The MIT420/2 Megger is an industrial insulation tester with multimeter tendencies. With variable voltage test ranges and up to 200GΩ, it is good for a variety of test scenarios and can accurately measure voltage and resistance as well as perform fast continuity tests. Primarily used to detect motor winding and cable faults by maintenance workers and installers, with results on a dual display.
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- Test range: 50V to 1000V
- Insulation resistance to 200GΩ
- PASS/FAIL indication
- Dual display with arcing bar graph
- Measures AC/DC voltage to 600V
- Measures AC/DC millivolts
- TRMS AC accuracy
- Measures frequency and capacitance
- Combined continuity / voltage
- Current test voltage display
- Dielectric absorption ratio tests
- Reverse continuity testing
- Auto ranging scales
- Memory storage
- Auto power off
- Powered by AA batteries
- Can run on rechargeable batteries
- Category IV safety rated
- IP54 – dust and splash proof
- Size: 8.66″ (220mm) x 3.63″ (92mm) x 1.97″ (50mm)
- Weight: 20.7oz (590g)
- MIT420/2 Megger
- Test leads
- X6 AA batteries
- Large carry case
- Calibration certificate
See here for the MIT400 Series online manuals
Review of the MIT420/2 Megger
This replacement for the Megger MIT420 has a new case with kickstand and extra features. Test ranges on the MIT420/2 are between 50V and 1000V and it boasts a whopping 200GΩ insulation resistance. You can step up in 10V increments to hit specific test voltages across one range to get closer to operating voltage.
Results can be saved and are easy to recall. There’s also a voltage detection test inhibit function, set at 50V, along with quick discharge post-test. In addition are voltage, capacitance and frequency multimeter ranges together with continuity tests.
It is an auto ranging multimeter and even boasts true RMS (TRMS) for the accurate measuring of non-sine AC waves. There’s a single megohms range and the continuity is swift, compared with the previous version at least.
Of ergonomics, it is nicely shaped and easy to hold. It also offers IP54 weatherproofing and separate battery and fuse compartments.
Limits and Polarization: Over-voltage has been limited to 2% during insulation testing on the MIT410/2, where the standard calls for 10%. You can also use this meter to perform polarization index (PI) and dielectric absorption ratio (DAR) tests.
MIT400 Series Basics
Megger have been around for many years and are well known in the UK, where they are headquartered. A premium brand, Megger testers accurately and safely test insulation resistance, with the MIT400 series offering additional features.
The series is a range of industrial insulation testers with multimeter capabilities for industrial usage. They come in handheld or bench type varieties and display in both digital and analog-style format. Good for motor testing, installations, control panels, automotive, avionics, and general maintenance.
There are several meters in the range to include communications and high voltage output (2500V). The below table corresponds to those in this review.
|Model||voltage||PI / DAR||vari voltage||storage||bluetooth|
|MIT400/2||250V – 1000V|
|MIT410/2||50V – 1000V||✓|
|MIT420/2||50V – 1000V||✓||✓||✓|
|MIT430/2||50V – 1000V||✓||✓||✓||✓|
Price: The MIT410/2 is expensive at around $800 but these devices are heavily engineered and the cost is justified. The Fluke 1587FC is similar on specs and price.
|Test (set) voltages||50,100,250,500,1000V|
|Insulation||50-100V / 10-200GΩ||±(2.0%+2) 0.2-4% per GΩ|
|AC voltage||10mV / 600V||±(2.0%+1) @ 15-400Hz|
|DC voltage||0 / 600V||±(2.0%+2)|
|Capacitance||1nF / 10μF||±(5.0%+2)|
|Frequency||15Hz / 400Hz||±(0.5%+1) @ 100-400Hz|
|Continuity||0.01W to 999kW||±(3.0%+2)|
The MIT420/2 Megger Tester is a very rugged and nicely designed insulation tester. It has clean lines and a stylish case, ergonomically designed to aid grip. The meter is edged by a rubber boot and it ships in a handy molded carry case with plenty of room for the meter and leads.
It has a nice interface with quality rotary switch, test button and function buttons. The leads are good quality and ship with crocodile clips that fit atop. There’s also a control probe lead.
The display on the MIT420/2 Megger is large, clear and uncluttered. It has a combined digital / analog layout, with feedback in digits as well as via an arcing bar graph. In addition is a dual display that lets you see both the test voltage and insulation resistance simultaneously. The screen is also backlit, with the timer adjustable to 20 or 60 seconds. Factory setting is 20 seconds and it can be disabled.
Function and Performance
The MIT400 series is a solid product with nice controls and functions. The rotary switch and scales are very clear and there is a variety of functions accessed through the easy buttons, including save and backlight. The Megger MIT420/2 is reactive with results in seconds.
It is supplied with x6 AA batteries and you can also use rechargeable batteries. A battery condition indicator stays on at all times with x5 bars alluding to: 100% charge, 75%, 50%, 25%, and low. Be aware that if you plan on using NiMH rechargeable batteries, the charge level indicator might show a lower level than with standard alkaline batteries.
Auto off: The Megger MIT420/2 is equipped with an auto off sleep timer, which is adjustable to 10, 20, 30, or 60 minutes. It is defaulted to 10 minutes and can be disabled.
Safety rating is to Category IV @ 600V, meaning you can test everything inside the building as well as the power coming in. The IP rating is IP54, which is good for splashes and guarding against dust.
Fuse protection: The meter is protected by a 500mA HRC (high rupture capacity) fuse. For a quick fuse check, a blown fuse indicator will show in the display when continuity range is selected.
Batteries and fuses have separate compartments on the reverse and are accessed by single screws.
Pros and Cons
- Solid brand
- High test ranges
- Variable voltage tests
- Multimeter usage
- Dual display with analog bar graph
- Battery and fuse indicators
- Bespoke leads
The MIT420/2 Megger tester is among one of the best handheld insulation resistance testers around, from a leading manufacturer in its field. Key features are variable voltage tests and a scale up to 200GΩ, and it has a fantastic display and key multimeter ranges. You will pay handsomely for this, but it is very well made and reviewed.
Alternatives: Many compare the Fluke 1587, or Fluke 1587FC, which are similar in price and have more in the way of traditional multimeter ranges. The similarly sized Keysight U1461A is also worth looking at, with its OLED display, although is a tad busy. Cheaper alternatives are the Fluke 1507 and 1503 at around $500, or the Amprobe AMB-45 for $400.
There are cheaper ones out there, but when it comes to leakage and high energies testing especially, avoid going cheap no name brand.
We will link to the above alternatives once reviewed. In the meantime, if you’re not ready for an insulation resistance tester yet, checkout some of our multimeter reviews.