Insulation testing is one of those jobs where a reliable meter makes all the difference, so I spent some time putting the Fluke 1507 Digital Megohmmeter through its paces on motors, cable runs, and a few panels that had seen better days.
It gives you five test voltages, from 50V up to 1000V, which covers most of what I run into on industrial and electrical work.
What I appreciated most was how little thinking it asked of me. The 1507 works out the polarization index and dielectric absorption ratio on its own, and the pass/fail compare mode meant I could run the same test over and over without checking numbers each time.
The remote probe earned its keep on a few awkward overhead connections, and the backlit screen stayed readable in a dim mechanical room. Live circuit detection blocks the test if it senses more than 30 volts, which is a sensible safeguard.
It isn’t perfect. At 3.2 pounds with the holster it’s heavier than a basic meter, and it runs on four AA batteries rather than a rechargeable pack, so I’d keep spares in the bag. There’s also no magnetic hanger included, which is a separate purchase.
Bottom Line
The Fluke 1507 does what a good insulation tester should do: it gives you clear readings, handles the math for you, and protects you from live circuits.
If you do regular maintenance or troubleshooting work and want a meter that will hold up in the field, check the current price on the Fluke 1507 here.
Overview: Fluke 1507 Digital Megohmmeter Resistance Tester
Insulation testing used to mean hauling around a bulky crank-style tester and doing math on paper. That is not the case with this handheld unit.
The 1507 offers five test voltages — 50V, 100V, 250V, 500V, and 1000V — so I could check anything from control wiring to motor windings with one tool. It also calculates the Polarization Index and Dielectric Absorption Ratio on its own, which saved me time on longer tests.
A few things I appreciated during use:
- Live circuit detection blocks the test if it senses more than 30V, and it auto-discharges stored voltage afterward.
- The remote probe made testing in tight spots much easier without a second person.
- The compare (pass/fail) mode is handy for repeat checks on multiple circuits.
- The backlit display stays readable in dark panels.
My main gripes: the TPAK magnetic hanger is sold separately, and it runs on four AA batteries rather than a rechargeable pack.
Multiple Insulation Test Voltages
Having five test voltages on one dial makes a real difference in the field. The 1507 gives you 50V, 100V, 250V, 500V, and 1000V, and I found myself switching between them more often than I expected.
Here’s how I used each one:
| Voltage | What I tested |
|---|---|
| 50V / 100V | Low-voltage control wiring and sensitive electronics |
| 250V | Smaller motor windings and appliance circuits |
| 500V | Standard building wiring and branch circuits |
| 1000V | Larger motors, feeders, and industrial equipment |
The selector dial is easy to turn with gloves on, and there’s no menu digging to find the setting you want.
One small limitation: 1000V is the ceiling here. If you regularly test medium-voltage cable that needs 2500V or 5000V, this model won’t cover it.
For most electricians and maintenance techs, though, the range fits daily work well.
Automatic Polarization Index And Dielectric Absorption Calculations
Testing motor windings used to mean holding a stopwatch and doing math on a notepad. The 1507 handles that part for me.
I ran a timed insulation test on a three-phase motor, and the meter tracked the readings and gave me the polarization index (PI) and dielectric absorption ratio (DAR) on its own. No dividing one reading by another after the fact.
Here’s why that matters:
- PI compares the 10-minute reading to the 1-minute reading
- DAR compares the 60-second reading to the 30-second reading
- Both help show if insulation is drying out or holding moisture
The backlit screen made the numbers easy to read in a dim electrical room.
One thing to know: the 10-minute PI test still takes 10 minutes, so plan for the wait. The meter just does the counting and the math for you.
Remote Probe And Pass/Fail Testing Workflow
Testing motor windings inside a crowded panel used to mean climbing up and down a ladder for me. The included remote probe changed that. I could set the meter down, hold the probe at the test point, and start the test right from my hand.
The compare function is the other part that saved me time. I set a minimum resistance value, ran the test, and the 1507 simply told me whether the reading passed or failed.
Where this helps most:
- Repeated tests on many identical circuits or motors
- Hard-to-reach points where you can’t watch the display
- Quick screening when you only need a yes or no answer
One note: the remote probe cable isn’t very long, so I still had to place the meter fairly close by. And you’ll want to double-check your pass/fail threshold before you start, since a wrong setting gives you confident but useless results.
Live Circuit Detection, Auto-Discharge, And Backlit Display
Safety features can feel like an afterthought on some testers. Not here.
The first time I clipped onto a panel that still had voltage on it, the meter refused to run the insulation test. Anything above 30 volts and it simply blocks the test. That saved me from a mistake I’ve seen other people make.
After a test on a long cable run, the 1507 discharges the stored capacitive voltage on its own. I still wait a moment before touching anything, but it’s one less thing to worry about.
A few things I noticed while using it:
- Backlit screen is large and readable in a dark crawlspace or unlit switchgear room
- Numbers stay clear when you’re holding the meter at an angle
- The backlight does drain the four AA batteries faster, so I turn it off outdoors
Simple protections, but they matter daily.
Included Accessories And Calibration Readiness
Opening the box, I found everything I needed to start testing that same afternoon. No extra shopping trip required.
