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Hioki IR4057-20 Digital Meg-Ohm Insulation Tester

Hioki IR4057-20
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Digital Meg-Ohm Meter


  • 5-range testing voltage 50 V/100 MΩ to 1000 V/4000 MΩ
  • Stable & medium-speed digital readings, response time at PASS/ FAIL decision 0.8 second
  • Drop proof onto concrete from 1m (3.28 feet)
  • Bright LED luminous LCD, Test lead with bright LED lamp to illuminate near hand (Option L9788-11 or L9788-10)
  • Continuity check via 200 mA testing
  • Built in AC/DC voltage meter, useful for testing solar power generation systems and electric vehicles
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Sale: $499.00
  + Free shipping over $99

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Product Name Type IR Test Voltage Maximum Insulation Resistance Availability Price  
Digital Meg-Ohm Meter
Battery 1,000 V, 125V, 250 V, 50 V, 500 V 4 G Ohms Availability
in stock!
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Analog Meg-ohm Meter (replacing 3451-13)
Battery 500 V 100 M Ohms (0.1 G Ohms) Availability
in stock!
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Analog Meg-ohm Meter (replacing 3451-14)
Battery 500 V 1 G Ohms Availability
in stock!
Edu Price Standard Price Gov't Price
Analog Meg-ohm Meter (replacing 3451-15)
Battery 1,000 V 2 G Ohms Availability
in stock!
Edu Price Standard Price Gov't Price
Analog Meg-ohm Meter
Battery 1,000 V, 250 V, 500 V 4 G Ohms Availability
in stock!
Edu Price Standard Price Gov't Price
Digital Meg-Ohm Meter
Battery 1,000 V, 125V, 250 V, 50 V, 500 V 4 G Ohms Availability
in stock!
Edu Price Standard Price Gov't Price
High Voltage Insulation Tester
Battery 1,000 V, 2,500 V, 250 V, 5,000 V, 500 V 5 T Ohms (5000 G Ohms) Availability
in stock!
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Product Information

Hioki IR4057-20 Digital Meg-Ohm Meter Insulation Tester

Comparator function provides PASS/FAIL decisions at a glance

  • The comparator function compares measured values to pre-set reference values to generate a pass or fail judgment. (Can be used with insulation resistance measurement and low-resistance measurement.)

  • The stable display is easy to read, increasing work efficiency.

Instant judgment
Since the IR4056-20 and IR4057-20 generate judgments as soon as the test lead makes contact, it is possible to make a rapid series of measurements in the manner of a continuity check.
Identify PASS/FAIL using light and sound
The IR4056-20 and IR4057-20 notify the operator of pass and fail judgments using a beeping sound, LCD light, and comparator indicator on the test lead with remote control switch (optional accessory), allowing determinations of compliance to be made without looking at the instrument.
When the measured value is greater than or equal to the reference value*
Short beep
Pass Green
  No change Green
When the measured value is less than the reference value*
Continuous tone
Fail Red
*Insulation resistance measurement Red Red

Designed for safety and peace of mind

Featuring improved convenience and ease of use
Drop-Proof DROP PROOF Testers are built tough to withstand a 1-meter drop onto a concrete floor
AC/DC voltage measurement (With AC/DC automatic detection function) Use as a tester replacement thanks to DC voltage measurement functionality, which is useful in applications involving solar power and electric vehicles (EVs).
200 mA grounding line continuity check function The IR4056-20 and IR4057-20 can perform EV and HEV continuity checks as well as resistance measurement of safety conductors in building electrical equipment as defined by IEC 60364.
Intergrated-Hard-Case Integrated hard case with sliding cover
Test-Lead-L9787 TEST LEAD L9787 Connect either the test probe or alligator clip for the earth side
Easy-to-see LCD An FSTN LCD ensures the instrument's display is easy to read from any angle.
Effective maximum display value A ">" mark is displayed when the measured value is greater than the effective maximum display value for the function in use.
Backlight Backlight (White LED) A backlight makes it possible to work in dark or poorly lit locations.
Safety-oriented double-action
500 V/1000 V range only
Safety-Oriented Set the function key to either 500 V or 1000 V. Double-Action Press the flashing “RELEASE” key.


