When working with electrical wiring that runs gigantic pieces of machinery, a major malfunction at any point can cost a company thousands of dollars in lost time. As well as the time is money cost of a piece of downed equipment, there comes the manpower required to fix it, as well as the loss in production hours as the problem is resolved.
One of the ways to avoid losses of this sort is to frequently test the insulation resistance of electrical wiring – there are two basic ways to perform this test. The first is using an insulation resistance tester or an IR tester. The second method is to use a megohmmeter, informally known as a “Megger”.
Some people incorrectly use these two types of testers synonymously, however there are a few key differences between an IR tester and a megohmmeter.
What is an IR Tester?
An insulation resistance tester is a device that is used to measure the amount of electrical resistance provided by any two points on a circuit that are under insulation resistance. You can test an IR tester’s functionality by placing one lead on the wire that you’re testing and one lead on the ground or other metal object. You should receive a reading of more than ten Megaohms (MOhms) if the motor that you’re testing is in good working order.
IR testers do not only perform megaohm tests. They also perform more complex testing at higher voltage levels. Most basic IR testers perform tests at 1000 volts – so do Megohmmeters – however, some IR testers are able to perform tests at 5000 volts and some even include the ability to compensate for various environmental factors, which can affect the insulation resistance of wiring.
Some IR testers will also save information to a cloud-based service and save measurement history to make it easier for workers to check their measurements from last time, if they’re on a repeat call.
What is a Megohmmeter?
Megohmmeters operate by sending a very high voltage into the object being tested, the readings are often very high resistance values, measured in Megaohms. However, Megohmmeters usually only perform this singular function.
Megohmmeters also do not typically perform tests past 1000V, which significantly limits their utility to an electrician. Megohmmeters also don’t typically have cloud-based storage functionality, or any compensatory technology at all.
What is the Difference Between a Megohmmeter & An IR Tester?
The most basic difference between an IR tester and a megohmmeter is their functionality and technological integration. While most megohmmeters are single-function, some older models are even hand-cranked, whereas IR testers tend to be completely electronic, offering much more accurate readings.
An IR tester will also perform both a continuity test (seeing if there is continuous current flowing through wiring), and a diode test – diodes are electrical connectivity points where currents flow – where as a basic megohmmeter may not even perform diode testing. Diode testing is a critical part of electrical testing.
IR testers and Megohmmeters perform similar functions at the most basic levels, but an IR tester far outperforms the megohmmeter in terms of complex functions and complex testing, which is why IR testers are often favoured to megohmmeters.