AEMC Instruments 6422, 6422 Kit-150 ft, 6424 Kit-150 ft, 6424, 6424 Kit-300 ft User manual

ENGLISH

■

GROUND TESTER

6422
6424

Find Quality Products Online at: [e-mail]

User Manual

www.GlobalTestSupply.com

Statement of Compliance

Chauvin Arnoux®, Inc. d.b.a. AEMC® Instruments
certifies that this instrument has been calibrated using
standards and instruments traceable to international
standards.

We guarantee that at the time of shipping your
instrument has met its published specifications.

An N.I.S.T. traceable certificate may be requested at
the time of purchase, or obtained by returning the
instrument to our repair and calibration facility, for a
nominal charge.

The recommended calibration interval for this
instrument is 12 months and begins on the date of
receipt by the customer. For recalibration, please use
our calibration services. Refer to our repair and

calibration section at

Serial #:

Catalog #:

Model #: 6422 / 6424

Please fill in the appropriate date as indicated:

Date Received:

Date Calibration Due:

Chauvin Arnoux®, Inc.

d.b.a AEMC

®

Instruments

2 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

CONTENTS

1. INTRODUCTION .................................................................................. 8

1.1. Battery Installation ......................................................................... 8

1.2. Battery Charging (Model 6424) .................................................... 10

1.3. Desktop Stand ............................................................................. 11

1.4. Instrument Interface ..................................................................... 11

1.5. Instrument Functions ................................................................... 13

1.6. Buttons and Keys ......................................................................... 13

1.7. LCD Display ................................................................................. 15

2. OPERATION ............................................................................... 16

2.1. Voltage Measurement .................................................................. 16

2.2. Resistance Measurement (2P) .................................................... 17

2.3. Grounding Resistance Measurement (3P) ................................... 20

2.4. AC Current Measurement (Model 6424) ...................................... 30

3. SPECIFICATIONS ...................................................................... 32

3.1. General Reference Conditions ..................................................... 32

3.2. Electrical Specifications ............................................................... 32

3.3. Influences ..................................................................................... 24

3.4. Uncertainty ................................................................................... 36

3.5. Environmental Conditions ............................................................ 37

3.6. Power Supply ............................................................................... 37

3.7. Mechanical S

3.8. International Standards ................................................................ 38

3.9. Electromagnetic Compatibility (CEM) .......................................... 38

4. MAINTENANCE ......................................................................... 39

4.1. Cleaning ....................................................................................... 39

4.2. Replacing the batteries ................................................................ 39

REPAIR AND CALIBRATION .............................................................. 40

TECHNICAL AND SALES ASSISTANCE ............................................. 40

LIMITED WARRANTY ........................................................................ 41

pecifications ............................................................ 38

Ground Tester Models 6422/6424 3

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

Thank you for purchasing the AEMC Ground Tester Model 6422 or 6424. For
best results from your instrument and for your safety, read the enclosed
operating instructions carefully and comply with the precautions for use. These
products must be only used by qualified and trained users.

WARNING, risk of DANGER! The operator must refer to these
instructions whenever this danger symbol appears.

CAUTION! Risk of electric shock. The voltage at the parts marked
with this symbol may be dangerous.

Useful information or tip.

Earth/ground.

Current clamp.

The product is declared recyclable following a life cycle analysis in
accordance with standard ISO 14040.

Battery.

Guarantees conformity with European directives and with
regulations covering EMC.

In the European Union, the product must undergo selective disposal
for the recycling of electric and electronic material, in compliance with
Directive WEEE 2002/96/EC.

4 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

Precautions

This instrument is compliant with safety standard IEC 61010-2-030 for voltages
up to 600V in category IV. Do not use the instrument for measurements on
circuits that are not in measurement categories II, III, or IV or that might be
connected inadvertently to circuits that are not in measurement categories II, III,
or IV.

 The operator and/or the responsible authority must carefully read and

clearly understand the various precautions to be taken in use. Sound
knowledge and a keen awareness of electrical hazards are essential
when using this instrument.

 If you use this instrument other than as specified, the protection it

provides may be compromised, thereby endangering you.

 Do not use the instrument on networks of which the voltage or category

exceeds those mentioned.

 Do not use the instrument if it seems to be damaged, incomplete, or

poorly closed.

 Before each use, check the condition of the insulation on the leads,

housing, and accessories. Any item of which the insulation is
deteriorated (even partially) must be set aside for repair or scrapping.

 Before using your instrument, check that it is perfectly dry. If it is wet, it

must be thoroughly dried before it can be connected or used.

 The use of leads (or accessories) of a lower voltage or category limits the

voltage or category of the combined instrument and leads (or
accessories) to that of the leads (or accessories).

