Any electrical or electronic equipment and its components often deteriorate over time due to constant use, harsh environmental conditions, mishandling, misuse, or a combination of all these factors. This can also cause a range of other issues, including component failures, malfunctions, and poor performance. Other factors that also are contributing factors to the degradation of electrical appliances are air-suspended dust, accumulated grime, rust, and condensation. On top of that, without general design consideration, circuit modification, load adjustments are sometimes made, which further results in poor equipment performance. This is why periodic electrical testing, especially to detect certain device degradation is necessary.
A dielectric withstand test, or the ‘hi-pot test’, estimates the breakdown voltage at weak insulation points and verifies whether the insulation of a component is sufficiently strong enough to protect users from an electrical shock. The dielectric test consists of typically applying a higher than the normal operating voltage to the components to detect any defects and current leaks through the insulation.
Dielectric withstand (hipot) testing is a safe and most accepted way of ensuring that primary wiring and components are isolated from the safety ground. It is often combined with ground continuity testing so that the integrity of the safety ground between the appliance and the building ground is ensured. Although the manufacturer makes sure that any fault within the appliance is unlikely to occur, but if it does, then the mains power will be disconnected by the power breaker fast enough to avoid damage to the appliance.
There is also an insulation resistance test, which measures the resistance of the insulation. Before the high potential tests, it is imperative to do the insulation test to avoid any damage to the electrical insulation. While both tests have the same basic objectives, they are quite different. Continuity test checks to ensure that the current flows easily from point A to point B while the hipot test checks to make sure that the current would not flow from point A to another point B.
Hipot testers are designed to perform regulatory compliance tests for electrical systems. They come under the wide umbrella of the general category of electrical safety testing devices.
All hipot testers have a high voltage output and a return, which is wired to the chassis, and then connected to the ground wire of its power supply, which is then connected to the building ground. This is the primary line of defense against electrical shock to the operator. It is essential that the power outlet being used to supply electricity to the hipot tester is the three-wire type and is grounded in accordance with NFPA codes.
In case hipot tester grounding is not done correctly then the chassis of the device being tested could be at a high potential which will be risky and could give an electrical shock. Furthermore, with a poor ground connection, leakage current will not flow at all and the hipot tester leakage current limit may never be met and the test will fail.
Types of measurement performed by hipot testers following:
The parameters these devices can measure are AC and DC inputs and output voltages, AC and DC output current, resistance range, and insulation limits, etc. The type of test will determine the level of voltage that is applied during the test. Testers can also measure the resistance range and the insulation limit for a voltage range the insulator can hold. Most of the tests performed are time-based checks.
Hipot testers can work in manual, automatic or semi-automatic mode. Some test instruments are fully automatic and can be programmed to perform the tests and store the results without any human intervention. They can perform not just one but a series of safety tests automatically. Although automatic testing is the easiest one to perform, manual testing is sometimes preferred for close observation but needs an expert technician to be present during testing and make adjustments to the test parameters whenever necessary.
Some features for hipot testers are:
e2b calibration can perform repair, service, and calibration of all types of hipot testers to the highest industry standards while being reliable and cost-effective. Our verifiable services are unmatched in the industry. We provide NIST traceable calibration and issue calibration certificates and calibration labels to meet your requirements. We are registered with ANAB. We are also ANSI/NCSL Z540-1-1994 certified. We have the NIST Traceable Wide scope of ISO/IEC 17025 accreditation. Contact e2b calibration for more information.