Technical Data
Fluke 1623-2
and 1625-2
GEO Earth Ground Testers
The new Fluke 1623-2 and
1625-2 GEO Earth Ground
Testers offer data storage
and download capabilities
via USB port. World class
accessories will simplify
and speed up testing time.
Product features:
• 3- and 4-pole Fall of Potential,
earth resistance loop testing
• 4-pole Soil Resistivity testing
• Selective earth ground rod
testing using 1 clamp
• Stakeless earth ground rod
testing using 2 clamps
• IP56 rated for outdoor use
• Professional carrying case
• USB data storage and transfer
In addition, the Fluke 1625-2
offers these advanced features:
• Automatic Frequency Control
(AFC) - identifies existing
interference and chooses
a measurement frequency
to minimize its effect,
providing more accurate
earth ground value
• R* measurement - calculates
earth ground impedance at
55 Hz to more accurately
reflect the earth ground
resistance that a fault-to-
earth ground would see
• Adjustable limits - for
quicker testing
Stakeless testing
The Fluke 1623-2 and 1625-2
earth ground testers are able to
measure earth ground loop resis-
tances using only clamps. With
this test method, two clamps are
placed around the earth ground
rod and each are connected to the
tester. No earth ground stakes are
used at all. A known, fixed voltage
is induced by one clamp and the
current is measured using the
second clamp. Then the tester
automatically determines the
resistance of the earth ground rod.
This test method only works
if a bonded earth ground system
exists for the building or structure
under test, but most are. If there
is only one path to ground, like at
many residential applications, the
Stakeless method will not provide
an acceptable value and the Fall
of Potential test method must
be used.
With Stakeless testing, the
earth ground rod does not need
to be disconnected—leaving the
bonded earth ground system
intact during test. Gone are the
days of spending time placing
and connecting stakes for each
earth ground rod on your system—
a major time saver. You can also
perform earth ground tests in
places you’ve not considered
before: inside buildings, power
pylons, or anywhere you don’t
have access to soil.
The most complete testers
The Fluke 1623-2 and 1625-2
are distinctive earth ground
testers that can perform all
four types of earth ground
measurement:
• 3- and 4-Pole Fall of Potential
(using stakes)
• 4-Pole Soil Resistivity testing
(using stakes)
• Selective testing (using 1 clamp
and stakes)
• Stakeless testing (using 2
clamps only)
The testers are also easy to
use. For each test,
the testers inform you which
stakes or clamps need to be
connected and the large rotary
switch can be used even with a
gloved hand.
The complete model kit comes
with the 1623-2 or 1625-2
tester, test leads, 4 earth ground
stakes, 3 cable reels with wire,
2 clamps, batteries, and manual—
all inside a professional Fluke
carrying case.
2 Fluke Corporation 1623-2 and 1625-2 GEO Earth Ground Testers
General
Display:1999 digit LCD Display with special symbols, digit height 25 mm
User interface Instant measurement through TURN and START one button concept. The only operating elements
are rotary switch and START button
Robust, water and dust resistant Instrument is designed for tough environmental conditions (rubber protective cover, IP56)
Memory Internal memory storage up to 1500 records accessible via USB port
Temperature ranges
Operating temperature -10 °C to 50 °C (14 °F to 122 °F)
Storage temperature -30 °C to +60 °C (-22 °F to +140 °F)
Temperature coefficient ± 0.1 % of reading/°C <18 °C >28 °C
Intrinsic error Refers to the reference temperature range and is guaranteed for 1 year
Operating error Refers to the operating temperature range and is guaranteed for 1 year
Climatic class C1 (IEC 654-1), -5 °C to +45 °C (23° to +115° F), 5 % to 95 % RH
Protective type IP56 for case, IP40 for battery door according to EN60529
Safety Protection by double and/or reinforced insulation. max. 50 V to earth. IEC61010-1: 300V CAT II,
Pollution degree 2
EMC (Emission Immunity) IEC61326-1: Portable
Quality system Developed, designed and manufactured according to DIN ISO 9001
External voltage V ext, max = 24 V (dc, ac < 400 Hz), measurement inhibited for higher values
V ext rejection > 120 dB (162⁄3, 50, 60, 400 Hz)
Measuring time Typical 6 sec.
