• Megger

Megger® DET5D & DET4D

Digital Ground ResistanceTesters

Megger DET5D/DET4D


  • Simple, fully automatic operation
  • Choice of three or four terminal measurement
  • Auto-ranging from 10 m½ to 20 k½
  • Tests to BS7671, BS7430, BS6651 and VDE 0413
  • High tolerance to spike resistance helps testing in urban areas
  • Noise rejection to 40 V
  • Simple to use, one touch operation
  • Auto switch off to save battery power
  • Rugged, weatherproof case
  • Large, clear LCD
  • Noise rejection to 40 V
  • Indicators show if reading may be invalid
  • Terminal shorting bars supplied
  • Earth testing kits available
  • Optional carrying case and harness


The Megger® DET5/4D and DET5/4R are fully automatic, four terminal instruments built into a rugged, water resistant case giving protection for outdoor use. The instrument is suitable for the testing of earth electrodes and measuring earth resistivity.

Operation is started by pushing one of two buttons on the front panel; one for three terminal measurement and one for four terminal testing. All other functions of the instrument are completely automatic. The instrument checks for conditions that may cause an invalid reading during a test. The low service error and wide operating temperature range enable accurate results to be achieved in real on-site conditions.

There are four ranges covering measurements from 10 mohm; to 20 kohm. The earth resistance reading is displayed quickly, accurately and directly on a large, clear 31⁄2 digit liquid crystal display. The display indicates when there is a high test spike resistance and also when the noise interference is too high to take a valid reading. If the batteries need replacing or recharging this will also be shown on the display.

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Six 1,5 V AA dry cells provide power for the DET5/4D allowing 600 typical 15 second tests. The DET5/4R is powered by an internal rechargeable, lead acid battery. This instrument has a built in battery charger that can operate from a wide range of mains voltages. The capacity of the lead acid battery enables 600 typical 15 s tests to be made from one charge.

Each instrument is built into a small, lightweight case with a handle that has been designed for outdoor use and has IP54 protection. Four large terminals allow either spade or hook connectors, 4 mm plugs or bare ended wire to be used for the test leads. Terminal Shorting bars are provided for continuity testing or measurement using the ‘dead earth’ method. A removable cover allows access to the battery compartment in the DET5/4D or to the charger socket in the DET5/4R.


  • The DET5/4D and DET5/4R digital earth testers are reliable instruments able to measure the earth resistance of both simple and complex electrode systems. They may be used to test in accordance with BS7430 (1991), BS6651 (1992) BS7671 (the 16th Edition of the IEE wiring regulations), NFC15-100, IEC364 and VDE 0413 part 7 (1982). The instruments are suitable for soil resistivity measurements which are used to establish the optimum earth electrode system design and location, to avoid expensive reworking of electrical installations. They are also suitable for performing archeological and geological investigations.
  • The direct indication of excessive noise and high spike resistances avoids measurement errors and lengthy testing of these parameters. The direct digital reading is unambiguous, avoids errors and assists in faster, more economic testing.
  • Earth testing kits including test spikes and leads, and a book describing several testing techniques are also available.
  • Literature
  • Specifications
Ground Resistance Ranges:
20 Ω Range: 0,01 Ω to 19,99 Ω
200 Ω Range: 0,1 Ω to 199,9 Ω
2 kΩ Range: 0,001 kΩ to 1,999 kΩ
20 kΩ Range: 0,01 kΩ to 19,99 kΩ
Accuracy (at 23°C): ±7.5% ±3 digits (±10% at >0.5 ohms and ±0.05 ohm at <0.5 ohms for
KEMA K85B requirements.
Total service error: ±7.5% ±3 digits (±10% at >0.5 ohms and ±0.05 ohm at <0.5 ohms for
KEMA K85B requirements.

31⁄2 digit L.C.D. with ½, k½ and low battery voltage indicators.
LEDs for high noise, high voltage probe resistance and high
current loop resistance.

Test Frequency: 128 Hz ±0.5 Hz
Test Voltage: Maximum 50 Volts peak.
Test Current:
20 Ω Range: 10 mA a.c. r.m.s.
200 Ω Range: 1 mA a.c. r.m.s.
2 kΩ, 20 kΩ Range: 100 μA a.c. r.m.s.
Power Supply:
DET5/4D ;6 x 1,5 V (AA) IEC LR6 cells giving 600 typical 15 s
tests at 20°C (68°F).
DET5/4R Rechargeable version (12 V, 0,8 Ah) from 110/120 V
or 220/240 V (user selectable) 50/60 Hz supplies giving 600
typical 15 s.
Temperature Range: Operating:
-20°C to +45°C (-4 to113°F)Storage:
-40°C to +70°C (-40 to 158°F) (DET5/4D, without batteries)
Operating: 90% RH max. at 113° F (45°C)Storage: 70% RH max. at 131° F (55° C)
Temperature Coefficient: ±0,1% per °C over the temperature range -15°C to +45°C±0,05% per °F over 5°F to 113°F
Voltage Withstand: 250 V a.c. between any two terminals.
The instruments meet the requirements of IEC1010-1.
243 mm x 161 mm x 70 mm(9,4 in x 6 in x 2,75 in approx.)
Weight: DET5/4D:
0,82 kg (1,5 lb approx.)DET5/4R:
1,27 kg (2,8 lb approx.)