How to Use a Megohmmeter: 3 Listings Compared
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“Megger meter” is a common search term for a megohmmeter, the instrument that applies a DC test voltage and reports insulation resistance. This page explains how to operate one using what three listings say about their controls, test voltages, readings and warnings. It does not replace the manual for any unit, and each step below is taken from a listing’s own text.
The three listings are all handheld megohmmeters. The two Precalixor units also carry full multimeter functions, while the WapoRich is a dedicated megohmmeter with a 2 kΩ continuity range. Listing data was checked on 2026-10-20.
Quick answer
To use one of these meters, first choose the DC test voltage, then start the test, then read the figure and the warnings. The WapoRich lists 250, 500 and 1000 V. The Precalixor PR-T9 lists a wider set, 50, 100, 250, 500 and 1000 V. The Precalixor PR-T7 lists 500 V and 1000 V.
Two of the listings, the two Precalixor units, state a 15-minute auto power-off, and all three state a continuity buzzer in some form. Only the WapoRich describes a lock for continuous testing. The PR-T9 is the only one that names a GUARD terminal for surface leakage.
Comparison table
| Listing | Test voltages stated | Stated insulation ceiling | Start and lock | Power and extra functions |
|---|---|---|---|---|
| WapoRich megaohm meter 1000V, T6-VC60B (first listing) | DC 250, 500 and 1000 V (bullets and highlight) | Up to 200 MΩ (bullets and highlight) | Press and turn the test button downward to lock it (bullets) | Six AA batteries, included; 2 kΩ continuity buzzer below 50 Ω (bullets) |
| Precalixor PR-T7-VC4060-B1, 2-in-1 multimeter (second listing) | 500 V and 1000 V (bullets) | 500 MΩ at 500 V; 2000 MΩ at 1000 V (bullets); 20 GΩ (title) | Press TEST to start; readings auto-hold (bullets) | Battery powered; auto power-off after 15 minutes (bullets); inductance and capacitance functions (bullets) |
| Precalixor PR-T9-SK505A, digital multimeter (third listing) | 50, 100, 250, 500 and 1000 V, selectable (bullets) | Up to 20 GΩ (bullets and title) | Not described in the listing text | Two Li-ion batteries with charging adapter; GUARD terminal; PI and DAR; auto-shutdown after 15 minutes (bullets) |
Step 1: choose the test voltage
Each listing states a set of DC test voltages, and the choice you make sets the ceiling of the reading you can expect. The WapoRich lists DC 250 V, 500 V and 1000 V. The PR-T9 lists 50 V, 100 V, 250 V, 500 V and 1000 V, which gives the widest choice of the three for low-voltage equipment. The PR-T7 lists 500 V and 1000 V in its bullets, with no lower test voltage named.
The listing figures show what each voltage can read. The WapoRich bullets say insulation up to 200 MΩ is measured under its test voltages. The PR-T7 bullets say 500 MΩ at 500 V and 2000 MΩ at 1000 V. Those are the figures to compare when choosing a voltage for the job.
Step 2: start the test and lock it if needed
On the WapoRich, the listing says to press and turn the test button downward to lock it, which lets the unit run a continuous insulation test without holding the button. The bullets describe this as useful for long-duration checks on motors and cables. The PR-T7 listing says to press TEST to start, and that readings auto-hold on the screen once the test ends. The PR-T9 listing does not describe a start or lock action in its text.
The listings do not say whether the meter checks for live voltage before a test starts. Confirm that on the product page, and follow your site’s rules for de-energizing equipment before you connect any lead.
Step 3: read the warnings during a test
During an insulation test, the WapoRich lights a red LED, shows a high-voltage symbol and sounds a rhythmic buzzer, according to its bullets. The bullets say the buzzer changes to a continuous alarm when the insulation reading drops below 5% of the current range or when a short circuit occurs. The PR-T7 lists a high-voltage indicator and an audible alarm during insulation testing.
These are the warnings the listings describe. None of them states how fast the alarm responds, so do not treat them as a substitute for checking the display.
Step 4: read the figure and the over-range display
The WapoRich bullets say the display shows “1″ when resistance exceeds 2 kΩ or the circuit is open, in its resistance mode. The listing calls this a normal over-range indication, and not a malfunction. Data hold is available for voltage and resistance readings but not in insulation mode. The PR-T7 readings auto-hold after a test, and the PR-T9 gives PI and DAR values from timed readings.