Max. overload 250 V rms (pertains to misuse)
Auxiliary power 6 x 1.5 V alkaline (type AA LR6)
Battery life span Typical > 3,000 measurements
Dimensions (WxHxD) 250 mm x 133 mm x 187 mm (9.75 in x 5.25 in x 7.35 in)
Weight 1.1 kg (2.43 lb) including batteries
7.6 kg (16.8 lb) including accessories and batteries in carrying case
RA 3-pole ground resistance measurement (IEC 1557-5)
Switch position Resolution Measuring range Accuracy Operating error
RA 3-pole 0.001 Ω to 10 Ω0.020 Ω to 19.99 kΩ± (2 % rdg + 3 d) ± (5 % rdg + 3 d)
For 2-pole measurements connect terminals H and S with the supplied connector cable.
1623-2 Specifications
3 Fluke Corporation 1623-2 and 1625-2 GEO Earth Ground Testers
Measuring principle: Current and voltage measurement
Measuring voltage Vm = 48 V ac
Short-circuit current > 50 mA
Measure frequency 128 Hz
Probe resistance (RS)Max 100 kΩ
Auxiliary earth electrode resistance (RH)Max. 100 kΩ
Additional error from RH and RSRH[kΩ]•••RS[kΩ]/RA[Ω]•••0.2 %
Monitoring of RS and RH with error indicator
Automatic range selection
Measurement is not performed if the current through the current clamp is too low
RA 4-pole ground resistance measurement (IEC 1557-5)
Switch position Resolution Measuring range Accuracy Operating error
RA 4-pole 0.001 Ω to 10 Ω0.020 Ω to 19.99 kΩ± (2 % rdg + 3 d) ± (5 % rdg + 3 d)
Measuring principle: Current/voltage measurement
Measuring voltage Vm = 48 V ac
Short-circuit current > 50 mA
Measuring frequency 128 Hz
Probe resistance (RS+ RES)Max. 100 kΩ
Auxiliary earth electrode resistance (RH)Max. 100 kΩ
Additional error from RH and RSRH[kΩ]•••RS[kΩ/RA[Ω]•••0.2 %
Monitoring of RS, and RH with error indicator
Automatic range selection
RA 3-pole selective ground resistance measurement with current clamp (RA )
Switch position Resolution Measuring range Accuracy Operating error
RA 3-pole 0.001 Ω to 10 Ω0.020 Ω to 19.99 kΩ± (7 % rdg + 3 d) ± (10 % rdg + 5 d)
Measuring principle: Current/voltage measurement (with external current clamp)
Measuring voltage Vm = 48 V ac
Short-circuit current > 50 mA
Measuring frequency 128 Hz
Probe resistance (RS)Max. 100 kΩ
Auxiliary earth electrode resistance (RH)Max. 100 kΩ
Monitoring of RS, and RH with error indicator
Automatic range selection
Measurement is not performed if the current through the current clamp is too low
RA 4-pole selective ground resistance measurement with current clamp (RA )
Switch position Resolution Measuring range Accuracy Operating error
RA 4-pole 0.001 Ω to 10 Ω0.020 Ω to 19.99 kΩ± (7 % rdg + 3 d) ± (10 % rdg + 5 d)
4 Fluke Corporation 1623-2 and 1625-2 GEO Earth Ground Testers
Measuring principle: Current/voltage measurement (with external current clamp)
Measuring voltage Vm = 48 V ac
Short-circuit current > 50 mA
Measuring frequency 128 Hz
Probe resistance (RS)Max. 100 kΩ
Auxiliary earth electrode resistance (RH)Max. 100 kΩ
Monitoring of RS, and RH with error indicator
Automatic range selection
Measurement is not performed if the current through the current clamp is too low
Stakeless ground loop measurement ( )
Switch position Resolution Measuring range Accuracy Operating error
RA 4-pole 0.001 Ω to 0.1 Ω0.020 Ω to 199.9 Ω± (7 % rdg + 3 d) ± (10 % rdg + 5 d)
Measuring principle: Stakeless measurement of resistance in closed loops using two current transformers
Measuring voltage Vm = 48 V ac (primary)
Measuring frequency 128 Hz
Noise current (IEXT)Max. IEXT = 10 A (ac) (RA < 20 Ω)
Max. IEXT = 2 A (ac) (RA > 20 Ω)
Automatic range selection
The information regarding stakeless ground loop measurements is only valid when used in conjunction with the recommended current clamps at the minimum
distance specified.
