AEMC instruments 6422 User manual

Ground Tester
Models 6422 & 6424
User Manual
ENGLISH
GROUND RESISTANCE TESTERS
WITH AEMC
®
INSTRUMENTS

Copyright©Chauvin Arnoux®, Inc. d.b.a. AEMC®Instruments. All rights reserved.
No part of this documentation may be reproduced in any form or by any means (including electronic
storage and retrieval or translation into any other language) without prior agreement and written consent
from Chauvin Arnoux®, Inc., as governed by United States and International copyright laws.
Chauvin Arnoux®, Inc. d.b.a. AEMC®Instruments
15 Faraday Drive • Dover, NH 03820 USA
Tel: [phone] or [phone] • Fax: [phone]
This documentation is provided “as is,” without warranty of any kind, express, implied, or otherwise.
Chauvin Arnoux®, Inc. has made every reasonable e󰀨ort to ensure that this documentation is accurate;
but does not warrant the accuracy or completeness of the text, graphics, or other information contained
in this documentation. Chauvin Arnoux®, Inc. shall not be liable for any damages, special, indirect,
incidental, or inconsequential; including (but not limited to) physical, emotional or monetary damages
due to lost revenues or lost prots that may result from the use of this documentation, whether or not the
user of the documentation has been advised of the possibility of such damages.

Statement of Compliance
Chauvin Arnoux®, Inc. d.b.a. AEMC® Instruments
certies 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 specications.
An NIST traceable certicate 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 www.aemc.com.
Serial #:
Catalog #:
Model #: 6422 / 6424
Please ll in the appropriate date as indicated:
Date Received:
Date Calibration Due:
Chauvin Arnoux®, Inc.
d.b.a AEMC®Instruments
www.aemc.com

TABLE OF CONTENTS
1. INTRODUCTION ..................................................................6
1.1 PRECAUTIONS FOR USE ........................................................ 7
1.2 RECEIVING YOUR SHIPMENT................................................ 7
1.3 ORDERING INFORMATION..................................................... 8
1.3.1 Accessories and Replacement Parts ................................. 9
1.4 BATTERY INSTALLATION ...................................................... 10
1.5 BATTERY CHARGING MODEL (6424)................................... 12
1.6 DESKTOP STAND ................................................................... 12
1.7 INSTRUMENT INTERFACE.................................................... 13
1.7.1 Model 6422........................................................................ 13
1.7.2 Model 6424 ....................................................................... 14
1.8 INSTRUMENT FUNCTIONS................................................... 15
1.9 BUTTONS AND KEYS............................................................. 15
1.10 L C D D I S P L AY ......................................................................... 17
2. OPER ATION ...................................................................... 18
2.1 VOLTAGE MEASUREMENT (MODEL 6424).......................... 18
2.2 RESISTANCE MEASUREMENT (2P) .................................... 19
2.2.1 Model 6422....................................................................... 19
2.2.2 Model 6424 ...................................................................... 20
2.3 GROUNDING RESISTANCE (3P) .......................................... 22
2.3.1 3-Point Test Theory of Operation ..................................... 22
2.3.1.1 Position of the Auxiliary Electrodes in Measurements ..... 23
2.3.1.2 Measuring Resistance of Ground Electrodes (62 %
Method).................................................................................... 24
2.3.1.3 Auxiliary Electrode Spacing ......................................... 25
2.3.1.4 Multiple Electrode System ........................................... 26
2.3.2 Terminals Denitions........................................................ 27
2.3.3 Grounding Resistance Measurement............................... 28
2.3.4 Measurement Average (Model 6424)............................... 29
2.3.5 Measurement Mode (Model 6424) ................................... 30
2.3.6 Validating the Measurement............................................. 30
2.3.6.1 Auxiliary Rod Positioning ............................................. 31
2.3.6.2 Ground Measurement Tips.......................................... 31
2.3.7 Error Messages ................................................................ 32
2.4 AC CURRENT MEASUREMENT (MODEL 6424).................. 32

3. SPECIFICATIONS .............................................................34
3.1 GENERAL REFERENCE CONDITIONS................................ 34
3.2 ELECTRICAL SPECIFICATIONS........................................... 34
3.2.1 Voltage Measurement (Model 6424) (V/A) ....................... 34
3.2.2 Resistance Measurement (2P)......................................... 35
3.2.3 Ground Resistance Measurement (3P)............................ 35
3.2.4 Current Measurement (Model 6424) ................................ 36
3.3 INFLUENCES........................................................................... 36
3.3.1 Voltage Measurement (Model 6424)................................. 36
3.3.2 Resistance Measurement (2P)......................................... 37
3.3.3 Resistance Measurement (3P)......................................... 37
3.3.4 Current Measurement (Model 6424) ................................ 38
3.4 UNCERTAINTY........................................................................ 38
3.5 ENVIRONMENTAL CONDITIONS ......................................... 39
3.6 POWER SUPPLY ..................................................................... 39
3.7 MECHANICAL SPECIFICATIONS ......................................... 40
3.8 INTERNATIONAL STANDARDS ............................................ 40
3.9 ELECTROMAGNETIC COMPATIBILITY (CEM) ................... 40
4. MAINTENANCE ................................................................ 41
4.1 CLEANING................................................................................ 41
4.2 BATTERY REPLACEMENT .................................................... 41
4.3 REPAIR AND CALIBRATION ................................................. 41
4.4 TECHNICAL ASSISTANCE .................................................... 42
4.5 LIMITED WARRANTY............................................................. 42
4.5.1 Warranty Repairs.............................................................. 43

