Megger's new series of insulation resistance testers combines the previous Megger MIT and S1 ranges to create one comprehensive set offering models suitable for various testing applications. Ideal for engineers and technicians working in power utilities, industry, rail, production/manufacturing, and other high-voltage sectors, the new Megger MIT & S1 series comprises eight models organised into three levels of functionality: Essential, Advanced, and Expert. To find out what the differences are between these Megger insulation resistance testers and get an idea of which model might be right for you, below we've outlined the details of this range and Megger's application advice.
Quick Links
- NEW Megger MIT & S1 Insulation Resistance Testers
- What’s the Difference Between Megger’s NEW Insulation Testers?
- What’s NEW with the Megger MIT & S1 Insulation Resistance Testers?
- Further Information
NEW Megger MIT & S1 Insulation Resistance Testers
Megger’s MIT and S1 Insulation Resistance Testers have been restructured, renamed, and relaunched as Mark 2 models. These new Mark 2 models are denoted by the “/2” and have been updated for enhanced performance. Customers will be pleased to know that, in addition to retaining Megger’s impeccable quality, the price of these new insulation testers remains unchanged from their Mark 1 counterparts (as of August 2025). Megger’s restructuring of the MIT & S1 range is to reflect the purchasing habits of customers, making it easier for you to choose the best model based on your testing requirements.
Megger NEW MIT & S1 Insulation Resistance Tester
Megger MIT Insulation Resistance Tester, Essential Range (MIT515/2 & MIT1015)
Megger MIT Insulation Resistance Tester, Advanced Range (MIT525/2, MIT1025/2 & MIT1525/2)
Megger S1 Insulation Resistance Tester, Expert Range (S1-568/2, S1-1068/2 & S1-1568/2)
Additionally, Megger has introduced a new MIT1015 Insulation Tester. This new insulation resistance tester has a 10kV capability and the capacity to perform all commonly used tests. As an ‘Essential’ model, it delivers the 10kV testing you require without unnecessary extra functions. This way, you only pay for the functionality you need.
Read More About the NEW Megger MIT1015 Insulation Tester
What’s the Difference Between Megger’s NEW Insulation Testers?
As mentioned, Megger has categorised the MIT & S1 Series Insulation Testers into three levels of functionality: Essential, Advanced, and Expert. Each level builds on the features and tests of the category before it. Below, we outline the capabilities of these insulation testers; detail the instruments in each category; and provide guidance on which models might be right for you and your application.
Essential, Advanced, & Expert Megger Insulation Testers
There are three degrees of functionality within Megger’s MIT & S1 range of insulation testers.
Essential
These models perform all the common tests engineers and technicians are likely to require; though equipped with a comprehensive testing capability, comparatively, Essential models offer the least functionality.
Advanced
Insulation testers in this category provide additional functionality for more demanding applications.
Expert
Megger’s Expert insulation and resistance testers deliver the greatest performance and versatility; they offer the most functionality.
Megger NEW MIT & S1 Insulation Resistance Tester
Megger MIT Insulation Resistance Tester, Essential Range (MIT515/2 & MIT1015)
Megger MIT Insulation Resistance Tester, Advanced Range (MIT525/2, MIT1025/2 & MIT1525/2)
Megger S1 Insulation Resistance Tester, Expert Range (S1-568/2, S1-1068/2 & S1-1568/2)
Essential, Advanced, & Expert Megger MIT & S1 Insulation Testers
| Essential Models | Advanced Models | Expert Models |
| MIT515/2 | MIT525/2 | S1-568/2 |
| MIT1015 | MIT1025/2 | S1-1068/2 |
| MIT1525/2 | S1-1568/2 |
Which Megger Insulation Resistance Tester is Right for You?
In addition to differing tests, Megger’s MIT & S1 Insulation Resistance Testers vary regarding their functions, data storage, communication interfaces, and compatible software. This allows you to choose a model according to your testing, analysis, and reporting requirements, ensuring you purchase the insulation tester perfect for your application, without overspending on capabilities you don’t need.
Megger details the differences between the new MIT & S1 Insulation Resistance Testers in the following table.
Which NEW Megger Insulation Resistance Tester Should You Choose?
Despite the above information, it can still be challenging to determine which Megger insulation tester is best for your industry and job. Helpfully, Megger has outlined the first and second choice testers recommended for a range of applications across various industries. (Please note that this table is not exhaustive.)
| Industry | First Choice | Second Choice |
| Power Utilities | ||
| Distribution - for commissioning and testing after a repair | Advanced | Essential |
| Distribution - for maintenance | Advanced | Essential |
| Transmission - for commissioning and testing after a repair | Expert | Advanced |
| Transmission - for maintenance | Expert | Advanced |
| Industrial | ||
| HV motor testing | Advanced | Essential |
| Maintenance | Advanced | Essential |
| Railway | ||
| Traction motor testing | Advanced | Essential |
| Third-rail power system testing | Advanced | Essential |
| Production/Manufacturing | ||
| Cable manufacturers | Advanced | Expert |
| Production testing | Advanced | Expert |
What’s NEW with the Megger MIT & S1 Insulation Resistance Testers?