 Use personal protection equipment systematically.
 When handling the leads, test probes, and alligator clips, keep your

fingers behind the physical guard.

 All troubleshooting and metrological checks must be performed by

competent and accredited personnel.

Definition of Measurement Categories (CAT)

CAT IV Measurement category IV corresponds to measurements taken at the

source of low-voltage installations.
Example: power feeders, counters and protection devices.

CAT III Measurement category III corresponds to measurements on building

installations.
Example: distribution panel, circuit-breakers, machines or fixed
industrial devices.

CAT II Measurement category II corresponds to measurements taken

on circuits directly connected to low-voltage installations.
Example: power supply to domestic electrical appliances and
portable tools.

Ground Tester Models 6422/6424 5

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

Receiving Your Shipment

Upon receiving your shipment, make sure that the contents are consistent with
the packing list. Notify your distributor of any missing items. If the equipment
appears to be damaged, file a claim immediately with the carrier and notify your
distributor at once, giving a detailed description of any damage. Save the
damaged packing container to substantiate your claim.

Ordering Information

Ground Tester Model 6422…………………..…….……............... Cat. #2135.55

Includes 6 AA alkaline batteries, carrying bag and user manual

Ground Tester Model 6422 Kit-150 ft …………………..….......... Cat. #2135.56

Includes ground tester, two 150 ft color-coded leads on spools (red/blue),
one 30 ft lead (green), two T-shaped auxiliary ground electrodes, set of two
5 ft color-coded (red/blue) leads, one 100 ft AEMC® tape measure, 6 AA
batteries, carrying bag and user manual

Ground Tester Model 6424…………………..…….……............... Cat. #2135.57

Includes 6 AA rechargeable NiMH batteries, USB to wall charger, 5V, 2A,
USB charger cable, carrying bag and user manual

Ground Tester Model 6424 Kit-150 ft …………………..….......... Cat. #2135.58

Includes ground tester, two 150 ft color-coded leads on spools (red/blue), one
30 ft lead (green), two T-shaped auxiliary ground electrodes, set of two 5 ft
color-coded (red/blue) leads, one 100 ft AEMC
rechargeable NiMH batteries, USB to wall charger, 5V, 2A, USB charger
cable, carrying bag and user manual

®

tape measure, 6 AA

Ground Tester Model 6424 Kit-300 ft …………………..….......... Cat. #2135.59

Includes ground tester, two 300 ft color-coded leads on spools (red/blue), two
100 ft color-coded leads (hand-tied, green/black), four T-shaped auxiliary
ground electrodes, set of two 5 ft color-coded (red/blue) leads, one 100 ft

®

AEMC
charger, 5V, 2A, USB charger cable, carrying bag and user manual

tape measure, 6 AA rechargeable NiMH batteries, USB to wall

Accessories

Ground Rod – Set of 2, 17” stainless steel T-shaped

auxiliary rods ………………..……………………………….......... Cat. #2135.44

AC Current Probe Model MN72 for use with Model 6424 only... Cat. #2153.06
Calibration checker for ground tester models 6422/6424…….… Cat.

#5000.92

6 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

Replacement Parts

Bag – Multi-purpose large canvas bag

(replacement for ground kits) …………..………..…….….......... Cat. #2119.82

Case – Replacement carrying case for Models 3620, 3640,
4600, 4610, AN1, 6422, 6424, 6501 & 6503…………….……... Cat. #2126.71

Tape measure – AEMC

Test Kit for 3-Point Testing ………………………………….…..… Cat. #2135.35

Includes two 150 ft color-coded leads on spools (red/blue), one 30 ft lead
(green), two T-shaped auxiliary ground electrodes, set of two 5 ft color­coded (red/blue) leads, one 100 ft AEMC

Ground Rod – Set of 2, 14.5” T-shaped auxiliary rods …..…..… Cat. #2135.39

Cable – Replacement USB charger cable w/wall plug
for Model 6424 ……………………………………………….…..… Cat. #2135.93

®

100 ft ………………………….……..… Cat. #2130.60

®

tape measure, and carrying bag

Ground Tester Models 6422/6424 7

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

1. INTRODUCTION

1.1 Battery Installation

1. Open the battery compartment cover.

2. With your fingers on either side of the cover, insert a tool (for example a
screwdriver) in the latching system, and lift up.

3. Remove the battery compartment cover.

8 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

4. Pull open the rubber seal covering the battery compartment.

5. Insert the batteries, ensuring correct polarities. We recommend
disposable batteries for the Model 6422 (for example alkaline) and
rechargeable batteries for the Model 6424. The Model 6422 comes with
alkaline batteries installed, and the Model 6424 with rechargeable
batteries installed.

6. Press the rubber seal back in place, ensuring it correctly covers the
compartment.

7. Replace the battery compartment cover.

If you insert disposable batteries in the Model 6424, the batteries will
last longer but the battery level indicator will be inaccurate.

