Description

The Fluke 1625-2 Advanced Geo Earth Ground Tester sets the standard for professional earth resistance testing, combining multiple measurement functions in a single, rugged instrument. Technicians and engineers rely on this versatile device to verify grounding system integrity across diverse installation environments, from industrial facilities to commercial buildings. The instrument’s ability to measure earth resistance using both 3-pole and 4-pole methods, along with interference voltage and frequency analysis, makes it an essential tool for ensuring electrical safety and code compliance.

Fluke 1625-2 Key Features

The Fluke 1625-2 delivers comprehensive grounding verification through its advanced multi-function capability. Beyond standard earth resistance measurements, it simultaneously measures interference voltage and frequency, providing critical data about power quality issues that affect grounding performance. The large 4-digit LCD display ensures clear readings in various lighting conditions, while the IP56-rated case protects against dust and water ingress during field use. Internal memory stores up to 1500 readings, transferable via USB for reporting and analysis.

Interference voltage measurement: 1 V to 50 V AC/DC
Interference frequency range: 45 Hz to 400 Hz
Earth resistance measurement: 3- and 4-pole methods with/without clip-on current transformer
2-pole resistance measurement with AC and DC
Internal memory: 1500 records accessible via USB
Operating temperature: -10°C to 50°C
IP56 case rating for rugged field use
Battery life: 3000+ measurements per battery set

Who Needs the Fluke 1625-2?

Electrical maintenance technicians responsible for routine grounding system testing will find the Fluke 1625-2 indispensable for verifying that earth electrodes maintain proper resistance levels. Field engineers performing site acceptance testing on new installations depend on its accurate measurements to confirm compliance with local electrical codes and standards. Building maintenance teams use the device to troubleshoot nuisance tripping and power quality issues by analyzing interference patterns on the grounding system. Procurement buyers specifying grounding test equipment for organizational fleets appreciate the Fluke brand reputation for reliability and the instrument’s versatile measurement capabilities that replace multiple standalone devices.

The Fluke 1625-2’s ability to measure interference voltage makes it particularly valuable for facilities experiencing stray voltage issues or electromagnetic interference affecting sensitive equipment. Grounding contractors performing seasonal maintenance cycles benefit from the internal memory storage, which streamlines data collection and report generation without requiring separate data logging equipment. Any professional tasked with ensuring personnel safety and equipment protection through proper grounding will rely on the Fluke 1625-2’s comprehensive measurement suite.

Fluke 1625-2 Applications

Industrial facilities use the Fluke 1625-2 to verify grounding systems for large motors, transformers, and switchgear, ensuring fault currents have a reliable path to earth during fault conditions. Commercial buildings rely on the instrument to test grounding of lightning protection systems, elevator equipment, and HVAC systems, protecting both occupants and sensitive electronics from surge damage. Telecommunications sites depend on accurate earth resistance measurements to maintain proper grounding for antenna systems and radio equipment, preventing interference and ensuring reliable operation. Utility companies utilize the Fluke 1625-2 for substation grounding verification and transmission line tower testing, where grounding system integrity is critical for public safety and grid stability.

The interference voltage measurement function proves especially useful in environments with high electronic noise, such as data centers, hospitals, and manufacturing facilities with variable frequency drives. The Fluke 1625-2 aids in troubleshooting grounding-related power quality issues that can cause equipment malfunction or unexpected shutdowns. Regular testing with this instrument helps facilities maintain compliance with IEEE and IEC grounding standards while identifying degradation in grounding systems before they cause costly downtime or safety hazards.

Why Buy Fluke 1625-2 from MME?

MME stands behind the Fluke 1625-2 Advanced Geo Earth Ground Tester with genuine product support and warranty service that customers expect from an MME. When you purchase from mme-ae, you receive authentic Fluke instrumentation with the complete manufacturer’s documentation and calibration certificates required for your quality assurance programs. Our knowledgeable team understands the technical requirements of grounding testing and can advise on measurement methodology selection for your specific application needs. We maintain stock availability of the Fluke 1625-2 so your projects stay on schedule without waiting for international shipments.

Mohammad Mahdi Electronics ensures every Fluke 1625-2 unit ships with the protective carrying case, test leads, and necessary accessories for immediate deployment upon arrival. Our after-sales support includes technical assistance for measurement interpretation and troubleshooting, helping you get the most value from your investment in grounding testing equipment. Trust MME for reliable service, authentic products, and the expertise to support your electrical testing requirements.

