The MJ159 insulation resistance tester provides excellent test voltage regulation and is the ideal instrument when high ranges are needed for measuring insulation resistance. It also has an external guard terminal to eliminate surface leakage current from the measurement.
The instrument generates a regulated DC high voltage and use low-zero-drift, high-accuracy circuits, with high current sensitivity. Designed for portability, it is enclosed in a moulded, impact-resistance, flame-retardant case that is made with ABS plastic with a fold down carrying handle.
The MJ159 is operated by a low voltage, hand-cranked generator that has been designed to be easy to turn even under full load conditions. The low voltage generator is connected to an electronic inverter to provide a very stable test voltage. Accuracy of measurement is unaffected by variations in the generator cranking speed and the test voltage is maintained at its rated value. The MJ159 has four selectable test voltages of 100, 250, 500, and 1000 V DC. It measures insulation resistance up to 2000 MΩ, and an ohm range to 5000 Ω.
As a safety feature, the AC voltage range becomes effective as soon as the instrument is connected to the circuit under test. Therefore, a warning is given that the circuit under test is not de-energised before the instrument is operated. Though calibrated for AC voltage, this range also monitors the automatic discharge feature so that after equipment having capacitance (i.e., a cable), has been tested, an indication can be given that the voltage has discharged to a level that is safe for removing the test leads.
It is portable and self-contained, designed to give rapid and accurate measurements. The instrument is protected for connection to power distribution systems up to 300 V Line-Ground and 500 V Line-Line for Installation Category III. This relates to transient overvoltage likely to be found in fixed installation wiring.
Please note that the 210600, 21017 and MJ359 have been discontinued.
The MIT480/2 series of insulation and continuity testers replace the original MIT480 range and are designed specifically for the telecommunications and cable testing markets. The new units feature a redesigned case, back stand, and six-cell battery compartment with separate fuse access. All instruments are over-molded for increased protection and have an IP54 weatherproof rating.
The MIT480/2 series uses a three-terminal measurement design that permits the connection of all three test leads for A, B, and E (or Tip, Ring and Ground/Earth). The measurement pair can be selected from the A-B-E (T-R-G) button on the front panel and the selection is confirmed in the display. You don't need to disconnect the test leads to measure individual pairs.
Alternatively, the units can be used as a conventional two-terminal instrument.
The range consists of two instruments:
MIT481/2: 50 V, 100 V, 250 V, 500 V* + storage
MIT485/2: 50 V, 100 V, 250 V, 500 V* + storage + download + recharge ready
* Gated access – prevents accidental selection
The Megger Advanced range of 5 kV, 10 kV, and 15 kV insulation resistance testers is ideal for engineers and technicians performing insulation testing on transformers, motors, switchgear, and cables in environments up to 230 kV. These instruments support IR, DAR, PI, DD, SV, ramp, and PDC (with software), providing the diagnostic depth needed for condition assessment and maintenance planning.
Each model includes PI Predictor™ to speed up testing, internal memory for storing results, and optional Bluetooth® for exporting data to PowerDB or CertSuite — no manual recording required.
The new innovative patent applied RE>Act test mode allows the user to make accurate measurements by monitoring reabsorption current. This groundbreaking test mode can ensure reabsorption current does not result in incorrectly passing or failing insulation, helping to maintain safety. In addition, the test mode can be used to ensure dangerous return voltages to not occur.
Choose from three models — MIT525/2, MIT1025/2, and MIT1525/2 — based on your required test voltage. With 6 mA noise immunity and high-performance guard terminals, the Advanced range delivers reliable results where remote control and substation-level noise handling are not required.
The range includes three models: S1-568/2 (5 kV), S1-1068/2 (10 kV), and S1-1568/2 (15 kV). All are trusted by utility engineers, OEMs, and commissioning teams working on critical assets like transformers, cables, switchgear, and bushings.
The adaptive filter, nearly unique to Megger, monitors the rate of change in noise current and applies dynamic damping to prevent test current distortion. It predicts spikes that would otherwise affect results and stabilises readings — even during energisation events or switching noise.
Test modes include IR, DAR, PI, DD, SV, ramp, and PDC (with software). PI Predictor™ reduces Polarisation Index test time by up to 50%, and RE>Act™ shows when insulation is safe to retest, saving time and reducing risk.
Fully remote control via Bluetooth® or USB enables testing from a safe distance — or even from the comfort of an air-conditioned vehicle during extreme site conditions. Onboard memory and no-dongle Bluetooth® make data transfer seamless. High-performance guard terminals ensure measurement accuracy even with high surface leakage.
With CAT IV safety ratings, robust design, and powerful time-saving tools, the Megger Expert range gives HV professionals the speed, safety, and confidence they need to test without compromise.
