HIOKI IR4056-21 Digital Insulation Resistance Tester | 50V-1000V High-Speed CAT III 600V
Brand: Hioki
HIOKI IR4056-21 Digital Insulation Resistance Tester — High-Speed, Field-Ready, Made in Japan
The HIOKI IR4056-21 is a 5-range, 50V to 1000V digital insulation resistance tester built with efficient functions to help shorten field testing time. As the high-speed measurement variant of the IR4056 series, it comes standard with the L9788-11 test lead set with remote switch, allowing technicians to measure and verify pass/fail results without needing to look directly at the instrument.
Like all HIOKI insulation testers, it is designed and manufactured in Japan at HIOKI's own facilities in Nagano Prefecture.
Key Specifications
| Specification | Details |
|---|---|
| Model | HIOKI IR4056-21 |
| Measurement Type | High-Speed |
| Number of Ranges | 5 |
| Test Voltages | 50V / 125V / 250V / 500V / 1000V |
| Max Insulation Resistance | Up to 4000MΩ |
| DC Voltage Measurement | 600V |
| AC Voltage Measurement | 600V |
| Safety Category | CAT III 600V |
| Comparator Response Time | 0.3 second |
| Dustproof/Waterproof Rating | IP40 |
| Drop Tested | 1 metre onto concrete |
| Dimensions (W×H×D) | 159 x 177 x 53mm |
| Weight | Approx. 640g |
| Power Supply | LR03 (AAA) alkaline battery x 4 |
| Continuous Operating Time | Approx. 20 hours |
| CE Marking | Standard model — not CE marked (CE version available separately) |
| Brand | HIOKI |
| Origin | Japan |
Key Features
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5-range testing voltage of 50 V/100 MΩ to 1000 V/4000 MΩ
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Stable & medium-speed digital readings, 0.8 second response time of PASS/ FAIL decisions
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Drop proof onto concrete from 1m (3.28 feet)
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Bright LED, luminous LCD, test lead with bright LED lamp to illuminate near hand (Also available in the IR4056-21)
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Continuity check via 200 mA testing
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Built in AC/DC voltage meter, useful for testing solar power generation systems and electric vehicles


Model No. (Order Code)
| IR4056-20 | Economic model |
|---|---|
| IR4056-21 | Economic model, Not CE marked |
| Rated output voltage | 50 V DC | 125 V DC | 250 V DC | 500 V DC | 1000 V DC | |
|---|---|---|---|---|---|---|
| Effective maximum indicated value | 100 MΩ | 250 MΩ | 500 MΩ | 2000 MΩ | 4000 MΩ | |
| Accuracy 1st effective measuring range MΩ |
±2 % rdg. ±2 dgt. 0.200 - 10.00 |
±2 % rdg. ±2 dgt. 0.200 - 25.0 |
±2 % rdg. ±2 dgt. 0.200 - 50.0 |
±2 % rdg. ±2 dgt. 0.200 - 500 |
±2 % rdg. ±2 dgt. 0.200 - 1000 |
|
| Lower limit resistance | 0.05 MΩ | 0.125 MΩ | 0.25 MΩ | 0.5 MΩ | 1 MΩ | |
| Overload protection | 600 V AC (10s) | 660 V AC (10s) | ||||
| DC voltage range |
4.2 V (0.001 V resolution) to 600 V (1 V resolution), 4 ranges, Accuracy: ±1.3 % rdg. ±4 dgt., Input resistance: 100 kΩ or higher |
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| AC voltage range |
420 V (0.1 V resolution) / 600 V (1 V resolution), 2 ranges, 50/60 Hz, Accuracy: ±2.3% rdg. ±8 dgt., Input resistance: 100 kΩ or higher, Average rectifier |
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| Low resistance range |
For checking the continuity of ground wiring, 10 Ω (0.01 Ω resolution) to 1000 Ω (1 Ω resolution), 3 ranges, Basic accuracy: ±3 % rdg. ±2 dgt., testing current 200 mA or more (at 6 Ω or less) |
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| Display | Semi-transmissive FSTN LCD with back lighting, bar-graph indicator | |||||
| Response time | Approx. 0.8 second for PASS/FAIL decision (based on in-house testing) | |||||
| Other functions |
Live circuit indicator, Automatic electric discharge, Automatic DC/AC detection, Comparator, Drop proof, Auto power save |
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| Power supply |
LR6 (AA) alkaline batteries ×4, Continuous use: 20 hours (Comparator off, backlight off, 500 V range, no load)
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| Dimensions and mass | 159 mm (W) × 177 mm (H) × 53 mm (D), 600 g (21.2 oz) (including batteries, excluding test leads) |
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| Accessories |
[IR4056-20] Test lead L9787 ×1, Neck strap ×1, Instruction manual ×1, LR6 (AA) alkaline batteries ×4
Neck strap ×1, Instruction manual ×1, LR6 (AA) alkaline batteries ×4 |
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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
- Solar power generation system testing
- Electric vehicle (EV) and hybrid vehicle (HEV) testing
Why Choose HIOKI IR4056-21?
- High-speed measurement with standard remote switch test lead
- 5-range testing from 50V to 1000V
- Insulation resistance measurement up to 4000MΩ
- Pass/fail comparator with light and sound indication
- Built-in AC/DC voltage meter for pre-test safety checks
- Drop tested to 1 metre — built for field durability
- CAT III 600V safety rated
- Trusted HIOKI professional instrument quality — Made in Japan
Inquiry - HIOKI IR4056-21 Digital Insulation Resistance Tester | 50V-1000V High-Speed CAT III 600V