ST
E
12MKH
k Hz
VmA
nFmH
Test
Limit
HSESE
1625 LCD update
artwork
october 8, 2012
version 2
VA
Reference Image
1:1 Artwork
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5 Fluke Corporation 1623-2 and 1625-2 GEO Earth Ground Testers
Temperature ranges
Operating temperature range -10 °C to 50 °C (14° F to 122° F)
Storage temperature range -30 °C to 60 °C (-22° F to 140° F)
Temperature coefficient ± 0.1 % of range/± 0.1 % of reading/°C <18 °C >28 °C
Type of protection IP56 for case, IP40 for battery door according to EN60529
Max voltage
!
socket to socket
Urms = 0 V
Sockets ” “ to each other in any combination, max. Urms = 250 V (pertains to misuse)
Safety: Protection by double and/or reinforced insulation. Max. 50 V to earth per IEC61010-1. 300V CAT II,
Pollution degree 2
EMC (Emission Immunity) IEC61326-1: Portable
Quality standard Developed, designed and manufactured to comply with DIN ISO 9001
External field influence Complies with DIN 43780 (8/76)
Auxiliary power 6 x 1.5 V alkaline (IEC LR6 or type AA )
Battery life span With IEC LR6/type AA: typ. 3,000 measurements (RE+RH ≤ 1 kΩ)
With IEC LR6/type AA : typ. 6,000 measurements (RE + RH > 10 kΩ)
Dimensions (WxHxD) 250 mm x 133 mm x 187 mm (9.75 in x 5.25 in x 7.35 in)
Weight ≤ 1.1 kg (2.43 lb) without accessories
7.6 kg (16.8 lb) including accessories and batteries in carrying case
Case material Polyester
General
Memory Internal memory storage up to 1500 records accessible via USB port
Measuring function Interference voltage and frequency, earthing resistance 3- and 4-pole with/without clip-on current transformer,
resistance 2-pole with ac, 2- and 4-pole with dc
Display 4 digit (2999 Digit) - 7 segment liquid crystal display, with improved visibility
Operation Central rotary switch and function keys
1625-2 Specifications
6 Fluke Corporation 1623-2 and 1625-2 GEO Earth Ground Testers
Measurement of interference voltage dc + ac (UST)
Measuring Limits of error: method Fullwave rectification
Measuring Range Display Range Resolution Frequency Range Limits of Error
1 V to 50 V 0.0 V to 50 V 0.1 V dc/ac 45 Hz to 400 Hz sine ± (5 % of rdg + 5 digit)
Measuring sequence approx. 4 measurements/s
Internal resistance approx. 1.5 MΩ
Max. overload Urms = 250 V
Measurement of interference frequency (F )
Measuring method Measurement of oscillation period of the interference voltage
Measuring Range Display Range Resolution Range Accuracy
6.0 Hz to 400 Hz 16.0 Hz to 299.9 Hz to 999 Hz 0.1 Hz to 1 Hz 1 V to 50 V ± (1 % of rdg + 2 digit)
Earthing resistance (RE)
Measuring method Current and voltage measurement with probe as IEC61557-5
Open circuit voltage 20/48 V, ac
Short circuit current 250 mA ac
Measuring frequency 94, 105, 111, 128 Hz selected manually or automatic. (AFC) 55 Hz in function R*
Noise rejection 120 dB (162/3, 50 , 60, 400 Hz)
Max. overload Urms = 250 V
Electrical measurement specifications
Intrinsic error or influence
quantity
Reference conditions or specified
operating range
Designation
code
Requirements or test in
accordance with the relevant
parts of IEC 1557
Type
of test
Intrinsic error Reference conditions A Part 5, 6.1 R
Position Reference position ± 90° E1 Part 1, 4.2 R
Supply voltage At the limits stated by the
manufacturer
E2 Part 1, 4.2, 4.3 R
Temperature 0 °C and 35 °C E3 Part 1, 4.2 T
Series interference voltage See 4.2 and 4.3 E4 Part 5, 4.2, 4.3 T
Resistance of the probes and
auxiliary earth electrodes
0 to 100 x RA but ≤ 50 kΩE5 Part 5, 4.3 T
System frequency 99 % to 101 % of the
nominal frequency
E7 Part 5, 4.3 T
System voltage 85 % to 110 % of the nominal voltage E8 Part 5, 4.3 T
Operating error Part 5, 4.3 R
A = intrinsic error
En = variations
R = routine test
T = type test
7 Fluke Corporation 1623-2 and 1625-2 GEO Earth Ground Testers
Measuring
Range Display Range Resolution Accuracy Operating Error
0.020 Ω to 0.001 Ω to 2.999 Ω0.001 Ω± ( 2 % of rdg + 2 digit ) ± ( 5 % of rdg + 5 digit )
300 kΩ3.00 Ω to 29.99 Ω0.01 Ω
30.0 Ω to 299.9 Ω0.1 Ω
0.300 kΩ to 2.999 kΩ1 Ω
3.00 kΩ to 29.99 kΩ10 Ω
30.0 kΩ to 299.9 kΩ100 Ω
Measuring time typ. 8 sec. with a fixed frequency
30 sec. max. with AFC and complete cycle of all measuring frequencies
Additional error because of probe-and auxiliary earth
electrode resistance
Measuring error of RH and RS typ. 10 % of RE + RS + RH
Max. probe resistance ≤ 1 MΩ
Max. auxiliary earth electrode resistance ≤ 1 MΩ
Automatic check if error is kept within the limits required by IEC61557-5.