General Specifications

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
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
Type of protection: IP56 for case, IP40 for battery door according to EN60529
Max voltage: Warning – socket “clamp” to socket E, ES, S or H; U rms = 0 V; Sockets E, ES, S or H to each other in any combination, max. U rms = 250 V (pertains to misuse)
Safety: Protection by double and/or reinforced insulation. Max. 50 V to earth per IEC61010-1. Pollution degree 2
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 (R E +R H ≤ 1 kΩ); With IEC LR6/type AA: typ. 6,000 measurements (R E + R H > 10 kΩ)
Dimensions (W x H x D): 250 x 133 x 187 mm (9.75 x 5.25 x 7.35 in)
Weight: ≤ 1.1 kg (2.43 lb) without accessories; 7.6 kg (16.8 lb) incl. accessories and batteries in carrying case
Case material: Polyester

Measurement of Interference Voltage DC + AC (U ST )

Measuring limits of error: method: Full wave rectification
Measuring range: 1 V to 50 V
Display range: 0.0 V to 50 V
Resolution: 0.1 V
Frequency range: DC/AC 45 Hz to 400 Hz sine
Accuracy: ±(5% of rdg + 5 digit)

Measurement of Interference Frequency (F)

Measuring limits of error: method: Measurement of oscillation period of the interference voltage
Measuring range: 6.0 Hz to 400 Hz
Display range: 16.0 Hz to 299.9 Hz to 999 Hz
Resolution: 0.1 Hz to 1 Hz
Range: 1 V to 50 V
Accuracy: ±(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 1
Noise rejection: 120 dB (16 2/3 , 50

Call our team at MME to discuss your Fluke 1625-2 requirements or place your order today. We’re ready to help you find the right grounding testing solution for your project.