     Economical Model


Bar graph for visual judgments
High-speed model
5 ranges
50/125/250/500/ 1000 V
Rated output voltage (DC) 5 ranges
50/125/250/500/ 1000 V
Voltage measurement
Resistance measurement
Approx. 0.8 s Comparator judgement result response time Approx. 0.3 s
200 mA continuity
- Bar graph
159W x 177H x 53D Dimensions(mm) 159W x 177H x 53D
600 Mass(g) 640
Bar graph Useful in determining compliance of circuits with a large capacitance component, for example solar panels, due to the ability to illustrate charging status behavior.

The Hioki IR4057-20 Digital Multimeter and Insulation Resistance Tester offers an insulation resistance test at 50V, 125V, 250V, 500V and 1000V DC with an insulation resistance scale of 0...4000MΩ. This meter also includes Voltage measurements with a 0V...750V range and a resistance measurement range of 0Ω...1000Ω. This meter also come with a high speed comparator function that alerts the user to failed tests with a buzzer and red LED.

The comparator compares measured values to pre-set reference values to make pass/fail decisions. Thanks to improved response performance, the Hioki IR4056-20 Insulation Tester provides an instantaneous pass/fail decision when the test lead is placed in contact with a target.

Furthermore, the comparator function allows operators to assess pass/fail decisions based on light and sound cues. “Pass” conditions are signaled by a short beeping sound and a green LED, while “fail” conditions are signaled by a longer, continuous tone and a red-backlit measurement screen. When used with the optional Test Lead with Remote Control Switch L9788-11, the “fail” condition can also be easily identified by the lead’s red LED.

It is not unusual for technicians to need to measure more than 100 locations in a single building, so the instruments’ ability to generate a continuous series of pass/fail decisions will yield significant improvements in work efficiency.

Most measurement targets consist of long cables that have already been laid in a facility. Consequently, insulation resistance readings are often unstable due to the effects of noise emitted by nearby electrical wiring and other sources of interference. The Hioki IR4056-20 Insulation Tester employes a variety of measures to stabilize the display of readings so that it is easy to read measured values, even in challenging environments.

The Hioki IR4056-20 Insulation Tester provides functionality for generating high-voltage 500V and 1,000V output when testing high-voltage equipment. Normally, inadvertent application of a high voltage to a low-voltage device can damage the device. To protect against this risk, the new instruments provide functionality for preventing the application of unintentional high-voltage output

Outputting 500V or 1,000V requires two steps: placing the function key in a certain position and then pressing a flashing key to cancel the high-voltage output lock feature. In this way, the instruments are designed to prevent inadvertent output due to mistaken function key operation.

There is growing need for instruments capable of DC voltage measurement due to increasingly widespread use of solar power and electric vehicles. As a result, HIOKI designed the Hioki IR4056-20 Insulation Tester with both AC and DC voltage measurement functionality.

In addition to low-resistance measurement at 200 mA DC, the Hioki IR405620 Insulation Tester support JIS C 60364-compliant insulation measurement of safety conductors in building electrical equipment and indirect safety contact testing in electric and hybrid vehicles.

What's In The Box

  • 1 - Test Lead L9787
  • 1 - Neck Strap
  • 1 - Instruction manual
  • 4 - LR6(AA) alkaline batteries


