Hioki IR5051 High Voltage Insulation Tester

• Test voltage range: 250 V to 5 kV (5 ranges)
• Insulation resistance: 10 MΩ to 10 TΩ (7 ranges)
• PV test voltage range: 250 V to 2 kV
• PV insulation resistance: 10 MΩ to 100 GΩ
• PV measurement time: approx. 4 s
• Safety rating: CAT III 2000 V
• Enclosure rating: IP65 (with carrying case)
• Battery-powered
• Bluetooth communication via optional Z3210

Applications

• Insulation testing of PV systems up to 2000 V during operation
• Localization of ground faults in PV strings
• Insulation testing of cables, motors and transformers

The Hioki IR5051 is a portable high voltage insulation tester that combines standard insulation resistance measurement with a dedicated PV function for photovoltaic systems. It enables insulation testing of PV systems even during power generation.

The instrument provides five test voltage ranges from 250 V to 5 kV and measures insulation resistance up to 10 TΩ. For PV applications, a physically separate measurement section allows insulation testing up to 2000 V and 100 GΩ. This makes it possible to perform measurements during daytime operation without shutting down the system. Each measurement is completed in approximately 4 seconds, which is beneficial when testing large PV installations.

The compact and robust design is intended for field use in PV systems and other high-voltage environments. The included hard case provides IP65 protection against dust and water. After measurement, the automatic discharge function safely dissipates residual voltage in the test object. Shielded test leads and the built-in guard circuit reduce interference and support stable measurement conditions.

In addition to PV testing, the IR5051 can be used for standard insulation measurements on cables, motors and transformers. Diagnostic functions such as Polarization Index (PI), Dielectric Absorption Ratio (DAR) and Dielectric Discharge (DD) support detailed evaluation of insulation condition over time.

Step Voltage and Ramp tests allow insulation behavior to be assessed under increasing test voltage, helping to identify weak points that may not be visible at a single fixed test voltage.

Measurement data can be stored internally and retrieved later for documentation and analysis. With the optional Z3210 adapter, data can be transferred via Bluetooth to mobile devices and used with the GENNECT Cross app. For PC-based workflows, the optional DT4900-01 communication package provides an optically isolated interface and supports instrument configuration.

The IR5051 is designed and manufactured in Japan at HIOKI’s own production facilities.

What’s Included

• IR5051 High Voltage Insulation Tester
• C0212 carrying case
• L9850-01 red test lead, 3 m
• L9850-02 black test lead, 3 m (shielded)
• L9850-03 blue test lead, 3 m
• L9851-01 red alligator clip (for L9850-01)
• L9851-02 black alligator clip (for L9850-02)
• L9851-03 blue alligator clip (for L9850-03)
• L9852 test pin set (red and black)
• LR6 alkaline batteries ×8
• Instruction manual