Hipot Test: What is it? (Standards & Test Procedure)

Hipot testers are essential for determining the insulating resistance and current carrying capacity of electronic devices.

The device is put through its paces by passing a current through its insulation (DUT).

Insulation’s leakage current loss rate and, thus, its reliability in protecting users can be measured through hipot testing.

What is A Hipot Test?

Hipot testing, short for “high potential,” involves putting electronic devices through rigorous voltage and current stress to ensure they can handle extreme conditions.

Electrical insulation can be tested with a hipot tester to make sure it can withstand the device’s load and prevent electric shock from occurring during regular operation.

The device is exposed to a high voltage for an extended period of time, simulating the effects of a failure in what is called a dielectric withstand test.

Measurements of low resistance and high-current outputs are two of the most useful tests a hipot tester can perform.

Hipot testing is used by producers of electrical equipment to determine the highest voltage at which their products will continue to function safely.

In addition to its primary application, it is also put to use as a risk assessment tool by factories and labs to guarantee the quality and security of their electrical and electronic products.

Why is HIPOT Testing Important?

To guarantee that electrical equipment poses no risk of harm to its users, it must undergo rigorous safety testing.

Beaker High Voltage

Assuring the electrical device’s safety through testing is an essential aspect of the production process.

When electrical equipment poses a shock risk, it may be banned from sale and never made available to consumers.

Verify that the product you plan to use or sell has been subjected to all applicable safety testing and has been found to be totally safe.

Products that haven’t been thoroughly tested could endanger users or workers.

In order to keep up with the standards set by NRTL, it’s important to do regular inspections and maintenance on all of your sensitive electronic equipment.

To keep your certification current, you must also do routine maintenance on high-potential voltage and current test equipment.

Hipot Test Standard

The NRTL program at OSHA spells out the specifics of hipot testing for each class of electronics that necessitates routine inspection.

Regardless of the specific type of testing being conducted, the following general requirements must always be met:

120,000-Ohm Minimum Tester Tolerance

Dielectric withstand testing requires a hipot tester with a sensitivity set so that, when a 120,000-ohm resistor is attached across the output, the tester does not report failure at any output voltage outside of the allowed testing range.

No Breakdowns

Dut Breakdown

There are standards that don’t specify a maximum value but instead mandate that failure must not occur under any circumstances.

This indicates that the circuit requires a certain amount of resistance between any two sites but that this resistance can vary considerably.

These days, determining a circuit’s limits with a dielectric withstand test gadget is a lot more nimble than it always was.

In this guide on electrical safety testing, you will discover a comprehensive chart outlining the various categories of high-voltage devices and the maximum voltages at which they should be tested.

Hipot Test Procedure

When performing hipot tests, one end of the supply is linked to the safety ground, and the other is attached to the conductor under evaluation.

If you need to isolate the electrical insulation on the test lead and you have more than two leads, ground the others and connect only the last cable.

Wait a brief while after applying a voltage to the test circuit before inspecting the current flow.

If the insulation is good enough, there won’t be much of a difference in voltage between the hot wire and the ground line, and there won’t be much current flowing, therefore, the capacitive power discharge will be negligible.

The current limit of the hipot tester can be exceeded if an excessive voltage is applied to one side of the device test cables and the insulation is damaged or deteriorated.

Since you’ll be dealing with both alternating current (AC) and direct current (DC) circuits, you should know how the hipot techniques are implemented for each.

Ac Dc Hipot

AC Hipot Testing

A ramp time is unnecessary for an AC hipot exam.

The requirement to discharge the test instrument or cable once testing is over is eliminated in AC testing, and both voltage polarities can be checked simultaneously.

While AC hipot testing is more trustworthy than DC testing, it also exposes the operator to greater danger.

AC tests are more often recommended by regulation agencies than DC tests, despite the fact that they put more strain on the DUT due to the higher voltages and currents used.

DC Hipot Testing

Lower-power devices can be used for DC testing, reducing the risk to the operator and the workload on the testing apparatus.

In addition, DC hipot testing could make it simpler to collect precise readings from high-capacitance devices.

DC hipot tests detect leakage currents more accurately than AC testing while putting far less strain on the conductors of the DUT.

When testing DC circuits, however, it’s more complicated because the ramp time varies from device to device, and you have to configure it before you begin testing.

This means that while assessing voltages and currents using a DC tester is less dangerous and more cost-effective than with an AC tester, it is also significantly less accurate.

For this reason, DC testing procedures for device safety certification are accepted by a much smaller number of safety bodies.

Conclusion

It is impossible to test the insulating resistance and current carrying capability of electrical equipment without a hipot tester. To simulate the repercussions of a failure, a dielectric withstand test subjects the device to a high voltage for a lengthy period of time. The sensitivity of the hipot tester must be adjusted for dielectric withstand testing such that a 120,000-ohm resistor connected across the output does not trigger a failure indication. While limits aren’t set in stone, standards generally insist that failure never take place. AC hipot testing is more reliable but puts the operator in harm’s way. With a high enough voltage, the hipot tester won’t overheat, but with too much, it won’t be able to handle the current.

Content Summary

  • Hipot testers are essential for determining the insulating resistance and current carrying capacity of electronic devices.
  • To guarantee that electrical equipment poses no risk of harm to its users, it must undergo rigorous safety testing.
  • To keep your certification current, you must also do routine maintenance on high-potential voltage and current test equipment.
  • Dielectric withstand testing requires a hipot tester with a sensitivity set so that, when a 120,000-ohm resistor is attached across the output, the tester does not report failure at any output voltage outside of the allowed testing range.
  • These days, determining a circuit’s limits with a dielectric withstand test gadget is a lot more nimble than it always was.
  • In this guide on electrical safety testing, you will discover a comprehensive chart outlining the various categories of high-voltage devices and the maximum voltages at which they should be tested.
  • When performing hipot tests, one end of the supply is linked to the safety ground, and the other is attached to the conductor under evaluation.
  • If you need to isolate the electrical insulation on the test lead and you have more than two leads, ground the others and connect only the last cable.
  • Wait a brief while after applying a voltage to the test circuit before inspecting the current flow.
  • The current limit of the hipot tester can be exceeded if an excessive voltage is applied to one side of the device test cables and the insulation is damaged or deteriorated.
  • Since you’ll be dealing with both alternating current (AC) and direct current (DC) circuits, you should know how the hipot techniques are implemented for each.
  • A ramp time is unnecessary for an AC hipot exam.
  • The requirement to discharge the test instrument or cable once testing is over is eliminated in AC testing, and both voltage polarities can be checked simultaneously.
  • While AC hipot testing is more trustworthy than DC testing, it also exposes the operator to greater danger.
  • Lower-power devices can be used for DC testing, reducing the risk to the operator and the workload on the testing apparatus.
  • This means that while assessing voltages and currents using a DC tester is less dangerous and more cost-effective than with an AC tester, it is also significantly less accurate.
  • DC testing procedures for device safety certification are accepted by a much smaller number of safety bodies.

About Blake Sutton

Blake has worked as an electrician for over 10 years, receiving his Journeyman Electrician license in 1998. Looking to take his professional electrical career further, in 2008 he received his Bachelor of Science in Electrical Engineering (BSEE) from the University of Texas in Austin. Blake now works full time as an electrical engineer, specializing in power systems.