Best Analog Insulation Tester: 4 Megohmmeters Compared

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An analog insulation tester is a megohmmeter with a pointer or analog-style scale, used to read insulation resistance. This guide compares four boards from their listings. Two listings name an analog display clearly, and two list both digital and analog features in the title. Insulation testers apply high test voltages, so read the manual’s safety section before you connect any leads. Work on energized equipment or panels belongs to a licensed electrician. Compare test voltage, display type and power source before you compare anything else. One listing in the group describes LED indicators only, and it is left out of the comparison.

Quick answer

Pick GuliTech if you want a plain analog megohmmeter on a single 500V range, with auto discharge and a push switch for one-shot or continuous readings. Pick Triplett if you want an analog display with three test voltages, 250V, 500V and 1000V, and a lock feature for hands-free readings, but do not rely on its insulation range until the listing is consistent. Pick KYOHRITSU or evhooe if you need a digital and analog display, and check the display type on the listing because each one also says digital in its style field.

What matters for this keyword

An analog insulation tester answers a narrow question: how much resistance the insulation offers at a chosen test voltage. These points change with the keyword, so check each one against your job.

• Display type. Analog means a pointer or scale. Two listings describe analog displays in their titles, and two list both digital and analog. The Wikipedia entry on multimeters notes that digital meters have numeric displays and are more precise than analog meters with a moving pointer.
• Test voltage. Each listing gives different test voltages. GuliTech lists a single 500V range, Triplett lists 250V, 500V and 1000V, evhooe lists 50V to 1000V, and KYOHRITSU lists 250, 500 and 1000V.
• Insulation range. The listings state ranges in megohms, but two of them disagree with their own titles or bullets. Read the range on the listing before you compare numbers.
• Power source. GuliTech and KYOHRITSU list battery power. evhooe lists corded electric, which the bullets do not explain.
• Extra functions. Some boards add AC voltage, continuity or live circuit warnings. These help with other checks, but they do not change the insulation reading.

How to choose

Choose by the test voltage you need and the display you can read best.

• Choose GuliTech if you want an analog readout on one 500V range and you can accept a single test voltage. Its bullets list an auto discharge function, which is useful after a test.
• Choose Triplett if you want an analog display with three test voltages and a lock-on feature for longer readings. Clear up the insulation range with the seller or the manual before you rely on it.
• Choose evhooe if you want a wide test range from 50V to 1000V and automatic polarization index and dielectric absorption readings, and you can work with a corded supply.
• Choose KYOHRITSU if you want a bar graph for insulation resistance, a live circuit warning buzzer and three test voltages. Check the display type first.

Before you buy, check the test voltages, the display type and the power source on the listing. If the listing gives two different figures for the same range, do not guess which one is right.

Reading an analog scale

A pointer reads a value against a scale, and the Wikipedia entry on multimeters describes analog meters as less precise than digital ones with numeric displays. That difference matters when you record a result. Write down the test voltage with each reading, along with the scale value and the time of the test. A pointer that sits between two marks is still a reading, but you should record it as a range rather than a single number. Backlit scales help in a dim panel. The Triplett and evhooe listings both state a backlight, so on paper they suit dim spaces better than the other two.

Choosing a test voltage

The listings give four different test-voltage sets, and the right one depends on the equipment the manual names. GuliTech stays on one 500V range, Triplett and KYOHRITSU offer 250V, 500V and 1000V, and evhooe covers 50V to 1000V. Match the test voltage to the rating in the equipment manual, not to the tester that has the widest range. A wide range is useful only when you know which voltage the job needs. For a wider look at insulation tools, see the insulation resistance tester guide, the digital insulation tester guide and the electronic insulation tester guide.

Reading the extra functions

Most of these testers do more than insulation. Triplett lists AC voltage and low resistance measurement, along with a live circuit LED indicator. evhooe lists AC and DC voltage and continuity testing, and its bullets name automatic polarization index and dielectric absorption calculations. KYOHRITSU lists continuity ranges of 20, 200 and 2000 ohms with 200mA measuring current on continuity, plus a live circuit warning buzzer. GuliTech lists a DC voltage range of DC60V in its bullets and nothing else beyond insulation. Use the extra functions only where the listing states them, and do not assume a function the listing does not mention.

Where the listings disagree

Three of the four listings have a field that conflicts with another field or with the title. Triplett’s title gives 400GΩ while its bullets give 400MΩ. GuliTech’s title names two models, DM509S and DM1009S, while its specs name only DM509S. evhooe and KYOHRITSU name analog in their titles, but both list digital in their style fields. KYOHRITSU also spells its brand and manufacturer names differently. When a conflict affects a number you need, confirm the figure with the seller or the manual before you rely on it.

