Testing Methods
- 3- and 4-Pole Fall of Potential – standard earth ground testing using two ground stakes
- Selective testing – without disconnecting ground rods, a technician can measure ground resistance using a combination of stakes and a clamp.
- Stakeless testing – innovative solution using only clamps, instead of ground stakes, to measure earth ground loop resistance
The Fluke 1625 offers these advanced features
- Automatic Frequency Control (AFC) – identifies existing interference and chooses a measurement frequency to minimize its effect, providing a 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 quick test result verification.
- 3- and 4-pole earth ground measurement
- 4-Pole soil resistivity testing
- 2-pole resistance measurement AC
- 2- and 4-pole resistance measurement DC
- Selective testing, no disconnection of ground conductor (1 clamp)
- Stakeless testing, quick ground loop testing (2 clamps)
- Earth impedance measurement at 55 Hz
- Automatic frequency control (AFC) (94, 105, 111, 128 Hz)
- Measuring voltage switchable 20/48V
- Programmable limits, settings
- Continuity with buzzer
| RA 3-pole Ground Resistance Measurement (IEC 1557-5) | |
| Measuring voltage | Vm = 20/48 V AC | 
| Short circuit current | 250 mA AC | 
| Measure frequency | 94, 105, 111, 128Hz | 
| Resolution | 0.001 Ω to 100 Ω | 
| Measuring range | 0.001 Ω to 299.9 kΩ | 
| Intrinsic error | ± (2 % of reading + 2 d) | 
| Operating error | ± (5 % of reading + 5 d) | 
| RA 4-pole Ground Resistance Measurement (IEC 1557-5) | |
| Measuring voltage | Vm = 20/48 V AC | 
| Short circuit current | 250 mA AC | 
| Measure frequency | 94, 105, 111, 128Hz | 
| Resolution | 0.001 Ω to 100 Ω | 
| Measuring range | 0.001 Ω to 299.9 kΩ | 
| Intrinsic error | ± (2 % of reading + 2 d) | 
| Operating error | ± (5 % of reading + 5 d) | 
| RA 3-pole Ground Resistance Measurement With Current Clamp | |
| Measuring voltage | Vm = 20/48 V AC | 
| Short circuit current | 250 mA AC | 
| Measure frequency | 94, 105, 111, 128Hz | 
| Resolution | 0.001 Ω to 10 Ω | 
| Measuring range | 0.001 Ω to 29.99 kΩ | 
| Intrinsic error | ± (7 % of reading + 2 d) | 
| Operating error | ± (10 % of reading + 5 d) | 
| RA 4-pole Selective Ground Resistance Measurement With Current Clamp | |
| Measuring voltage | Vm = 20/48 V AC | 
| Short circuit current | 250 mA AC | 
| Measure frequency | 94, 105, 111, 128Hz | 
| Resolution | 0.001 Ω to 10 Ω | 
| Measuring range | 0.001 Ω to 29.99 kΩ | 
| Intrinsic error | ± (7 % of reading + 2 d) | 
| Operating error | ± (10 % of reading + 5 d) | 
| Stakeless Ground Loop Measurement | |
| Measuring voltage | Vm = 20/48 V AC | 
| Measure frequency | 94, 105, 111, 128Hz | 
| Noise current (Iext) | Max. Iext = 3 A | 
| Resolution | 0.001 Ω to 10 Ω | 
| Measuring range | 0.001 Ω to 29.99 kΩ | 
| Intrinsic error | ± (7 % of reading + 2 d) | 
| Operating error | ± (10 % of reading + 5 d) | 
| Environmental Specifications | |
| Working temperature | -10 °C to +50 °C | 
| Operating temperature | 0 °C to +35 °C | 
| Nominal temperature | +18 °C to +28 °C | 
| Storage temperature | -30 °C to +60 °C | 
| Climatic class | C1 (IEC 654-1), -5 °C to + 45 °C, 5 % to 95 % RH | 
| Protection type | IP56 for case, IP40 for battery door according to EN 60529 | 
| Safety Specifications | |
| Safety rating | CAT II, 300 V | 
| Mechanical And General Specifications | |
| Display | 2999 Digit LCD – 7 segment liquid crystal display with special symbols and backlight | 
| Size | 133 mm x 187 mm x 250 mm | 
| Weight | 1.1 kg (including batteries) | 
| Warranty | Two years | 
| Battery life | Typical 3000 measurements (RE+RH ≤ 1 kΩ) | 
| Typical 6000 measurements (RE+RH ≤ 10 kΩ) | |
 