If after a measurement of probe-, auxiliary earth electrode- and earthing resistance, a measurement error of higher than 30 % is assumed because of the influencing
conditions (see diagram), the display shows a warning symbol
!
and a notice that RS or RH are too high.
Automatic switchover of measuring resolution in
dependence to auxiliary earth electrode resistance RH
RH with Umeas = 48 V RH with Umeas = 20 V Resolution
< 300 Ω< 250 Ω1 mΩ
< 6 kΩ< 2.5 kΩ10 mΩ
< 60 kΩ< 25 kΩ100 mΩ
< 600 kΩ< 250 kΩ1 Ω
Selective measurement of the
earthing resistance (RE )
Measuring method Current and voltage measurement with
probe as per EN61557-5 and current
measurement in the individual branch
with additional current transformer
(patent applied for).
Open circuit voltage 20/48 V ac
Short circuit current 250 mA ac
Measuring frequency 94, 105, 111, 128 Hz selected manually
or automatically (AFC), 55 Hz (R*)
Noise rejection 120 dB (162/3, 50, 60, 400 Hz)
Max. overload Max. Urms = 250 V (measurement will
not be started)
Measuring Range Display range Resolution Intrinsic error* Operating error*
0.020 Ω to 30 kΩ0.001 to 2.999 Ω0.001 Ω± (7 % of rdg + 2 digit) ± (10 % of rdg + 5 digit)
3.00 to 29.99 Ω0.01 Ω
30.0 to 299.9 Ω0.1 Ω
0.300 to 2.999 kΩ1 Ω
3.00 to 29.99 kΩ10 Ω
* With recommended current clamps/transformers.
8 Fluke Corporation 1623-2 and 1625-2 GEO Earth Ground Testers
Additonal error because of probe- and auxiliary earth
typ. electrode resistance
Measuring error of RH and RSTyp. of 10 % of RE TOTA L + RS + RH
Measuring time Typ. 8 sec. with a fixed frequency 30 sec. max. with AFC and complete cycle of
all measuring frequencies
Minimal current in single branch to be measured 0.5 mA With transformer (1000:1)
0.1 mA With transformer (200:1)
Max. interference current through transformer 3 A With a transformer (1000:1)
Resistance measurement (R~)
Measuring method Current and voltage measurement
Measuring voltage 20 V ac, square pulse
Short circuit current > 250 mA ac
Measuring frequency 94, 105, 111, 128 Hz selected manually or automatically (AFC)
Measuring range Display range Resolution Accuracy Operating errors
0.020 Ω to 300 kΩ0.001 Ω to 2.999 Ω0.001 Ω± (2 % of rdg + 2 digit) ± (5 % of rdg + 5 digit)
3.0 Ω to 29.99 Ω 0.01 Ω
30 Ω to 299.9 Ω0.1 Ω
300 Ω to 2999 Ω1 Ω
3.0 kΩ to 29.99 kΩ10 Ω
30.0 kΩ to 299.9 kΩ100 Ω
Measuring time typ. 6 sec.
Max. interference voltage 24 V, with higher voltages measurement will not be started
Max overload Urms max. = 250 V
Resistance measurement (R )
Measuring method current- voltage measurement as per IEC61557-4 possible
Open circuit voltage 20 V dc
Short circuit current 200 mA dc
Formation of measured value with 4-pole measurement wires on H, S, ES can be extended without additional error.