Here’s what came packed inside:
- TL224 silicone test leads
- TP74 test probes
- Alligator clips
- Remote test probe for one-handed testing in tight spots
- Protective holster
- Four AA batteries
The remote probe turned out to be the piece I used most. It made repeated tests on a panel far easier than juggling two separate leads.
My unit also arrived with a NIST-traceable calibration certificate that included the actual data. That saved me from sending it out before putting it into service, which matters if your workplace follows a quality standard.
One small gap: the tpak magnetic hanger isn’t included. If you want to hang the 1507 while you work, that’s a separate purchase.
Fluke covers it with a one-year warranty.
Best-Fit Users And Applications
Not every insulation tester belongs in every toolbag. After spending time with the 1507 on motors, panels, and a few long cable runs, I have a clear sense of who gets the most out of it.
Industrial Maintenance Technicians
If you check motor windings, transformers, or drive cables on a schedule, this meter fits that routine well. The five test voltages (50V through 1000V) cover most plant equipment, and the automatic Polarization Index and Dielectric Absorption Ratio calculations save me from doing timed tests with a stopwatch and a notepad.
The compare function is the feature I reached for most. I set a pass/fail limit once, then ran through a row of motors without re-reading the display value every time.
A few practical notes from my testing:
| What I liked | What to keep in mind |
|---|---|
| Backlit display is readable in dark motor rooms | No hard case included at this price |
| Remote probe helps with awkward terminal boxes | Battery drain is real on long PI tests |
| Auto-discharge after each test | You still need to know safe test voltages |
One reviewer put it plainly: you should understand what you are testing before applying 1000V to it. I agree. This tool will not stop you from choosing a voltage that damages sensitive equipment.
Electrical Contractors And Commissioning Teams
For contractors doing acceptance testing on new installs, the 1507 handles the basics without extra features you may never touch. It performs earth bond resistance measurements too, which covers a common commissioning step.
The CAT IV 600V rating and live circuit detection matter here. When I accidentally clipped onto a circuit that still had voltage on it, the meter blocked the insulation test instead of proceeding.
Who might want something else:
- Field crews needing data logging — the 1507 does not store or download results, so the 1587 or a similar model makes more sense
- Anyone testing above 1000V — this unit stops there
- Occasional users — the price is hard to justify for a few tests a year
For daily or weekly use in industrial and commercial settings, though, it earns its place.
Pros And Cons
After spending time running insulation tests with the 1507, I have a clear sense of where it shines and where it falls short. Here’s my honest breakdown.
Pros
- Five test voltages in one tool. Having 50V, 100V, 250V, 500V, and 1000V available means I can match the test to the equipment instead of guessing.
- The display is easy to read. The backlight helped when I was working in a dim panel room, and the numbers are large enough to read at arm’s length.
- Live circuit detection. If the meter senses more than 30 volts, it blocks the insulation test. That saved me from a mistake more than once.
- The remote probe is genuinely useful. Testing overhead or in cramped spaces is much simpler when I can trigger the test from the probe instead of reaching back to the meter.
- It arrives calibrated. Mine came with a NIST-traceable certificate and data, so I could put it to work the same day.
- Reliability. Several long-time users mentioned running Fluke gear for a decade or more without issues, and the build quality here matches that reputation.
Cons
- No hard case included. For a tool at this price, I expected some real protection. A few reviewers made the same complaint, and I agree — you’ll likely want to buy a case separately.
- There’s a learning curve. This isn’t a point-and-shoot meter. One reviewer admitted he didn’t know what counted as an acceptable insulation reading until he used it. Another warned that applying high test voltage to the wrong equipment can cause damage. You need to understand what you’re testing first.
- Fewer features than the 1587. If you want a built-in multimeter for general electrical work, this isn’t it. The 1507 is an insulation tester, full stop. I kept a separate meter on my belt for everything else.
- It’s a specialty purchase. At roughly 1 pound and built for one job, it’s hard to justify unless you test insulation regularly.
Overall, the tradeoffs feel fair. You’re paying for accuracy and durability, not extras.
Customer Reviews And Real-World Impressions
Across roughly 280 ratings, the 1507 holds a 4.5-star average, and my time with it lines up with what most owners say.
What people like:
- Speeds up troubleshooting, especially checking motor leads to frames and transformer windings
- Clear digital display that’s easy to read in the field
- Built tough enough for on-site work
- Long-term buyers report years of reliable use
Common complaints:
- No hard carrying case included, which some feel is unfair at this price
- Fewer features than the pricier 1587
One point several reviewers raise is worth repeating: this tool applies high test voltages, so you need to know what you’re testing before you connect. I found the menus simple, but the results only mean something if you understand acceptable insulation values.
For me, it did exactly what I bought it for — nothing more, nothing less.
Conclusion
After putting this megohmmeter through a few weeks of motor and transformer checks, I feel comfortable saying it earns its price for people who test insulation regularly.
What I liked:
- Five test voltages cover most jobs, from 50V up to 1000V
- The remote probe saved me trips up and down a ladder
- Automatic PI and DAR math meant less time with a calculator
- Live circuit detection blocked the test when it sensed over 30V, which is reassuring
What bothered me:
- No hard case included, which several other buyers pointed out too
- It assumes you already understand what the readings mean
The 1507 isn’t a beginner’s tool. If you know what acceptable insulation values look like for your equipment, it gives fast, readable answers.
If you only need a megger and not a full multimeter, this one does the job well.