6 Ground Resistance Testers Models 6422 & 6424
1. INTRODUCTION
Thank you for purchasing an AEMC®Instruments Ground Tester Model 6422 or
6424.
For the best results from your instrument and for your safety, you must read the
enclosed operating instructions carefully and comply with the precautions for use.
Only qualied and trained operators should use this product.
Symbols and Denitions
CAUTION - Risk of Danger! Indicates a WARNING. Whenever this symbol
is present, the operator must refer to the user manual before operation
CAUTION - Indicates a risk of electric shock. The voltage at the parts
marked with this symbol may be dangerous
Indicates important information to acknowledge
Ground/Earth
Current Clamp
The product has been declared recyclable
Battery
This product complies with the Low Voltage & Electromagnetic Compatibility
European directives (73/23/CEE & 89/336/CEE)
In the European Union, this product is subject to a separate collection
system for recycling electrical and electronic components in accordance with
directive WEEE 2002/96/EC
Denition of Measurement Categories (CAT)
CAT IV corresponds to measurements performed at the primary electrical supply
(< 1000 V).
Example: primary overcurrent protection devices, ripple control units, and
meters.
CAT III corresponds to measurements performed in the building installation at the
distribution level.
Example: hardwired equipment in xed installation and circuit breakers.
CAT II corresponds to measurements performed on circuits directly connected to
the electrical distribution system.
Example: measurements on household appliances and portable tools.

Ground Resistance Testers Models 6422 & 6424 7
1.1 PRECAUTIONS FOR USE
This instrument is compliant with safety standard IEC 61010-2-030 for voltages
up to 600 V 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 specied, 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 ngers
behind the physical guard.
All troubleshooting and metrological checks must be performed by
competent and accredited personnel.
1.2 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, le 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.

8 Ground Resistance Testers Models 6422 & 6424
1.3 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, (2) 150 ft color-coded leads on spools (red/blue), (1) 30 ft
lead (green), (2) T-shaped auxiliary ground electrodes, set of (2) 5 ft color-coded
(red/blue) leads, (1) 100 ft AEMC® Instruments 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, 5 V, 2 A,
USB charger cable, carrying bag and user manual
Ground Tester Model 6424 Kit-150 ft …………..…..……..…..........Cat. #2135.58
Includes ground tester, (2) 150 ft color-coded leads on spools (red/blue), (1) 30
ft lead (green), (2) T-shaped auxiliary ground electrodes, set of (2) 5 ft color-
coded (red/blue) leads, (1) 100 ft AEMC®Instruments tape measure, (6) AA
rechargeable NiMH batteries, USB to wall charger, 5 V, 2 A, USB charger cable,
carrying bag and user manual
Ground Tester Model 6424 Kit-300 ft …………..…………. ...........Cat. #2135.59
Includes ground tester, (2) 300 ft color-coded leads on spools (red/blue), (2)
100 ft color-coded leads (hand-tied, green/black), four T-shaped auxiliary
ground electrodes, set of (2) 5 ft color-coded (red/blue) leads, (1) 100 ft AEMC®
Instruments tape measure, (6) AA rechargeable NiMH batteries, USB to wall
charger, 5 V, 2 A, USB charger cable, carrying bag and user manual

