L9788-11 - Remote Switch Lead Set for HIOKI Insulation Testers

Digital insulation tester with Bluetooth® and five test ranges (50–1000 V) for fast, accurate measurements in lab and industrial environments. Order now from HIOKI Europe.

Digital insulation tester with Bluetooth and bar graph for measurements from 50 V to 1000 V in installation and maintenance testing. HIOKI IR4057-90 available now.

Key Specifications5 test voltages from 50 V to 1000 V Insulation resistance up to 4000 MΩSafety category CAT III 600 V Digital bar graph display200 mA protective conductor test in accordance with EN 61557-4 Typical Applications Inspection and maintenance of low-voltage electrical installations Troubleshooting insulation faults in wiring, motors, and equipment Field testing of machinery, control panels, and distribution boards Periodic inspection of plant and equipment Feature IR4053 IR4056 IR4057-50 IR4057-90 IR4059 PVΩ Function Yes – Bar Graph Display – Yes Bluetooth – Optional (Z3210) Yes (Z3210 included) Optional (Z3210) Housing Integrated hard case Compact housing with silicone protector L9788-10 Test Lead with Remote Switch Optional Yes Detailed Product OverviewIn installation and maintenance work, insulation resistance testing is required when checking wiring, distribution boards, motors and electrical equipment after repairs or during periodic inspections. A dedicated insulation tester is often the practical choice without the need for a multifunction installation tester or combined test instrument. The IR4057-50 is a digital, battery-powered insulation tester with five test voltages from 50 V to 1000 V. It measures insulation resistance up to 4000 MΩ and is used for testing electrical installations, motors, machinery and control systems. The instrument complies with EN 61557 requirements for insulation resistance and protective conductor continuity testing in low-voltage installations.Digital Bar Graph and Fast PASS/FAIL Evaluation In addition to the numeric display, the IR4057-50 features a digital bar graph that provides immediate visual indication of insulation resistance during measurement. Changes in resistance are visible directly on the scale display. The integrated comparator evaluates the insulation measurement in approximately 0.3 seconds and indicates PASS or FAIL. PASS and FAIL are signaled acoustically, and in the event of a FAIL result, the display backlight turns red. The PASS/FAIL threshold can be set individually for each test voltage range and remains stored even after switching the instrument off or changing the range. With the comparator function switched off, the instrument instead displays the insulation resistance value after 60 seconds during an ongoing measurement. This supports time-based evaluation when longer test durations are required. Protective Conductor (PE) and Voltage CheckProtective conductor testing is performed with a 200 mA test current in accordance with EN 61557-4. The defined test current applies sufficient load to the protective conductor connection to detect increased contact resistance, loose connections and oxidized terminals. This provides a more reliable assessment than a low-current continuity check performed with a standard digital multimeter.In addition to insulation and low-resistance measurement, the instrument includes AC and DC voltage testing up to 600 V. This allows verification that the test object is not live before starting an insulation measurement. For added safety, the 500 V and 1000 V test voltages must be manually unlocked before the first measurement. This prevents accidental activation of higher test voltage levels. For Daily Field Work The IR4057-50 complies with CAT III 600 V and has been tested for a 1 m drop onto concrete. It is specified for operation in ambient temperatures from -25 °C to 65 °C. The instrument is integrated into a robust hard case that forms a single protective unit and provides storage space for test leads and accessories. The leads remain connected during transport, allowing the tester to be stored and carried as one complete unit.The display offers high contrast and includes a backlight for work in distribution boards and poorly lit technical rooms. With the optional Z3210 wireless adapter, measured values can be transferred via Bluetooth to the free GENNECT Cross app on iOS or Android devices. An optional L9788-10 test lead with integrated LED illumination and measurement trigger allows measurements to be started directly from the probe.Like all HIOKI insulation testers, it is designed and made in Japan at HIOKI’s own factories in Nagano Prefecture.

The HIOKI IR4056 is a digital insulation resistance tester with efficient functions and features to help shorten work time associated with field insulation testing.