Megger’s Mark 2 MIT and S1 models deliver enhanced performance. To this end, Megger has introduced a range of new features that improve ease-of-use, increase efficiency, and widen the instruments’ scope for use.
What’s NEW on ALL Megger’s MIT & S1 Insulation Testers?
Megger NEW MIT & S1 Insulation Resistance Tester
Megger MIT Insulation Resistance Tester, Essential Range (MIT515/2 & MIT1015)
Megger MIT Insulation Resistance Tester, Advanced Range (MIT525/2, MIT1025/2 & MIT1525/2)
Megger S1 Insulation Resistance Tester, Expert Range (S1-568/2, S1-1068/2 & S1-1568/2)
- Colour Display: the new display is easier to read in direct sunlight and makes the insulation testers more intuitive to operate.
- PI Predictor: this patented feature, which has long been available on Megger’s S1 models, has been installed across the range. It makes PI tests, used to assess the insulation health of motors, up to 50% quicker.
- Negative Test Current Handling: prevents momentary negative currents from impacting accuracy.
- Re<Act Mode: a completely new test mode, unique to Megger, the Reabsorption Current Test (Re<Act Mode) could revolutionise DC insulation testing. It ensures measurement accuracy, stops insulation tests from being incorrectly passed or failed, and helps to prevent leaving insulation with a dangerous return voltage.
- Hazardous Peak Voltage Detection: offering additional protection during insulation tests, this function will switch the insulation test off and warn the user not to touch the MIT/S1 Tester when the voltage on the terminals is higher than the instrument’s insulation level.
Find Out More About the NEW Megger ESSENTIAL Insulation Testers
What’s NEW on Megger’s ADVANCED MIT & S1 Insulation Testers?
- Burn Mode Current: selectable 3mA and 6mA (when mains powered) currents burn faults in cables, making it easier to determine the fault location using a time-domain reflectometer (TDR).
- Test/Charge Current: set to 3mA as default, users can choose between this current, 1mA or 6mA (when mains powered). 1mA current limits damage from insulation breakdown and reduces the impact of electric shock, should the user accidentally make contact with a live connection. 6mA current decreases charging time when testing assets with high capacitance, such as long cables.
- Noise Immunity: now increased to 6mA, users can take stable measurements in low-voltage, medium-voltage, and high-voltage environments up to 230kV.
- PDC test: though not entirely new, this test now features a new switch position. PDC is used for specialised insulation testing on motors. Polarisation/Depolarisation Current (PDC) testing is similar to performing DAR, PI, and DD tests all in one.
- Bluetooth Connectivity: wirelessly connect and transfer data to Megger’s CerSuite Asset or PowerDB, as well as iOS/Android smart devices.
Discover the NEW Megger ADVANCED Insulation Testers
What’s NEW on Megger’s EXPERT MIT & S1 Insulation Testers?
- Test/Charge Current: set to 6mA as default, users can choose between this current or 1, 2, 3, 4, and 5mA. Lower currents can limit damage from insulation breakdown and reduce the impact of electric shock, should the user accidentally make contact with a live connection. Higher currents decrease charging time when testing assets with high capacitance, such as long cables.
- Noise Immunity: set to 8mA, this feature has been improved with the introduction of adaptive software filters. These filters complement the averaging, hardware filters also present on the Essential and Advanced models. Combined hardware (averaging) and software (adaptive) filters ensure stable measurements, even in extreme low-voltage, medium-voltage, and high-voltage environments up to 1000kV.
- PDC test: though not entirely new, this test now features a new switch position. PDC is used for specialised insulation testing on motors. Polarisation/Depolarisation Current (PDC) testing is similar to performing DAR, PI, and DD tests all in one.
- Bluetooth Connectivity: wirelessly connect and transfer data to Megger’s CerSuite Asset or PowerDB, as well as iOS/Android smart devices.
Uncover the NEW Megger EXPERT Insulation Testers
Further Information
For additional help or advice regarding Megger’s Mark 2 MIT & S1 Insulation Testers, please contact our Sales team on 01642 931 329 or via our online form.
In the meantime, you can find more information about all these models on our website, tester.co.uk, where you can also browse our complete range of Megger instruments, including insulation resistance testers.