Fluke 1625-2 Specifications

General Specifications
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
Temperature Range
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
Type of protection	IP56 for case, IP40 for battery door according to EN60529
Max voltage	Warning – socket “clamp” to socket E, ES, S or H
	U_rms = 0 V
	Sockets E, ES, S or H to each other in any combination, max. U_rms = 250 V (pertains to misuse)
Safety	Protection by double and/or reinforced insulation. Max. 50 V to earth per IEC61010-1. Pollution degree 2
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 (R_E+R_H ≤ 1 kΩ)
	With IEC LR6/type AA: typ. 6,000 measurements (R_E + R_H > 10 kΩ)
Dimensions (W x H x D)	250 x 133 x 187 mm (9.75 x 5.25 x 7.35 in)
Weight	≤ 1.1 kg (2.43 lb) without accessories 7.6 kg (16.8 lb) incl. accessories and batteries in carrying case
Case material	Polyester
Measurement of Interference Voltage DC + AC (U_ST)
Measuring limits of error: method	Full wave rectification
Measuring range	1 V to 50 V
Display range	0.0 V to 50 V
Resolution	0.1 V
Frequency range	DC/AC 45 Hz to 400 Hz sine
Accuracy	±(5% of rdg + 5 digit)
Measuring sequence	Approx. 4 measurements/s
Internal resistance	Approx. 1.5 MΩ
Max. overload	U_rms = 250 V
Measurement of Interference Frequency (F)
Measuring limits of error: method	Measurement of oscillation period of the interference voltage
Measuring range	6.0 Hz to 400 Hz
Display range	16.0 Hz to 299.9 Hz to 999 Hz
Resolution	0.1 Hz to 1 Hz
Range	1 V to 50 V
Accuracy	±(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 R¹
Noise rejection	120 dB (16 2/3 , 50 , 60, 400 Hz)
Max. overload	U_rms = 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 R_A but ≤ 50 kΩ	E5	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	B = ±(\|A\| + 1,15 √E²₁ E²₂ E²₃ E²₄ E²₅ E²₆)		Part 5, 4.3	R
	B[%] = ± B/fiducial value x 100% A = intrinsic error E_n = variations R = routine test T = type test
Measuring range	0.020 Ω to 300 kΩ
Display range	0.001 Ω to 2.999 Ω
	3.00 Ω to 29.99 Ω
	30.0 Ω to 299.9 Ω
	0.300 kΩ to 2.999 kΩ
	3.00 kΩ to 29.99 kΩ
	30.0 kΩ to 299.9 kΩ
Resolution	0.001 Ω
	0.01 Ω
	0.1 Ω
	1 Ω
	10 Ω
	100 Ω
Accuracy	±(2% of rdg + 2 digit)
Operating error	±(5% of rdg + 5 digit)
Measuring time	Typical 8 seconds 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	R_H(R_S + 2000 Ω)/R_E x 1.25 x 10^-6% + 5 digits
Measuring error of R_H and R_S	Typ. 10% of R_E + R_S + R_H
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, 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 R_H
RH with U_meas = 48 V	< 300 Ω
	< 6 Ω
	< 60 Ω
	< 600 Ω
RH with U_meas = 20 V	< 250 Ω
	< 2.5 kΩ
	< 25 kΩ
	< 250 kΩ
Resolution	1 mΩ
	10 mΩ
	100 mΩ
	1 Ω
Selective Measurement of the Earthing Resistance (R_E Clamp)
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 (R¹)
Noise rejection	120 dB (162/3, 50, 60, 400 Hz)
Max. overload	Max. U_rms = 250 V (measurement will not be started)
Measuring range	0.020 Ω to 300 kΩ
Display range	0.001 Ω to 2.999 Ω
	3.00 Ω to 29.99 Ω
	30.0 Ω to 299.9 Ω
	0.300 kΩ to 2.999 kΩ
	3.00 kΩ to 29.99 kΩ
Resolution	0.001 Ω
	0.01 Ω
	0.1 Ω
	1 Ω
	10 Ω
Accuracy	±(7% of rdg + 2 digit)
Operating error	±(10% of rdg + 5 digit)
Additional error because of probe- and auxiliary earth typ. electrode resistance	R_H(R_S + 2000 Ω)/R_ETOTAL x 1.25 x 10^-6% + 5 digits
Measuring error of R_H and R_S	Typ. of 10% of R_ETOTAL + R_S + R_H
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 transformer (1000:1)
1. With recommended current clamps/transformers.
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	0.020 Ω to 300 kΩ
Display range	0.001 Ω to 2.999 Ω
	3.00 Ω to 29.99 Ω
	30.0 Ω to 299.9 Ω
	300 Ω to 2999 Ω
	3.00 kΩ to 29.99 kΩ
	30.0 kΩ to 299.9 kΩ
Resolution	0.001 Ω
	0.01 Ω
	0.1 Ω
	1 Ω
	10 Ω
	100 Ω
Accuracy	±(2% of rdg + 2 digit)
Operating error	±(5% of rdg + 5 digit)
Measuring time	Typical 6 seconds
Max. interference voltage	24 V, with higher voltages measurement will not be started
Max overload	U_rms max. = 250 V
Resistance Measurement (R DC)
Measuring method	Current- voltage measurement as per IEC61557-4 possible
Measuring voltage	20 V DC
Short circuit current	250 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	0.020 Ω to 300 kΩ
Display range	0.001 Ω to 2.999 Ω
	3.00 Ω to 29.99 Ω
	30.0 Ω to 299.9 Ω
	300 Ω to 2999 Ω
	3.0 kΩ to 29.99 kΩ
	30.0 kΩ to 299.9 kΩ
Resolution	0.001 Ω
	0.01 Ω
	0.1 Ω
	1 Ω
	10 Ω
	100 Ω
Accuracy	±(2% of rdg + 2 digit)
Operating error	±(5% of rdg + 5 digit)
Measuring sequence	Approx. 2 measurements/s
Measuring time	Typical 4 second including reversal of polarity (2-pole or 4-pole)
Maximum interference voltage	≤ 3 V AC or DC, with higher voltages measurement will not be started
Maximum inductivity	2 Henry
Maximum overload	U_rms = 250 V
Compensation of Lead Resistance (R_K)
Compensation of lead resistance (R_K) can be switched on in functions R_E 3-pole, R_E 4-pole (clamp), R AC, and R DC 2-pole
Formation of measured value	R_display = R_measured – R_compensated²
2. 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 (Two Clamp Stakeless)
Switch position	RA 4-pole (two clamp Stakeless)
Resolution	0.001 Ω to 0.1 Ω
Measuring range	0.02 Ω to 199.9 Ω
Accuracy	±(7% rdg + 3 digit)
Operating error	±(10% rdg + 5 digit)
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)
Measuring principle: Stakeless measurement of resistance in closed loops using two current transformers. 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.