Key SpecificationsPVΩ function for live PV strings50 V to 1000 V test voltagesInsulation resistance measurement up to 4000 MΩ AC/DC voltage measurement up to 600 V CAT III 600 V Typical ApplicationsInsulation testing of PV strings under DC voltageVerification of open-circuit voltage and polarity of PV stringsTesting of low-voltage installationsMaintenance and troubleshooting of electrical systems Feature IR4053 IR4056 IR4057-50 IR4057-90 IR4059 PVΩ Function Yes – Bar Graph Display – Yes Bluetooth – Optional (Z3210) Yes (Z3210 included) Optional (Z3210) Housing Integrated hard case Compact housing with silicone protector L9788-10 Test Lead with Remote Switch Optional Yes Detailed Product OverviewInsulation resistance testing of PV systems is often carried out during daytime service work. PV strings generate DC voltage as long as they are exposed to light, even when the inverter is switched off. Standard insulation or installation testers will not start the test if external voltage is detected. The IR4053 includes a PVΩ function that allows insulation testing of PV strings even when DC voltage is present. The instrument measures the existing string voltage and takes it into account during the test. The displayed insulation value is based only on the applied test voltage.Full Insulation Tester for Low-Voltage Systems The IR4053 is a battery-powered insulation tester for low-voltage installations and is used for standard insulation testing of distribution boards, motors, cables and electrical equipment in addition to PV measurements. The instrument provides five selectable test voltages from 50 V to 1000 V and measures insulation resistance up to 4000 MΩ. It also measures AC and DC voltage up to 600 V. When measuring DC voltage, reversed polarity is clearly indicated. This supports verification of open-circuit voltage and correct polarity of PV strings before commissioning or maintenance. Fast PASS/FAIL EvaluationFor routine testing, the IR4053 includes an integrated comparator function. The measured insulation value is automatically evaluated against a user-defined threshold and indicated as PASS or FAIL. The threshold can be set individually for each test voltage. The settings remain stored even after the instrument is switched off. An acoustic signal supports quick assessment during measurement. Designed for Everyday Use The IR4053 complies with CAT III 600 V and has been tested for a 1 m drop. An integrated hard case forms a single unit with the instrument and provides storage space for test leads and accessories. The leads remain connected to the tester during transport. The display offers high contrast for clear readability under varying lighting conditions. An integrated backlight supports measurements in poorly lit distribution boards and technical cabinets. An optional L9788-10 test lead with built-in LED illumination and remote measurement trigger is available. Measurements can be initiated directly from the probe, which is useful when both hands are needed to secure the test leads on the test object. The IR4053 supports insulation test voltages up to 1000 V and is suitable for PV strings and low-voltage systems within this range. For PV systems with higher string voltages up to 2000 V, HIOKI offers the IR5051 high voltage insulation tester. Like all HIOKI insulation testers, it is designed and manufactured in Japan at HIOKI’s own facilities in Nagano Prefecture.

The L9788-10 is a 1.2 m red test lead with integrated remote switch and LED illumination for selected HIOKI insulation testers. Measurements can be started directly from the probe without returning to the instrument. The LED illumination is switched on and off together with the instrument’s display backlight and supports work in poorly lit distribution boards and technical rooms. With the tip cover attached, the measurement category is CAT III 600 V. Without the tip cover, it is CAT II 600 V. The test lead is compatible with digital insulation testers IR4053, IR4056, IR4057-50, IR4057-90 and IR4059 as well as with the analog models 3490, IR4016, IR4017 and IR4018. It is also suitable for use with the HIOKI FT4310 Bypass Diode Tester. The L9788-10 is included with the IR4059. For the other models, it is available separately as an accessory.

L9788-90 is the spare part tip of the test lead L9788-10. Technical information: Tip length 35 mm Tip diameter: 3.2 mm Color: Red

The L9788-92 is a detachable accessory tip for the L9788-10 test lead for checking breaker terminals.Technical information:Tip length: 121 mm Tip diameter: 2.6 mm Voltage safety categoriy: Cat III 600V Imax: 2 A Color: Red Compatible to: L9788-10, L9788-11