Sonel Insulation Resistance Testing: MIC-5050, MIC-10K1 & MIC-2511
ProgUSA supplies the Sonel MIC series of insulation resistance testers with U.S.-based support, training, and service. ProgUSA has supplied electrical test and measurement equipment to utilities, NETA firms, and industrial users since 2005.
The MIC series covers diagnostic insulation resistance testing across utility and industrial assets, from a portable 2.5 kV field tester to 5 kV and 10 kV instruments built for substation environments.
Why Insulation Resistance Testing Matters
Insulation is what separates energized conductors from ground and from each other, and it degrades over time through heat, moisture, contamination, and mechanical stress. Measuring insulation resistance is one of the most direct ways to catch that degradation before it becomes a fault.
Tracking insulation resistance over the life of a motor, cable, or transformer gives crews an early, trendable indicator of condition, supporting repair-versus-replace decisions long before insulation fails in service.
MIC-5050
The MIC-5050 is the core of the line, a 5 kV insulation resistance meter that measures up to 20 TΩ. Test voltage is adjustable across a wide range, and a highly efficient HV inverter delivers a stable output for demanding measurements.
Its three-wire measurement, using a dedicated GUARD lead, eliminates surface leakage currents caused by contaminated insulation, improving the reliability of results. Built-in digital filters keep readings stable in high-interference environments, and the meter is rated to work where strong electromagnetic disturbances are present, such as EHV substations. An onboard graphical screen plots resistance, voltage, and current over time so crews can assess insulation condition as the test runs.
MIC-10K1 and MIC-2511
The MIC-10K1 extends the same diagnostic capability to a 10 kV test voltage for higher-voltage apparatus and the most demanding insulation systems, while sharing the MIC-5050's measurement approach and feature set.
The MIC-2511 is a 2.5 kV insulation resistance meter for lower-voltage work, a compact, field-friendly option for routine testing where the higher output of the 5 kV and 10 kV units isn't required. Together the three models let utilities standardize on one instrument family across voltage classes.
Insulation Diagnostics
Beyond a single resistance reading, the MIC series supports time-based diagnostics that reveal how insulation behaves under sustained voltage. These include the Polarization Index (PI) and Dielectric Absorption Ratio (DAR), which compare readings taken at set intervals, and Step Voltage (SV) testing, which applies voltage incrementally to expose defects that a single-voltage test would miss. The instruments also measure object temperature to support temperature-corrected resistance values.
Applications
Utilities and service providers use the MIC series to assess the insulation condition of motors and generators, single- and multi-core cables, transformers, capacitors, switchgear, and other apparatus installed in power stations, across commissioning, routine maintenance, and troubleshooting.
ProgUSA Support
ProgUSA supplies Sonel insulation resistance testers with U.S.-based support, training, and service.
Equipment Selection
We help utilities match the right MIC model to their voltage class and testing program.
Training
We provide training on test procedures, diagnostics, and result interpretation.
Calibration and Repair
Calibration and repair for Sonel instruments are coordinated through ProgUSA.
Demonstrations
On-site demonstrations let crews evaluate the MIC series with their own equipment.
Learn More
The Sonel MIC series is available through ProgUSA, listed under HiPot & Substation Test Equipment.
Request a quote or demonstration →
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