Supco M500 Insulation Tester/Electronic Megohmmeter - Handheld 0-1000M

In this review the Supco M500 Insulation Tester is evaluated as a practical, budget-friendly tool for technicians who need a fast way to check insulation resistance. The bottom line: it is best for maintenance techs, HVAC and motor repair professionals who want reliable insulation readings up to 1000 me ohms without the cost or bulk of precision laboratory gear. The M500 delivers clear measurements at 500 VAC, stores test leads in its soft carrying case and is compact enough for field use, making it a solid diagnostic companion when speed and portability matter.

Key Features

• Insulation range: Measures insulation resistance from 0 to 1000 me ohms, allowing users to spot deteriorating or heat-damaged insulation on motors and compressors.
• 500 VAC test voltage: Uses a 500 VAC test level that is appropriate for verifying motor winding insulation and many refrigeration and appliance circuits.
• Zone scale: The zone scale gives a quick visual indicator of insulation condition, which speeds troubleshooting and reduces guesswork on the job.
• Portable design: The handheld unit is impact resistant and comes with a soft carrying case that stores test leads, making it easy to transport and protect on site.
• Battery powered: Operates on two C batteries so it can be used away from mains power for field diagnostics and maintenance checks.

Who It's For

The Supco M500 is aimed at service technicians, refrigeration and HVAC professionals, and maintenance crews who need a straightforward instrument to diagnose motor windings, hermetic compressor insulation, and control circuit deterioration. Its portability and zone scale are especially useful during routine preventative maintenance and quick fault isolation.

Those who need laboratory-grade, high-precision insulation measurements or extended warranty support might look elsewhere; also buyers who require very long test lead reach should consider models with longer or detachable leads.

Pros & Cons

Pros

• Simple, fast insulation checks up to 1000 me ohms that save time on diagnostics.
• Compact, impact-resistant handheld design with a soft carrying case for protected transport.
• Clear zone scale and accurate readings make it easy to interpret insulation condition without extensive training.
• Operates on common C batteries so it runs in the field without external power.

Cons

• Some users report the included test leads are shorter than ideal for certain tasks, limiting reach on larger equipment.
• A few buyers noted durability issues in isolated cases, so expect mixed ruggedness compared with higher-priced swing-needle instruments.

Specifications

Measurement / Function	Insulation resistance
Range	0 to 1000 me ohms
Test Voltage	500 VAC
Power	2 C batteries (not included)
Form Factor	Hand held, impact resistant
Case	Soft carrying case with test lead storage
Typical Applications	Motor windings, hermetic compressors, appliances, panel boards, relay control circuits

Our Verdict

The Supco M500 is a practical, cost-effective insulation tester for technicians who need quick, accurate checks in the field. It offers meaningful readings up to 1000 me ohms, a useful zone scale and convenient portability, making it good value for routine maintenance and troubleshooting. Those needing lab-grade precision or longer leads may prefer a higher-end instrument, but for most service tasks the M500 delivers solid performance at a modest price.

Frequently Asked Questions

What voltage does the tester use?
The unit performs insulation tests at 500 VAC.

Are batteries included?
No, the M500 operates on two C batteries which are not included.

Can it test motor winding insulation?
Yes, the M500 is suitable for diagnosing motor winding insulation and heat-damaged insulation in compressors and appliances.