Economic model
Bar graph for visual judgments Economic model High-speed model
5 ranges
50/125/250/500/ 1000 V
Approx. 0.8 s Approx. 0.3 s
159W×177H×53D 159W×177H×53D
600 640
Rated output voltage (DC)
Resistance measurement
Comparator judgment result response time
200 mA continuity
Bar graph
Voltage measurement
Rated output voltage (DC) 50V 125V 250V 500V 1000V
Effective maximum indicated value 100 MΩ 250 MΩ 500 MΩ 2000 MΩ 4000 MΩ
Effective medium value 2 MΩ 5 MΩ 10 MΩ 50 MΩ 100 MΩ
1st effective measuring range [MΩ] 0.200 to 10.00 0.200 to 25.0 0.200 to 50.0 0.200 to 500 0.200 to 1000
Accuracy ±4 % rdg
2st effective measuring range [MΩ] 10.1 to 100.0 25.1 to 250 50.1 to 500 501 to 2000 1010 to 4000
Accuracy ±8 % rdg
Ωther measuring range [MΩ] 0 to 0.199
Accuracy ±2 % rdg. ±6 dgt.
Lower limit resistance value to maintain nominal output voltage 0.05 MΩ 0.125 MΩ 0.25 MΩ 0.5 MΩ 1 MΩ
Ωverload protection 600 VAC (10 s) 1200 VAC (10 s)
Indicator Indicator: Semi-transmissive FSTN LCD, positive Backlight
Functions Live circuit indicator, Automatic electric discharge, Automatic DC/AC detection, Comparator, Built-in battery power indicator etc.
IR4057-20 Functions Bar graph, Displaying 1-min. Values
Power source LR6 alkaline battery × 4
Continuous operating time Approx. 20 hours
(Comparator off, backlight off, 500 V range, no load)
Auto Power Save The power will go off automatically 10 minutes after the last operation.
Ωperating temperature and humidity 0 to 40°C (32 to 104°F)
90% RH or lower (non-condensating)
Storage temperature and humidity -10 to 50°C (14 to 122°F)
90% RH or lower (non-condensating)
Maximum rated voltage to earth 600 V AC/DC, Measurement Category,
Anticipated Transient Ωvervoltage: 6000 V
Dielectric strength 7060 V AC, 50/60 Hz, Measurement terminals - electrical enclosure, 1 min, current sensitivity 1 mA
Degree of protection IP40
Standards EN61326 (EMC), EN61557-1/ -2/ -4*/ -10
Drop proof Ωn concrete: 1 m
Dimensions Approx. 159W×177H×53D mm
(6.26"W×6.97"H×2.09"D) (excluding protrusions)
Mass IR4056-20: Approx. 600g (21.2 oz)
IR4057-20: Approx. 640g (22.6 oz)
(including battery, excluding test lead)
Accessories Test Lead L9787 × 1, Neck strap × 1, Instruction manual × 1, LR6 alkaline battery × 4
Display range
(Auto range)
4.2 V 42 V 420 V 600 V
Maximum indicated value 4.200 V 42.00 V 420.0 V 750 V
Resolution 0.001 V 0.01 V 0.1 V 1 V
Accuracy ±1.3 % rdg. ±4 dgt. *
Display range
(Auto range)
420 V
(Minimum indicated value: 30.0 V)
600 V
Maximum indicated value 420.0 V 750 V
Resolution 0.1 V 1 V
Accuracy ±2.3 % rdg. ±8 dgt. *
Measurement Principles Average responding type
Frequency range 50/60 Hz
AC/DC automatic detection range AC detected at 30 V or greater (50/60 Hz) (Pulsating currents with an overlapping AC component of 30 V or greater are detected as AC)
Effect of temperature Measurement accuracy per 1°C × 0.1 (Applicable to the operating temperature range other than 18 to 28°C)
Display range
(Auto range)
10 Ω 100 Ω 1000 Ω
Maximum indicated value 10.00 W 100.0 W 1000 W
Resolution 0.01 W 0.1 W 1 W
(after zero adjustment)
0 to 0.19 W: ±3dgt.
0.20 to 10.00 Ω: ±3%rdg. ±2dgt.
±3%rdg. ±2dgt.
Measuring current 200 mA or more (at 6 Ω or less )
(Display value before zero adjustment)
Ωverload protection 600 VAC (10s, using Fuse)

Hioki IR4057-20 Product Specifications Summary:
(for full specs please see the full specs tab or the data sheet)

Micro / Milli / Meg Ohmmeters/Megohmmeter / Insulation Resistance Testers Template

Type What's This?Battery
IR Test Voltage What's This?1,000 V, 125V, 250 V, 50 V, 500 V
Maximum Insulation Resistance What's This?4 G Ohms
Minimum Insulation Resistance0.2 Ohms (0.0000000002 G Ohms)
Variable Incremental Voltage What's This?No
Display (Megohmmeter) What's This?Digital 
Continuity TestYes
Live Circuit Voltage Detection What's This?No
Power SupplyBattery
CAT Rating What's This?III
CAT Voltage What's This?600 V

Test Equipment General Attributes

Unique FeaturesBar Graph display for determining compliance of circuits with a large capacitance component
Comparator function for easy Pass/Fail judgement
Drop Proof to 1M
White LED Backlight
Integrated hard case with sliding cover
Warranty2 YEARS
Calibration IncludedNone
Power Supply VoltageBattery Powered
Safety ApprovalCE
Data Logging What's This?No
IP Rating What's This?IP40
Battery TypeAA 
Product Height6.97 IN
Product Length6.26 IN
Product Width2.09 IN
Country of OriginJapan


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