If you insert rechargeable batteries in the Model 6422, the battery level
indicator will always display low battery level and the batteries
will not last as long.

Ground Tester Models 6422/6424 9

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

1.2 Battery Charging (Model 6424)

Before using the Model 6424 for the first time, you should fully charge the
battery. Charging must be done in a location with the temperature between 32
and 104°F (0 and 40°C).

Do not perform the charging procedure if disposable batteries are
installed in the instrument.

1. Connect one end of the provided USB cable to the Model 6424 terminal
block and the other end to a wall outlet using the provided external­power-to-USB adapter.

2. The instrument displays CHrG. While the battery charges, the battery
level indicator displays progress. Full charging requires approximately 6
hours.

3. When the battery level indicator shows full charge disconnect the
USB cable from the instrument.

10 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

1.3 Desktop Stand

Terminal block:

Hazardous

Backlit LCD display

TEST button

ON/OFF button

The instrument is equipped with two back supports that enable desktop operation
from an angled position. Pull the supports out to lock them in place, then place
the instrument on a flat surface.

1.4 Instrument Interface

1.4.1 Model 6422

3 measurement
terminals

voltage indicator

Ground Tester Models 6422/6424 11

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

1.4.2 Model 6424

Terminal block

Battery charger
input

MN72 AC Current Probe

Measurement terminals

Backlit LCD display

ON/OFF button

Function keys

TEST button

Connector for optional

Hazardous voltage indicator

Measurement data storage location

12 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

1.5 Instrument Functions

























terminals to C, P, X (§2.3.2).

The Models 6422 and 6424 are battery-powered portable measuring instruments
with LCD displays.

These instruments check the safety of electrical installations. They can be used
to test a new installation before it is powered up. They can also check an existing
installation (after it has been disconnected) or diagnose a malfunction in an
installation.

Function 6422 6424

Ground resistance measurement (with three rods)

Voltage measurement

Resistance measurement

Average of ground measurements at 52, 62, and 72%

RH over limit detection

RE over limit detection

Stray or foreign voltage on USE detection

AC current measurement with current clamp
(optional)

 

 

1.6 Buttons and Keys

Both models:

Buttons Function

Long press (>2 seconds) turns instrument ON.
Second long press turns instrument OFF.

Short press starts ground measurements in automatic mode
(§2.3.3).

Long press starts ground measurements in permanent mode.

TEST

+ TEST

Pressing TEST during a measurement stops the
measurement (§2.3.5).

At the end of the measurement, pressing TEST exits the frozen
measurement display.

Pressing and TEST simultaneously for >5 seconds while
turning ON the instrument changes the names of the H, S, E

Ground Tester Models 6422/6424 13

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

Model 6424 only:

Ke ys Function

V/A takes voltage measurements (§2.1), or current

V/A

Ω

measurements if a current probe is connected (§2.4).

In the latter case, a second press forces voltage
measurements.

Ω takes resistance measurements (§2.2).

Ω and TEST pressed simultaneously takes ground resistance

measurements (§2.3).

stores the displayed measurement with the S rod at 52%

of the distance (§2.3.4).

52%

0

62%

Pressing and then activates/deactivates lead
compensation.

Pressing and then for >2 seconds compensates the
resistance of the leads for the resistance measurement
(§2.2.2).

stores the displayed measurement with the S rod at 62%

of the distance (§2.3).

Pressing and then turns on backlighting for one
minute, or turns backlighting off.

stores the displayed measurement with the S rod at 72%

72%

CLR

of the distance (§2.3.4).

Pressing and then deactivates the Auto Off feature.

activates the “second” functions of the 52%, 62%, and

72% keys (§2.3).

Pressing for >2 seconds erases the values stored in
memory.

14 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

1.7 LCD Display

1. Battery level indicator
Auto Off enabled/disabled
lead compensation

2. Input terminals

3. In a 3P ground measurement:

HOLD indicates measurement is frozen
AVG indicates the displayed measurement is the average of 3

measurements
% indicates the range of variation in the averaged measurements

4. Main display

5. Errors in the displayed measurement and (Model 6424) in the ground
measurement stored in memory

6. (Model 6424) additional information about the ground measurement

Ground Tester Models 6422/6424 15

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2. OPERATION

2.1 Voltage Measurement (Model 6424)

The Model 6424 measures the RMS (Root Mean Square) voltage up to 600VAC.

1. Turn ON the instrument by pressing for >2 seconds.

2. Press to access the voltage measurement mode. The

symbol V appears on the right side of the LCD.

3. Connect one end of the leads to the V and COM terminals and the other
end to the sample under test.

The measurement appears on the LCD.