Motors and cables in practice

Motors and cables are the two kinds of equipment the listings name most often, and they call for different records. For a motor, record the winding or terminal you tested with the reading, so the value can be compared later. For a cable, record the run or the connection, since the reading depends on the path. The evhooe bullets name both motors and cables as examples. Use the same log layout for every job, so the readings line up when you compare them. A simple sheet with a column for the voltage, the value and the time is enough for most rounds, and it makes a repeat test easy to match against the first one.

The listing left out

One listing in the group describes an insulation tester with LED indicators and a digital display, and it does not name an analog display anywhere in its title or specs. It is left out of this comparison so the analog choice stays clear.

Safety for insulation testing

Insulation testers apply high test voltages. The listings name 250V, 500V and 1000V test levels, so the manual’s safety section comes before the first connection. Read it before you connect any lead, and test only equipment the manual covers. The OSHA rule for listed or labeled equipment is to install and use it according to the instructions in its listing or labeling. Follow those instructions, and keep work on energized equipment or panels with a licensed electrician. Before each round, look over the test leads for cuts or worn insulation, and replace a damaged lead before you test, because a damaged lead can change a reading and creates its own hazard.

Worked example: a motor check round

If each reading is recorded with its voltage and time, the log holds 18 lines. A round like this suits a meter with a single test voltage, because you do not switch ranges between motors.

Now take the same motors in two rounds of three. If the first round finds a motor that needs follow-up, you can finish that motor in the second round without repeating the whole batch. Keep the log for each round separate, so a later comparison uses the same test voltage for each reading.

Mistakes that make a reading hard to use

• Trusting the word analog in a title. evhooe and KYOHRITSU both name analog in the title, but their style fields say Digital. Check the display on the listing before you assume one.
• Quoting a range you have not checked. Triplett’s title gives a 400GΩ resistance figure, while its bullets give 400MΩ. The article quotes neither, and you should confirm the figure before you use it.
• Ignoring the test voltage. Each reading depends on the voltage it was taken at. Record the voltage with every reading, or the value means little later.
• Using the typical range as a pass mark. The Wikipedia entry on megohmmeters says acceptable insulator resistance is typically 1 to 10 megohms, depending on the standards referenced. Use the standard for your equipment, not the typical range.
• Overlooking the power source. evhooe lists corded electric, while GuliTech and KYOHRITSU list battery power. Plan the job around that supply, not around the display alone.

FAQ

What is an analog insulation tester used for?

It measures the resistance of insulators. The Wikipedia entry on megohmmeters explains that insulating components are tested for insulation strength at commissioning and during maintenance of high-voltage equipment. A megohmmeter provides high DC voltages, typically from 500 V to 5 kV, and some reach 15 kV.

Are analog insulation testers more accurate than digital ones?

Not in general. The Wikipedia entry on multimeters says digital meters are more precise than analog meters with a moving pointer. An analog display can still be useful for watching a reading change over time, which is why some listings keep one.

What test voltage should I choose?

Choose the voltage the equipment manual or your standard calls for. The listings give different options: GuliTech offers one 500V range, Triplett offers 250V, 500V and 1000V, and KYOHRITSU lists 250, 500 and 1000V. evhooe covers 50V to 1000V.

Which board suits motors and cables?

evhooe’s bullets name motors and cables as examples of equipment to check, and they add automatic polarization index and dielectric absorption readings. The bullets do not say how those readings are used, so follow the manual or your standard for the calculation.

Can these testers check continuity too?

Some of them. Triplett lists AC voltage and low resistance measurement. KYOHRITSU lists a continuity range and a live circuit warning buzzer. evhooe lists continuity testing in its bullets. Check each function on its listing before you rely on it.

Does the title or the style field tell me the display type?

Neither alone. The title and the style field disagree on evhooe and KYOHRITSU, and the bullets are the tie-breaker. Confirm the display on the listing or with the seller before you order.

What does the lock feature on Triplett do?

The Triplett bullets describe a Lock Power feature for hands-free operation. The listing does not say how long the lock holds or how it releases, so read the manual before you rely on it for a long reading.

Who should handle energized equipment?

A licensed electrician should handle work on energized equipment or panels. This guide covers the choice of tester, and the safety section of the manual covers the use of the tester.

Bottom line

Choose the tester by the test voltage and the display you need. Pick GuliTech for one 500V analog range. Pick Triplett for an analog display with three test voltages once its range is confirmed. Pick evhooe for a wide 50V to 1000V range and corded power, and KYOHRITSU for a bar graph with three test voltages after you confirm the display type. Record the test voltage with every reading, and follow the manual’s safety section.

Sources

• Megohmmeter: insulating components are tested for insulation strength, and megohmmeters provide high DC voltages from 500 V to 5 kV
• Multimeter: digital meters have numeric displays and are more precise than analog meters with a moving pointer
• OSHA 29 CFR 1910.303: listed or labeled equipment is installed and used according to the instructions in its listing or labeling