33
10.1 Principles of measurement ............................................................................... 33
10.2 Measurement method for LOOP high current .................................................. 38
10.3 Measurement method for LOOP ATT (Anti trip technology) ............................. 42
10.4 Loop limit value................................................................................................. 46

DISTRIBUTORINSTRUCTION MANUAL

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

MULTI-FUNCTION TESTERKEW 6516 / 6516BT
11-2192-2385C