If the measurement falls outside the instrument’s measurement range,
the LCD displays >700.0V.

16 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2.2 Resistance Measurement (2P)

2.2.1 Model 6422

The sample under test should not be live.

1. Turn ON the instrument by pressing for >2 seconds. The
symbol 2P appears on the right side of the LCD.

2. Connect one end of the leads to the Ω and COM terminals and the other

end to the sample under test.

The measurement appears on the LCD.

Ground Tester Models 6422/6424 17

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2.2.2 Model 6424

If the message Err appears, the compensation procedure failed, either

The sample under test should be de-energized.

1. Turn ON the instrument by pressing for >2 seconds. The
symbol 2P appears on the right side of the LCD.

2. If the Model 6424 is already ON but in voltage or current

measurement mode, press to access the resistance
measurement mode.

3. Before making measurements, perform lead compensation. This
subtracts the test lead resistance from the measurement. Connect one
end of the leads to the Ω and COM terminals and touch the other ends
together, creating a short-circuit.

4. Press the button.

5. Press for >2 seconds. The symbol blinks during the
compensation procedure. When finished, the LCD displays

00.00Ω.

because the value to be compensated exceeds 5Ω or because the

leads were disconnected during compensation.

Press to deactivate/reactivate lead compensation.

18 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

6. Connect one end of the leads to the Ω and COM terminals and the other

end to the sample under test.

The measurement appears on the LCD.

The instrument displays the measured value minus the compensation.
The value displayed may be negative if the leads used for the
measurement are not the ones that were compensated. In this case,
repeat the compensation. Lead compensation is preserved after Auto
Off but not after the instrument is manually turned OFF.

Error messages:

>99.99kΩ: The measured value falls outside the instrument’s
measurement range.

NOISE: A stray or foreign voltage UHE > 3V is detected between the Ω
and COM terminals.

: A stray or foreign voltage U

and COM terminals; in this case measurement is not possible.

Note that 2P mode is useful for ensuring the H electrode connection is intact.

HE > 50V is detected between the Ω

Ground Tester Models 6422/6424 19

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2.3 Grounding Resistance (3P)

This function performs a 3-pole (3P) test to measure grounding resistance when
the electrical installation to be tested is de-energized (for example a new
installation). It uses two auxiliary rods, with the third rod being the grounding
electrode to be tested (hence the name 3P or 3-pole). To perform a 3P test, the
instrument:

1. Generates a 128Hz square wave between the H and E terminals, with
an amplitude of 10V peak. If the measurement is unstable, the test

frequency will automatically switch from 128Hz to 256Hz to improve the
measurement.

2. Measures the resulting current IHE along with the voltage between the S

and E terminals USE.

3. Calculates the value of RE = U

The 3P test can also be performed on an existing electrical installation, but the
power must be OFF. Whether testing a new or existing installation, the grounding
electrode system under test must be isolated from other grounding connections
during the measurement.

2.3.1 3-Point Test Theory of Operation

3-Point measurement is used to measure resistance to ground of auxiliary
ground electrodes and grids. The potential difference between rods E and S is
measured by a voltmeter, and the current flow between rods E and H is
measured by an ammeter.

By Ohm’s Law E = RI or R = E/I, we may obtain the ground electrode resistance
R.

SE

/ IHE.

If E = 20V and I = 1A, then:

20

E

=

I

= 20 ohms

1

R=

It is not necessary to calculate all the measurements when using a ground tester.
The ground tester will measure directly by generating its own current and
displaying the resistance of the ground electrode.

20 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2.3.1.1 Position of the Auxiliary Electrodes in Measurements

The goal in precisely measuring the resistance to ground is to place the auxiliary
current electrode H far enough from the ground electrode under test so that the
auxiliary potential electrode S will be outside of the effective resistance areas of
both the ground electrode and the auxiliary current electrode. The best way to
find out if the auxiliary potential rod S is outside the effective resistance areas is
to move it between E and H and to take a reading at each location. If the auxiliary
potential rod S is in an effective resistance area (or in both if they overlap), by
displacing it, the readings taken will vary noticeably in value. Under these
conditions, no exact value for the resistance to ground may be determined.

On the other hand, if the auxiliary potential rod S is located outside the effective
resistance areas, as S is moved back and forth the reading variation is minimal.
The readings taken should be relatively close to each other, and are the best
values for the resistance to ground of the ground E. The readings should be
plotted to ensure that they lie in a “plateau” region as shown below.

Ground Tester Models 6422/6424 21

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2.3.1.2 Measuring Resistance of Ground Electrodes (62% Method)

The 62% method the most accurate method but is limited by the fact that the
ground tested is a single unit. This method applies only when all three electrodes
are in a straight line and the ground is a single electrode, pipe, or plate, etc., as
shown below.

