5 Best Insulation Testers for Electricians


Insulation testers are used by electricians to determine whether insulation is safe and effective. These testers typically measure capacitive current, absorption current, and leakage current. They are used to test newly installed equipment or machinery. When testing, the very first test is used to provide a proof test and the second test provides a baseline reading. The baseline reading is then used for future reference.

Let’s take a look at 5 of the best Fluke insulation testers on the market right now:

Fluke 1587FC Insulation Multimeter with Fluke Connect

Fluke 1587FC Insulation Multimeter with Fluke Connect

The Fluke 1587FC Insulation Multimeter with Fluke Connect can test insulation in addition to acting as a digital multimeter.

Complete with testing leads, a hardcover, a 1400 current clamp and an insulation remote probe, the Fluke 1587FC is a very rugged piece of equipment.

This multimeter comes with the ability to measure AC/DC voltage, milliamps and millivolts. There’s also an extended resistance range that comes as standard, along with an auto-discharge of capacitive voltage and a 3-year warranty.

With an easy-to-read display and the ability to stand on its own, the Fluke 1587FC is a good piece of equipment and has proven to be very reliable.

Fluke 1507 Insulation Resistance Tester

FLUKE 1507 Insulation Resistance Tester I

The Fluke 1507 Insulation Resistance Tester allows the user to test in a range of environments due to its multiple test voltages.

Complete with 200mA continuity, 4 alkaline batteries, and a 1-year warranty, the Fluke 1507 is a good tester. With the ability to automatically calculate the polarization index along with the dielectric absorption ration, this insulation resistance tester means business.

The backlit display is large which makes for easy reading and its live circuit detection works to prevent the insulation test if the voltage is greater than 30 volts. With auto-discharge for added protection and a CAT IV 600 volt over-voltage category rating, you have even more user protection.

If you are in the market for an insulation resistance tester that offers a lot, the Fluke 1507 is ideal for you.

Fluke 1503 Insulation Resistance Meter

FLUKE 1503 Insulation Resistance Tester

The Fluke 1503 Insulation Resistance Meter is considered to be a very convenient tester that’s easy to use and lets you measure many different types of insulation.

The backlit display is very easy to read and the insulation test range is 1503: 0.1 MΩ to 2,000 MΩ.

Insulation test voltages are 1503: 500 volts, 1,000 volts. In addition to this, the live circuit detection will prevent a test if more than 30 volts are detected.

Complete with a 1 year warranty and 4 alkaline batteries, the Fluke 1503 has an auto-discharge for added protection and the meter comes complete with alligator clips, probes, a remote probe and test leads.

Fluke 1555 10kV Insulation Tester Kit

The Fluke 1555 10kV Insulation Tester Kit has the ability to test insulation of up to 10 kV and is ideal for testing equipment in plants or factories.

This kit comes with a 3-year warranty, long battery life and a warning function. This function alerts you when a voltage is present.

With resistance measurements up to 2 TΩ and a guard system that eliminates the effect of a surface leakage current, the Fluke 1555 is a good piece of equipment.

Complete with the automatic calculation of dielectric absorption along with a polarization index, this kit also comes with timer settings and a ramp function. If you are looking for an insulation tester kit that seems to do it all, this is the kit you need.

Fluke 1550C 5kV Insulation Tester Kit

Fluke 1550C 5kV Insulation Tester

The Fluke 1550C 5kV Insulation Tester Kit has been designed for use in industrial environments and is, therefore, a very rugged kit.

Ideal for testing insulation within transformers, motors, switch-gears, and panels, along with large-scale installations, the Fluke 1550C could be exactly what you need.

Complete with a 3-year warranty and the ability to test voltages up to 5 kV, users may also benefit from the selectable test voltages.

The selectable voltages are available in 50-volt steps, from 250 volts up to 1,000 volts. There are also selectable voltages from 100-volt steps above 1,000 volts. If you are in need of an insulation tester kit that is designed for use in industrial environments, this could be the ideal kit for you.

What to Consider when Buying an Insulation Tester

There are many different insulation testers for electricians on the market right now. However, we consider the 5 testers listed above to be the best among them. Take a look at each and determine which one meets all of your needs.

If you are considering a tester, you need to firstly look at the voltage requirements. The output voltage needs to be based on the DC insulation resistance test voltage. You will also need to consider measuring current. Are you planning to measure polarization current or leakage current? Knowing which type of current you need to measure can help you decide which insulation tester to purchase.

You will also need to take into consideration how much experience you have with insulation testers. If you have a lot of experience and can interpret readings very well, you can potentially use any tester out there. If you don’t have a lot of experience, you should look for a tester that is simple and has a limited range of functions. Ideally, you should have some insulation resistance testing training, so you know what you’re looking for.

This post is part of a series for electricians:

Lastly, you will need to take the environment into consideration. Are you planning to use the insulation tester outdoors or inside? Where are you likely to use the tester, will you be using it in a factory of a shop? There is also another consideration that you need to think about, that relates to whether you will be using the tester for preventative maintenance, troubleshooting or both. All of these different factors can determine the type and size of tester that you need.