Resistances > 1 Ω in wire E can cause additional error of 5m Ω/Ω.
Measuring range Display range Resolution Accuracy Operating error
0.020 Ω to 3 kΩ0.001 Ω to 2.999 Ω0.001 Ω± (2 % of rdg + 2 digit) ± (5 % of rdg + 5 digit)
3.0 Ω to 29.99 Ω0.01 Ω
30.0 Ω to 299.9 Ω0.1 Ω
300 Ω to 2999 Ω1 Ω
Measuring sequence Approx. 2 measurements/s
Measuring time Typ. 4 sec. incl. reversal of polarity (2-pole or 4-pole)
Max. interference voltage ≤ 3 V ac or dc, with higher voltages measurement will not be started
Max inductivity 2 Henry
Max. overload Urms = 250 V
9 Fluke Corporation 1623-2 and 1625-2 GEO Earth Ground Testers
Compensation of lead resistance (RK)
Compensation of lead resistance (RK) can be switched on in functions RE 3-pole, RE 4-pole , R~ , and R 2-pole
Formation of measured value Rdisplay = Rmeasured - Rcompensated*
* Value of setpoint entry RK = 0.000 Ω, variable from 0.000 to 29.99 Ω by means of measuring adjustment.
Stakeless ground loop measurement ( )
Switch position Resolution Measuring range Accuracy Operating error
RA 4-pole 0.001 Ω to 0.1 Ω0.02 Ω to 199.9 Ω± (7 % rdg + 3 d) ± (10 % rdg + 5 d)
Measuring principle: Stakeless measurement of resistance in closed loops using two current transformers
Measuring voltage Vm = 48 V ac (primary)
Measuring frequency 128 Hz
Noise current (IEXT)Max. IEXT = 10 A (ac) (RA < 20 Ω)
Max. IEXT = 2 A (ac) (RA > 20 Ω)
Automatic range selection
The information regarding stakeless ground loop measurements is only valid when used in conjunction with the recommended current clamps at the minimum
distance specified.
10 Fluke Corporation 1623-2 and 1625-2 GEO Earth Ground Testers
Ordering information
Fluke-1623-2 Kit Basic GEO Earth Ground Tester Kit
Fluke-1623-2 Basic GEO Earth Ground Tester
EI-1623 Selective/Stakeless Clamp Set for 1623
Fluke-1625-2 Kit Advanced GEO Earth Ground Tester Kit
Fluke-1625-2 Advanced GEO Earth Ground Tester
EI-1625 Selective/Stakeless Clamp Set for 1625
Optional accessories
ES-162P3-2 Stake Set for 3-Pole Measurement
ES-162P4-2 Stake Set for 4-Pole Measurement
EARTH STAKE Ground/Earth Stake
CABLE REEL 25M BL Ground/Earth Cable Reel 25 m (81.25 ft)
CABLE REEL 25M GR Ground/Earth Cable Reel 25 m (81.25 ft)
CABLE REEL 50M RD Ground/Earth Cable Reel 50 m (162.5 ft)
EI-162BN 320 mm (12.6 in) Split Core Transformer
EI-162X Clip-on Current Transformer (Sensing)
with Shielded Cable Set
EI-162AC Clip-on Current Transformer (Inducing)
Selection guide by user
Field Service
Technician
Industrial
Maintenance
Technician
Power Utilities
and Telecom
Fluke 1623-2 • •
Fluke 1625-2 • •
Standard earth ground test methods
Fall of Potential Selective Stakeless
3-pole 4-pole/soil 1 clamp 2 clamps
Fluke 1623-2 ••••
Fluke 1625-2 ••••
Fluke Corporation
PO Box 9090, Everett, WA 98206 U.S.A.
Fluke Europe B.V.
PO Box 1186, 5602 BD
Eindhoven, The Netherlands
For more information call:
In the U.S.A. (800) 443-5853 or
Fax (425) 446-5116
In Europe/M-East/Africa +31 (0) 40 2675 200 or
Fax +31 (0) 40 2675 222
In Canada (800)-36-FLUKE or
Fax (905) 890-6866
From other countries +1 (425) 446-5500 or
Fax +1 (425) 446-5116
Web access: http://www.fluke.com
©2013 Fluke Corporation. Specifications subject to change
without notice. Printed in U.S.A. 11/2013 2634980C-EN
Modification of this document is not permitted without
written permission from Fluke Corporation.
Fluke. The Most Trusted Tools
in the World.