Consider the illustration below, which shows the effective resistance areas
(concentric shells) of the ground electrode E and of the auxiliary current
electrode H. The resistance areas overlap.

22 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

If readings were taken by moving the auxiliary potential electrode S towards
either E or H, the reading differentials would be great and we could not obtain a
reading within a reasonable band of tolerance. The sensitive areas overlap and
act constantly to increase resistance as S is moved away from E.

Now consider the illustration below, where the E and H electrodes are sufficiently
spaced so that the areas of effective resistance do not overlap. If we plot the
resistance, measured we find that the measurements level off when S is placed
at 62% of the distance from E to H, and that the readings on either side of the
initial Y setting are most likely to be within the established tolerance band. This
tolerance band is defined by the user and expressed as a percent of the initial
reading: ±2%, ±5%, ±10%, etc.

Ground Tester Models 6422/6424 23

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2.3.1.3 Auxiliary Electrode Spacing

No definite distance between X and Z can be given, since this distance is relative
to the diameter of the electrode tested, its length, the homogeneity of the soil
tested, and particularly, the effective resistance areas. However, an approximate
distance may be determined from the following chart which is given for a
homogeneous soil and an electrode of 1" in diameter. (For a diameter of 1/2",
reduce the distance by 10%; for a diameter of 2" increase the distance by 10%.)

24 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

Approximate Distance to Auxiliary Electrodes Using the 62% Method

6 ft

45 ft

72 ft

8 ft

50 ft

80 ft

12 ft

60 ft

96 ft

18 ft

71 ft

115 ft

20 ft

74 ft

120 ft

30 ft

86 ft

140 ft

Depth Driven Distance to Y Distance to Z

10 ft 55 ft 88 ft

2.3.1.4 Multiple Electrode System

A single driven ground electrode is an economical and simple means of making a
good ground system, but sometimes a single rod will not provide sufficient low
resistance, and several ground electrodes will be driven and connected in
parallel by a cable.

Very often when two, three or four ground electrodes are used, they are driven in
a straight line. When four or more are used, a hollow square configuration is
used and the ground electrodes are still connected in parallel and equally spaced
(see below).

Ground Tester Models 6422/6424 25

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

In multiple electrode systems, the 62% method electrode spacing may no longer

Max Grid Distance

Distance to Y

Distance to Z

6 ft

78 ft

125 ft

8 ft

87 ft

140 ft

10 ft

100 ft

160 ft

12 ft

105 ft

170 ft

14 ft

118 ft

190 ft

16 ft

124 ft

200 ft

18 ft

130 ft

210 ft

20 ft

136 ft

220 ft

30 ft

161 ft

260 ft

40 ft

186 ft

300 ft

50 ft

211 ft

340 ft

60 ft

230 ft

370 ft

80 ft

273 ft

440 ft

100 ft

310 ft

500 ft

120 ft

341 ft

550 ft

140 ft

372 ft

600 ft

160 ft

390 ft

630 ft

180 ft

434 ft

700 ft

200 ft

453 ft

730 ft

be applied directly. The distance of the auxiliary electrodes is now based on the
maximum grid distance (e.g. in a square, the diagonal; in a line, the total length).
A square having a side of 20 ft will have a diagonal of approximately 28 ft.

Multiple Electrode System

2.3.2 Terminals Definitions

By default, the instrument’s terminals are defined as H, S, and E. To change
these to C, P, and X:

While turning ON the instrument, simultaneously press and

hold down the and TEST buttons for >5 seconds. The
terminal assignments will be changed to C, P, and X. These
assignments will be retained even when the instrument is
turned OFF.

26 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2.3.3 Grounding Resistance Measurement

For the first grounding resistance test, we recommend starting with the 62%
distance.

1. Place the H and S rods in a line with the grounding electrode under test.
The distance between the S rod and the grounding electrode must be
approximately 62% of the distance (d) between the H rod and the
grounding electrode. (To avoid electromagnetic interference, we
recommend using the full length of the cables, placing them several
inches apart and avoiding loops.)

2. Connect the cables to the H and S terminals.

3. Power down the installation and isolate the ground under test from other
ground systems and connections.

4. Connect the E terminal to the grounding electrode to be tested.

5. Press TEST to take a measurement in automatic mode.

The TEST button blinks red, then the measurement is displayed. It
remains frozen (HOLD) until you press TEST again.

(Model 6424) R

and USE values are displayed.

H

Ground Tester Models 6422/6424 27

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2.3.4 Measurement Average (Model 6424)

After completing the measurement made with the S rod at 62% of the distance

between the H rod and the grounding electrode, press to store the value in
memory.

