If you're shopping for electrical testers and multimeters that handle insulation resistance, the decision usually comes down to how much certainty you need versus how much you want to spend. The Fluke 1507 Insulation Resistance Tester is listed at USD 611.00, while the Megger MJ459 Insulation Resistance Tester is listed at USD 59.99. That's a wide gap, and the two testers approach the same job from different directions.
Quick verdict
If your work demands a wide range of insulation test voltages, automatic ratio calculations, and calibration documentation, the Fluke 1507 is the clear pick. If you need a less expensive megohmmeter for occasional checks and can accept a used instrument, the Megger MJ459 is the cheaper choice.
| Attribute | Fluke 1507 | Megger MJ459 |
| Price | USD 611.00 | USD 59.99 |
| Condition | New (open box) | Used, good working |
| Brand | Fluke | Megger |
Where each wins
The Fluke 1507 wins on capability and traceability. It provides five insulation test voltages, a resistance range from 0.01 MΩ to 10 GΩ, automatic Polarization Index and Dielectric Absorption Ratio calculations, a pass/fail compare function, live circuit detection, and auto-discharge of capacitive voltage. It also comes with NIST-traceable calibration data.
The Megger MJ459 wins on price. At the low end of this comparison, it makes insulation testing accessible without the higher upfront investment. It is a used unit listed in good working condition, which explains the price gap.
Product notes
Fluke 1507 Insulation Resistance Tester 1000v NEW IN Open Box
The Fluke 1507 is a full-featured insulation tester aimed at electrical contractors and industrial electricians. It supports 50, 100, 250, 500, and 1000 V insulation test voltages, and its insulation resistance range covers 0.01 MΩ to 10 GΩ. The automatic Polarization Index and Dielectric Absorption Ratio calculations make it easier to assess insulation condition over time. The compare function is useful for repetitive pass/fail checks, while live circuit detection and auto-discharge of capacitive voltage add protection. The main limitation is cost: this tester sits at the high end of the price comparison, so it is a significant investment for tools that may only see occasional use.
Megger MJ459 Insulation Resistance Tester
The Megger MJ459 is a used insulation resistance tester listed in good working condition. Its main strength is the low price, which puts a megohmmeter within reach for buyers who want to spend less. It is a straightforward option when you need a basic insulation tester and can work with the limitations of a used instrument. Because the unit is used, you do not get the same assurance as a brand-new tester with calibration documentation. If the tester performs as described, the price advantage is substantial, but the used condition means you should be comfortable with some uncertainty in long-term accuracy.
Final choice by use case
Choose the Fluke 1507 when you need a dependable insulation tester with multiple test voltages, automatic calculations, and calibration documentation. It suits professional contractors and maintenance teams that rely on accurate, repeatable insulation testing.
Choose the Megger MJ459 when you want to spend less and the basic ability to test insulation resistance is more important than the advanced extras. It works best for occasional users who can accept a used tester and the unknowns that come with it.