The PR-T9 bullets give its PI as the 10-minute reading divided by the 1-minute reading, and its DAR as the 60-second reading divided by the 30-second reading. Those are the ratios the listing names, and the bullets say they are calculated automatically.
Step 5: use the guard terminal and extra functions
The PR-T9 bullets describe a GUARD (G) terminal that suppresses surface leakage on cables and transformers. The listing says this helps readings reflect the insulation itself. The PR-T7 lists a frequency function, a temperature range and a capacitance measurement among its extras, while the WapoRich lists a 2 kΩ continuity buzzer below 50 Ω.
Use the extra functions for the purposes each listing names, and do not read them as a replacement for an insulation test. The listings describe them as extras to the main insulation measurement.
How these three were chosen
Each listing above names a megohmmeter, and the title or highlight describes insulation resistance measurement. Other products in related results, including general multimeters, outlet testers and battery checkers, are left out because they do not measure insulation resistance. Figures come from each listing’s own fields and bullets, and all three were checked on 2026-10-20.
Worked example: the reading that matches a test voltage
Take a 1000 V test as an illustration. The WapoRich states up to 200 MΩ across its test voltages and gives no separate figure for 1000 V. The PR-T7 states 2000 MΩ at 1000 V, which is 2 GΩ, ten times the WapoRich maximum. The PR-T9 states up to 20 GΩ, which is 20,000 MΩ, a hundred times the WapoRich figure. The three listings state the top reading at different conditions, so the figures should not be compared without their test voltages.
The PR-T7 listing has a conflict to check. Its title says 20 GΩ, while its bullet says 2000 MΩ at 1000 V, which is 2 GΩ. Those are different ceilings for the same unit, and the listing does not explain the gap.
What the listings do not say
- None of the three ties an accuracy figure to its lowest test voltage.
- The PR-T7 specification field lists its included components as a user manual, while its bullets describe test leads, clips and a temperature probe.
- The PR-T9 does not describe a start or lock action in its text.
- The listings do not say whether the meters check for live voltage before a test begins.
- None of the three states how long a full reading takes at its top voltage.
The three listings
WapoRich megaohm meter 1000V, model T6-VC60B: DC 250 V, 500 V and 1000 V test voltages, insulation up to 200 MΩ, and six AA batteries listed as included. View this listing on Amazon
Precalixor PR-T7-VC4060-B1, 2-in-1 multimeter: 500 V and 1000 V insulation tests, inductance and capacitance functions, and a 6000-count display. View this listing on Amazon
Precalixor PR-T9-SK505A digital multimeter: selectable 50 V to 1000 V test voltages, PI and DAR calculation, and a GUARD terminal. View this listing on Amazon
Related buying guides
For the general category, the megohmmeter guide covers the main meter types, the megger tester guide covers the models sold under the megger name, and the megohmmeter tester guide covers the handheld models in this group.
FAQ
Which listing offers the widest choice of test voltages?
The Precalixor PR-T9 lists 50, 100, 250, 500 and 1000 V as selectable test voltages. The WapoRich lists 250, 500 and 1000 V, and the PR-T7 lists 500 V and 1000 V.
How do I keep the test running without holding the button?
The WapoRich listing says to press and turn the test button downward to lock it for continuous testing. The other two listings do not describe a lock action.
What does a reading of 1 on the display mean?
According to the WapoRich bullets, the display shows 1 when resistance exceeds its range or the circuit is open. The listing says this is a normal over-range indication and not a malfunction.
Why does the PR-T7 listing give two insulation ceilings?
Its title says 20 GΩ, and its bullet says 2000 MΩ at 1000 V, which is 2 GΩ. The listing does not explain which figure applies at which voltage.
What should I confirm before buying?
Confirm the test voltages you need, whether the unit checks for live voltage before a test, the battery arrangement and the included parts. Check the product page for each, because the PR-T7 listing gives different included items in different fields.
Bottom line
For the widest stated set of test voltages, the PR-T9 is the one to check, and it is also the only listing here with a GUARD terminal. The WapoRich is the one with a stated lock action for continuous testing. The PR-T7 gives inductance, capacitance and temperature functions alongside a 1000 V insulation test, with a ceiling conflict in its own listing. Pick by the test voltage your equipment needs, then confirm the warnings and the lock action on the product page.