1. Place the S rod at 72% of the distance d and take another measurement.

2. Press to store the measurement.

3. Place the S rod at 52% of d, and take another measurement.

4. Press to store the measurement.

The instrument immediately calculates and displays the average of the
three measurements and the percent difference between the lowest and
highest values. For the measurement to be valid, the difference must not
exceed 5%. If it is, place the H electrode out further and repeat the tests
at the 52%, 62%, and 72% distances.

Press for >2 seconds to erase the stored measurements.

28 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2.3.5 Measurement Mode (Model 6424)

1. Place the H and S rods and connect the instrument as explained in

§2.3.2.

2. Press TEST for >2 seconds to start the measurement.

The TEST button blinks red, then the measurement is displayed.

(Model 6424) RH and USE values are displayed.

3. Press TEST to stop the measurement.

2.3.6 Validating the Measurement

1. Place S rod at 72% of d and take a measurement.

2. Move the S rod to 52% of d and take a measurement.

All three measurements must be within 5% of each other for the measurement to
be valid. If not, the S rod is within the zone of influence of the grounding
electrode. If this is the case, place the H electrode further away and repeat the
measurement.

Ground Tester Models 6422/6424 29

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2.3.6.1 Auxiliary Rod Positioning

To ensure measurements are not distorted by interference, we recommend
repeating the measurement with the auxiliary rods placed at a different distance
and in another direction (for example rotated 90° from the first alignment).

If the measurements match, they are valid. If they differ significantly, they could
be influenced by factors such as ground currents or a groundwater artery. In this
case, we recommend driving the auxiliary rods deeper into the ground.

If in-line rod configuration is not possible, you can place the rods in an equilateral
triangle. To validate the measurement, move the S rod on either side of the line
HE.

2.3.6.2 Ground Measurement Tips

 To avoid “cross-talk” with the measurement current, do not route the

connecting cables of the rods near or parallel to other cables
(transmission or power supply), metal pipes, rails, or fences.

 To reduce auxiliary rod resistance, add one or more rods, two meters

apart, in the H (S) circuit of the circuit.

 Another way to reduce rod resistance is to drive the rods deeper and

firmly pack the earth around them, or sprinkle water on them.

After completing the measurement, reconnect the grounding strip
before restoring power to the installation.

30 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

2.3.7 Error Messages

>3.000kΩ

RH ! (blinking)

(Model 6422) Measurement outside range

>60.00kΩ

S (blinking)
P (blinking)

NOISE

(Model 6424) Measurement outside range

S rod resistance >50kΩ

H rod resistance >15kΩ

or UHE voltage amplitude is between 3 and 50V

U

SE

(blinking)

USE or UHE > 50V (no measurement is possible)

2.4 AC Current Measurement (Model 6424)

AC current measurement requires an optional MN72 current probe.

1. Turn ON the instrument by pressing for >2 seconds.

2. Press .

3. Connect the clamp to the instrument’s current terminal (identified by the

symbol). The A and symbols appear on the LCD.

4. Open the clamp and place it on the conductor under test.

Ground Tester Models 6422/6424 31

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

The measurement appears on the LCD.

Error messages:
>70.00A: The measured value falls outside the instrument’s

measurement range.

Err: The probe is not completely inserted (the symbol also
blinks).

32 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

3. SPECIFICATIONS

Quantity of influence

Reference values

Model 6424: 6 ± 0.2 V

Frequency

45 to 65Hz

Electric field

< 0.1V/m

Magnetic field

< 40A/m

Resolution

0.1V

Intrinsic uncertainty

± (1% R + 1 ct)

3.1 General Reference Conditions

Temperature 73 ± 3.6 °F (23 ± 2 °C)

Relative humidity 45 to 75% RH

Supply voltage

Intrinsic uncertainty is the error defined under the reference conditions.

Operating uncertainty includes the intrinsic uncertainty plus the effects of

variation of the quantities of influence (supply voltage, temperature, interference,
etc.) as defined in standard IEC 61557-5.

The uncertainties are expressed in % of the reading (R) and in number of display
counts (ct): ± (a% R + b ct)

The Model 6424 cannot make measurements when the battery
charger is connected.

Model 6422: 8 ± 0.2 V

3.2 Electrical Specifications

3.2.1 Voltage Measurement

Additional reference condition:

Peak factor = √2

UHE Voltage Measurement

Measurement range 0.1 – 600.0V

Ground Tester Models 6422/6424 33

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

3.2.2 Resistance Measurement (2P)

range

uncertainty

voltage

range

Intrinsic
uncertainty

frequency

±10V

PEAK

Measurement
range

Resolution

0.01Ω

0.1Ω

1Ω

10Ω

uncertainty

Measurement
frequency

voltage

Additional reference conditions:

External voltage between H and E terminals = zero.
Resistance of the leads ≤ 0.1Ω.

