When it comes to electrical insulation testing, a megohmmeter and a high-potential tester (or hi-pot for short) are two of the most common tools for this purpose. Both tools serve the same function but produce very different results.

Megohmmeters and hi-pot testers are used to measure the leakage current through insulation by applying a high voltage across it. A megohmmeter measures something, while a hi-pot tester does something about it. Just what does that entail? Let’s dig into the differences between megohmmeters and hi-pot testers and when you’d want to use each.

What Is a Hi-Pot Tester?

A hi-pot tester, as one might guess from the name, employs greater levels of voltage and current than a megohmmeter. The primary purpose of this tool is not measurement but rather elimination of the weak, such as removing a marginal device from service by destroying its weak insulation to prevent a costly malfunction.

(Hi-Pot AC or DC voltage can be used for pot testing. Because DC models are larger than AC models, they are typically too large to be field tested.)

What Is a Megohmmeter?

A megohmmeter is used to measure the electrical resistance of insulators. It subjects a DUT to a direct current voltage ranging from 300 to 15,000 volts and measures the low currents that flow because of insulation breakdown. Currents as small as a few nanoamps or microamps can be detected by the megohmmeter. Because the small currents produced by megohmmeters do not harm insulation, they can be used for routine testing and maintenance.

Megohmmeter vs. Hi-Pot: Which One Should You Choose?

Simply put, a megohmmeter measures the insulation resistance, while a hi-pot tester helps you find the leakage current in your equipment’s insulation.

You should think about the DUT you’ll be testing, the testing current you’ll need, and your personal preference when deciding whether to buy a megohmmeter or a hi-pot tester. Budget, size constraints, and the DUT’s current lifecycle stage are also important considerations.

The megohmmeter, with its small currents and ability to perform routine maintenance checks, may be the better choice for those interested in tracking the longevity of their equipment. If, however, you want to conduct dielectric withstand tests and ensure product safety during development and production, a hi-pot tester is the way to go.

Find the Right Testing Instrument at TestEquity

Whether you are searching for a hi-pot or a megohmmeter, TestEquity provides a vast selection of high-quality instruments that make testing electrical insulation a breeze. The portability of these instruments is enhanced by their small size, and the large display makes viewing measurement results convenient. Not certain which model to select? Our sales staff is prepared to assist you in selecting the appropriate instrument for your application. Contact us today at 1-800-950-3478 or via our website.