Ground Resistance Testers Models 6422 & 6424 9
1.3.1 Accessories and Replacement Parts
Accessories
Ground Rod – Set of (2) 17 in stainless steel
T-shaped auxiliary rods …………………………………..……..............Cat. #2135.43
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
Replacement Parts
Bag – Multi-purpose large canvas bag
(replacement for ground kits) …………..……..……..…….….......... .... Cat. #2119.82
Case – Carrying case for Models 3620, 3640,
4600, 4610, AN1, 6422, 6424, 6501 & 6503…………….….……... ... Cat. #2126.71
Tape measure – AEMC®Instruments 100 ft …..……..….……..… ... Cat. #2130.60
Test Kit for 3-Point Testing …………………………….…….…..… .. Cat. #2135.35
Includes (2) 150 ft color-coded leads on spools (red/blue), (1) 30 ft lead (green),
(2) 14.5 in T-shaped auxiliary ground electrodes, set of (2) 5 ft color-coded (red/
blue) leads, (1) 100 ft AEMC® Instruments tape measure, and carrying bag
Test Kit for 3-Point Testing …………………………….…….…..… .. Cat. #2135.36
Includes (2) 300 ft color-coded leads on spools (red/blue), (2) 100 ft color-coded
leads (hand tied – green/black), set of (2) 5 ft color-coded (red/blue) leads, (4)
14.5 in T-shaped auxiliary ground electrodes, (1) set of (5) spaded lugs, (1) 100
ft AEMC® Instruments tape measure, and carrying bag
Ground Rod – Set of (2) 14.5 in T-shaped auxiliary rods…......... ... Cat. #2135.39
Cable – Replacement USB charger cable with wall plug
for Model 6424 ……………………………………………….….…..… .... Cat. #2135.93
Order Accessories and Replacement Parts Directly Online
Check our Storefront at www.aemc.com/store for availability

10 Ground Resistance Testers Models 6422 & 6424
1.4 BATTERY INSTALLATION
1. Open the battery compartment cover.
2. With your ngers 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.

Ground Resistance Testers Models 6422 & 6424 11
1. Pull open the rubber seal covering the battery compartment.
2. 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.
3. Press the rubber seal back in place, ensuring it correctly covers the
compartment.
4. Replace the battery compartment cover.
NOTE: 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.

12 Ground Resistance Testers Models 6422 & 6424
1.5 BATTERY CHARGING MODEL (6424)
Before using the Model 6424 for the rst 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).
NOTE: 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 external-power-
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.
1.6 DESKTOP STAND
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 at surface.

Ground Resistance Testers Models 6422 & 6424 13
1.7 INSTRUMENT INTERFACE
1.7.1 Model 6422

14 Ground Resistance Testers Models 6422 & 6424
1.7.2 Model 6424

Ground Resistance Testers Models 6422 & 6424 15
1.8 INSTRUMENT FUNCTIONS
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) 
✔
1.9 BUTTONS AND KEYS
Both Models:
Buttons Function
Long press (> 2 seconds) turns instrument ON.
Second long p ress turns instrument OFF.
TEST
Short press starts ground measurements in
automatic mode (§ 2.3.3).
Long press starts ground measurements in
permanent mode. Pressing TEST during a
measurement stops the measurement (§ 2.3.5).
At the end of the measurement, pressing TEST
exits the frozen measurement display.
. + TEST
Pressing and TEST simultaneously for
> 5 seconds while turning ON the instrument
changes the names of the H, S, E terminals to C,
P, X (§ 2.3.2).

16 Ground Resistance Testers Models 6422 & 6424
Model 6424 only:
Keys Function
V/A
V/A takes voltage measurements (§ 2.1), or
current measurements if a current probe is
connected (§ 2.4). In the latter case, a second
press forces voltage measurements.
Ω
Ωtakes resistance measurements (§ 2.2).
Ωand TEST pressed simultaneously takes
ground resistance measurements (§ 2.3).
52 %
stores the displayed measurement with the
S rod at 52 % of the distance (§ 2.3.4).
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).
62 % 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
o󰀨.
72 %
stores the displayed measurement with the
S rod at 72 % of the distance (§ 2.3.4).
Pressing and then deactivates the
Auto O󰀨 feature.
CLR
activates the “second” functions of the
52 %, 62 %, and 72 % keys (§ 2.3).
Pressing for > 2 seconds erases the
values stored in memory.

Ground Resistance Testers Models 6422 & 6424 17
1.10 LCD DISPLAY
1. Battery level indicator
Auto O󰀨 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

18 Ground Resistance Testers Models 6422 & 6424
2. OPERATION
2.1 VOLTAGE MEASUREMENT (MODEL 6424)
The Model 6424 measures the RMS (Root Mean Square) voltage up to 600 VAC.
1. Turn ON the instrument by pressing for > 2 seconds.
2. Press to access the voltage measurement mode. The
symbol Vappears on the right side of the LCD.
3. Connect one end of the leads to the Vand COM terminals and
the other end to the sample under test.
The measurement appears on the LCD.
NOTE: If the measurement falls outside the instrument’s
measurement range, the LCD displays > 700 V.

Ground Resistance Testers Models 6422 & 6424 19
2.2 RESISTANCE MEASUREMENT (2P)
2.2.1 Model 6422
NOTE: 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 Ωand COM terminals and
the other end to the sample under test.
The measurement appears on the LCD.

20 Ground Resistance Testers Models 6422 & 6424
2.2.2 Model 6424
NOTE: 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 Ωand 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 nished, the LCD displays 00.00Ω.
NOTE: If the message Err appears, the compensation procedure
failed, either because the value to be compensated exceeds 5 Ω or
because the leads were disconnected during compensation.
Press to deactivate/reactivate lead compensation.