High Voltage Insulation Resistance Tester: Professional 5kV to 15kV Testing with PI, DAR, Ramp and Step Functions

When Standard Megohmmeters Are Not Enough

While standard insulation resistance meters with test voltages up to 5000V serve most routine maintenance needs, high voltage electrical assets such as power transformers, large generators, high voltage cables, and switchgear often require dedicated high voltage insulation resistance testers. These professional instruments deliver test voltages from 5kV to 15kV with measurement ranges extending to tens of teraohms, along with advanced diagnostic functions that reveal insulation condition details invisible to simpler instruments.

EK Instruments offers three tiers of high voltage insulation resistance testers: the EK-C349 series for essential high voltage testing, the EK-C350 series with touchscreen and advanced functions, and the flagship EK-C352 series with the most comprehensive diagnostic capability available in a portable instrument.

Essential High Voltage Testing: EK-C349 Series

The EK-C349 delivers 5kV test voltage with a 5 teraohm measurement range and 5mA output current. It measures insulation resistance, polarization index (PI), and dielectric absorption ratio (DAR), plus AC voltage for safety verification. With lithium battery power, USB interface, Bluetooth connectivity, 600-group data storage, and a waterproof carrying case, the EK-C349 is built for demanding field conditions.

The EK-C349B doubles the capability with 10kV test voltage and 10 teraohm range, addressing the testing requirements of higher voltage class equipment. Both models provide the core diagnostic functions needed for transformer, generator, and cable insulation assessment in utility and industrial environments.

Advanced Touchscreen Testers: EK-C350 Series

The EK-C350 elevates the testing experience with a 5-inch touchscreen color display that provides intuitive operation and clear data visualization. Beyond standard insulation resistance, PI, and DAR measurement, the EK-C350 adds ramp voltage testing and step voltage testing functions.

Ramp testing applies a continuously increasing voltage while monitoring insulation resistance, revealing voltage-dependent insulation weaknesses that constant-voltage tests may miss. Step testing applies voltage in discrete increments, allowing detailed analysis of insulation behavior at each voltage level. These advanced functions are particularly valuable for evaluating the condition of high voltage cable insulation and transformer winding insulation.

The EK-C350 (5kV, 5 teraohm) and EK-C350B (10kV, 10 teraohm) both feature user-selectable test voltages, lithium battery power, USB, and Bluetooth connectivity with national grid protocol support for standardized data management.

Flagship Diagnostic Platform: EK-C352 Series

The EK-C352 series represents the most comprehensive portable insulation diagnostic platform available. In addition to all functions of the C350 series (insulation resistance, PI, DAR, ramp, and step), the C352 adds dielectric discharge (DD) testing, voltage measurement, and capacitance (CAP) measurement.

Dielectric discharge testing measures the charge released from insulation after the test voltage is removed. The DD index provides a unique diagnostic parameter that can differentiate between different types of insulation degradation, such as thermal aging, moisture contamination, and partial discharge damage. This capability is especially valuable for assessing oil-paper insulation in power transformers.

The EK-C352 (5kV, 10 teraohm, 7mA), EK-C352B (10kV, 20 teraohm, 7mA), and EK-C352C (15kV, 30 teraohm, 7mA) offer progressively higher test voltages and measurement ranges. All three models feature the 5-inch touchscreen, user-selectable test voltages, lithium battery, USB, Bluetooth, and national grid protocol support.

Selecting the Right High Voltage Tester

For routine high voltage insulation testing with essential diagnostic functions, the EK-C349 series provides reliable PI and DAR measurement in a robust field instrument. When advanced voltage-dependent testing (ramp and step functions) is needed along with a touchscreen interface, the EK-C350 series offers the optimal balance of capability and value.

For the most thorough insulation diagnostics including dielectric discharge analysis and capacitance measurement, the EK-C352 series provides the complete diagnostic toolkit. The 15kV EK-C352C is specifically designed for extra-high voltage applications where maximum test voltage and measurement range are essential.