Measurement

Resolution

Intrinsic

UHE no-load

0.05 - 99.99Ω 80.0 - 999.9Ω 0.800 - 9.999kΩ 8.00 - 50.00kΩ

0.01Ω 0.1Ω 1Ω 10Ω

± (2% R + 10 ct) ± (2% R + 2 ct) ± (2% R + 1 ct) ± (2% R + 1 ct)

±10V

PEAK

The compensation of the leads of the Model 6424 may result in a negative
reading of up to 5Ω.

3.2.3 Ground Resistance Measurement (3P)

Additional reference conditions:

Resistance of the E lead: ≤ 0.1Ω
R

(rod + lead) ≤ 100Ω

H

(rod + lead) ≤ 1kΩ

R

S

Spurious voltages on U

Model 6422 Ground Measurement

Measurement

Resolution

Measurement

and USE ≤ 0.01V

HE

0.50 - 99.99Ω 80.0 - 999.9Ω 0.800 – 2.000kΩ

0.01Ω 0.1Ω 1Ω

± (1% R + 10 ct) ± (1% R + 2 ct) ± (1% R + 1 ct)

128Hz or 256Hz

No-load voltage

Model 6424 Ground Measurement

0.50 - 99.99Ω 80.0 - 999.9Ω 0.800 - 9.999kΩ 8.00 - 50.00kΩ

Intrinsic

± (1% R + 10 ct) ± (1% R + 2 ct) ± (1% R + 1 ct) ± (1% R + 1 ct)

128Hz, or 256Hz if the spurious voltage is at 128Hz

No-load

±10V

PEAK

The measurement current is a square signal of not more than 20mA.

34 Ground Tester Models 6422/6424

www.GlobalTestSupply.com

Find Quality Products Online at: [e-mail]

RH Ground Electrode Resistance Measurement (Model 6424)

8.00 – 49.99kΩ

1Ω

10Ω

0.01V

0.1V

range

uncertainty

of use

Variation of the measurement

Typical

Maximum

Frequency

DC to 440Hz

-

-3dB

Peak factor

1.4 to 3 (up to 300V)

-

± 1% R

Measurement range

Resolution

Intrinsic uncertainty

Voltage Measurement (Model 6424)

U

SE

Measurement range

Resolution

Intrinsic uncertainty

The instrument is protected up to 600V between any two of the three input
terminals.

0.050 – 9.999kΩ

± (10% R + 1 ct) ± (10% R + 1 ct)

0.10 - 99.99V

± (2% R + 2 ct) ± (2% R + 2 ct)

80.0 - 600.0V

AC/DC

AC/DC

3.2.4 Current Measurement (Model 6424)

Additional reference condition:

Peak factor = √2

Measurement

0.5 - 999.9mA 0.800 - 9.999A 8.00 - 60.00A

Resolution

Intrinsic

0.1mA 1mA 10mA

± (1% R + 4 ct) ± (1% R + 2 ct) ± (1% R + 2 ct)

3.3 Influences

3.3.1 Voltage Measurement (Model 6424)

Quantities of influence

Temperature

Relative humidity 10 to 90% RH - ± 2% R

DC and 50/60Hz
common mode rejection

Limits of the range

14 to + 122 °F

(-10 to + 50 °C)

0 to 600VAC 65dB 50dB

± 0.2% R ± (0.5% R + 1 ct)

Ground Tester Models 6422/6424 35

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

3.3.2 Resistance Measurement (2P)

influence

of use

Variation of the measurement

Typical

Maximum

Relative humidity

10 to 90% RH

± 1% R

± 2% R

posed on

influence

of use

Variation of the measurement

Typical

Maximum

Relative humidity

10 to 90% RH

-

± 2% R

Rod resistance
RS

Quantities of

Temperature

Supply voltage

50/60Hz voltage
superim
the test voltage

Limits of the range

14 to + 122 °F

(-10 to + 50 °C)

Model 6422: 6.0 to 9.6V
Model 6424: 6.0 to 7.6V

0 to 3V

3 to 25V

3.3.3 Ground Measurement (3P)

Quantities of

Temperature

Supply voltage

Voltage in series
between S and
E, 50/60Hz

Limits of the range

14 to + 122 °F

(-10 to + 50 °C)

Model 6422: 6.0 to 9.6V
Model 6424: 6.0 to 7.6V

0 to 3V ± (0.5% R + 0.2Ω) ± (1% R + 1Ω)

3 to 25V ± (2% R + 8Ω) ± (4% R + 20Ω)

± (25 ppm R +

10mΩ/°C)

- ± (2% R + 1Ω)

± (0.5% R + 0.5Ω)

± (2% R + 5Ω)

± 1% R ± 2% R

- ± (2% R + 1Ω)

± (200 ppm R +

2 mΩ/°C)

± (2% R + 1Ω)

± (4% R + 10Ω)

