Megger MIT520-2 Insulation Tester

Megger MIT 520/2 5 kV Insulation Resistance Tester

The Megger MIT 520/2 is a 5 kV insulation resistance tester used by electrical engineers, electrical contractors, and industrial maintenance teams in Ireland to commission, maintain, and troubleshoot high-voltage assets, switchgear, large motors, transformer windings, and long cable runs. It is the 5 kV class IR tester that gives you the test voltage to find insulation problems on assets where a 1 kV or 2.5 kV instrument simply does not stress the insulation enough to reveal them.

For HV cable, motors, generators, and transformer windings, insulation resistance is one of the simplest and most diagnostic measurements available. A trended IR value, captured the same way each time at the same test voltage, is what tells you whether the insulation is healthy, drying out after a wet weekend, or quietly degrading toward a failure.

What the MIT 520/2 measures

• Insulation resistance (IR): spot measurement of insulation resistance at a selectable test voltage from low-voltage levels up to 5 kV.
• Polarisation index (PI): the ratio between 10-minute and 1-minute readings, a strong indicator of insulation contamination and ageing in motors and generators.
• Dielectric absorption ratio (DAR): a faster equivalent ratio test useful for shorter test windows.
• Step voltage (SV) test: a stepped IR test that reveals voltage-dependent breakdown that single-voltage tests miss.
• Insulation discharge (DD): dielectric discharge test for assessing multi-layer insulation systems.

One handheld instrument, the full diagnostic IR toolkit, with results stored on-board and exportable for the maintenance record.

Key features

• 5 kV test voltage with a wide selectable range from low-voltage insulation tests up to the full 5 kV.
• Up to 10 TΩ insulation resistance range: covers modern high-quality cable and rotating machine insulation that lower-class testers cannot resolve.
• CAT IV 600 V safety rating: cleared for use at the service entrance and through the LV distribution.
• Rugged handheld form built for substation and switchroom field work.
• Result storage and export with battery status and time-constant readouts during the test.
• Test modes covering IR, PI, DAR, DD, and SV in a single instrument from the wider Megger MIT series of 5 kV insulation resistance testers.

Specifications: what to confirm before you order

Target users and applications

• Electrical engineers commissioning HV switchgear, large motors, and generators
• Electrical contractors carrying out periodic insulation testing on industrial cable systems
• Utility and renewable site teams testing transformer windings, MV cable, and switchgear bushings
• Industrial maintenance teams running insulation health programmes on critical assets
• Test specialists using PI, DAR, and step-voltage methods for trended condition assessment

Typical applications include commissioning IR tests on new HV cable runs, periodic IR and PI testing of large motors and generators, transformer insulation testing during planned maintenance, and post-fault diagnostic IR work after an insulation failure.

As authorised Megger distributor in Ireland, Powerpoint Engineering supports the MIT 520/2 with in-house calibration and repair, accessory supply, and operator training in HV insulation resistance testing techniques.

FAQs

When should I use a 5 kV insulation tester instead of a 1 kV unit?

A 5 kV tester applies enough test voltage to stress modern HV cable, motor, generator, and transformer insulation properly. A 1 kV tester is fine for general LV installations, but it cannot detect a developing insulation problem on a 6.6 kV motor or an 11 kV cable. For HV assets, choose the appropriate IR tester class.

What is the difference between IR, PI, and DAR tests?

IR is a spot insulation resistance reading. PI compares 10-minute to 1-minute readings to assess how the insulation behaves over time, useful on motors and generators. DAR is a quicker equivalent ratio test using shorter intervals when a 10-minute PI is not practical.

Does the MIT 520/2 need calibration?

Yes. Like any precision IR tester, the MIT 520/2 should be recalibrated periodically to remain trusted against acceptance and trending criteria. Powerpoint Engineering's calibration laboratory recalibrates Megger insulation testers in-house and supplies a traceable certificate.

To match the right MIT 520/2 configuration to your HV assets and reporting requirements, request a quote or speak to our team for compatibility advice.