Voltage in series
between H and
E, 50/60Hz

Rod resistance
R

H

0 to 3V ± (0.5% R + 0.2Ω) ± (1% R + 1Ω)

3 to 25V ± (20% R + 10Ω) ± (30% R + 20Ω)

0 to 50 kΩ - ± (2% R + 1Ω)

< 100 x R

R

H

and RH < 50kΩ

E

± (2% R + 2 ct) ± (10% R + 5 ct)

36 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

3.3.4 Current Measurement (Model 6424)

influence

of use

Variation of the measurement

Typical

Maximum

Relative humidity

10 to 90% RH

± 0% R

± 1% R

Quantities of

Temperature

Limits of the range

14 to + 122 °F

(-10 to + 50 °C)

± 250 ppm R ± 500 ppm R

Frequency DC to 440Hz - -3dB

Peak factor 1.4 to 3 (up to 30A) ± 0% R ± 1%

3.4 Uncertainty

The instruments comply with standard IEC-61557 part 5, which requires that the
operating uncertainty (B) be less than 30%.

In ground measurement:







= ± 󰇧||+ . 



+ 



+ 



+ 




+ 

with

A = intrinsic uncertainty
E1 = influence of the reference position ± 90°

E

= influence of the supply voltage within the limits indicated by the

2

manufacturer
E3 = influence of the temperature between 32 and 95°F (0 and 35°C)

E

= influence of the interference voltage in series mode (3V at 16.6; 50; 60

4

and 400Hz)
E5 = influence of the resistance of the rods from 0 to 100 x RA but ≤ 50kΩ

E

= influence of the network frequency from 99 to 101% of the nominal

7

frequency
E

= influence of the network voltage from 85 to 110% of the nominal voltage

8

The uncertainty of operation of the instrument is ≤ 15% + 1Ω




+ 




+ 



󰇨



Ground Tester Models 6422/6424 37

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

3.5 Environmental Conditions

Voltage /
Current

> 2500 measurements from 5s to

100Ω

> 2000 measurements from 5s to

100Ω

Ground test
(3P)

> 2000 measurements from

100Ω

Instrument off

> 1 year

> 1 year

1 = Reference range, 70 to 77°F (21 to 25°C)
2 = Operating range, 14 to 122°F (-10 to +50°C)
3 = Storage range (without batteries), -40 to +158°F (-40 to +70°C)

Range for recharging of the rechargeable batteries; 32 to 104°F (0 to 40°C)
Indoor and outdoor use
Altitude < 6500’ (2,000m)
Pollution degree 2

3.6 Power Supply

Model 6422: 6 LR6 or AA disposable batteries.

Model 6424: 6 NiMH type AA rechargeable batteries. The charging time is

approximately 6 hours.

During charging, the instrument cannot make measurements. All front
panel buttons are disabled.

Typical time between battery charges

Function

Resistance

Model 6422

(disposable batteries

> 80h > 50h

> 1500 measurements from 100Ω

Model 6424

(rechargeable batteries)

38 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

3.7 Mechanical Specifications

Dimensions (L x D x H): 8.78 x 4.96 x 2.75” (223 x 126 x 70mm)

Weight:

Protection class:

Free fall test:

approximately 2.2 lb (1kg)
IP 65 per IEC 60 529 IK 04

per IEC 50102

1 meter per IEC 61010-1

3.8 International Standards

The instrument:

 Conforms with IEC 61010-2-030, 600V CAT IV, pollution degree 2.

Assigned characteristics: measurement CAT IV, 600 V with respect to
earth.

 Complies with IEC 61557 parts 1 and 5.
 Is protected by reinforced insulation.

3.9 Electromagnetic Compatibility (CEM)

The instrument conforms with standard IEC 61326-1.

Ground Tester Models 6422/6424 39

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com

4. MAINTENANCE

Except for the batteries, the instrument contains no parts that can
be replaced by personnel who have not been specially trained and
accredited. Any unauthorized repair or replacement of a part by
an “equivalent” may severely impair safety.

4.1 Cleaning

Disconnect the instrument from all leads, probes, etc. and turn it OFF.

Use a soft cloth, dampened with soapy water. Rinse with a damp cloth and dry
rapidly with a dry cloth or forced air. Do not use alcohol, solvents, or
hydrocarbons.

4.2 Battery Replacement

1. Disconnect the instrument from all leads, probes, etc. and turn it OFF.

2. Open the battery compartment as instructed in §1.1.

3. Remove the old batteries.

4. Insert new batteries as instructed in §1.1.

Spent batteries must not be treated as ordinary household waste.
Take them to the appropriate recycling collection facility.

40 Ground Tester Models 6422/6424

Find Quality Products Online at: [e-mail]

www.GlobalTestSupply.com