Optical damage in earthing measurement

Safety tests are essential to ensure that products meet all requirements and specifications before they are put on the market. One of the important tests we carry out is the earthing measurement. This measurement is usually performed with a high current of 10 or 25 amps and a low voltage of 6 or 12 volts. While this is an effective way of assessing the earthing performance of a product, the welding principle created at the high current levels can lead to optical damage to some test products.

What is grounding measurement and why is it important?

Earthing measurement is a test performed to measure the resistance between the earthing system and the product. Its purpose is to ensure that the product is properly earthed, which matters for the safety of electrical equipment and the protection of users from electric shock. By measuring the earth resistance, we can assess the integrity of the earthing system and identify potential problems.

The problem of optical damage at high measurement current

When making grounding measurements with high current levels, the welding principle can occur, where damage on the surface of the test product can occur. This welding principle occurs due to the high current density occurring at certain points of the on. As a result, optical damage may occur, such as discolouration of material. This is particularly detrimental to products that need to maintain an optically flawless surface, such as lighting, displays or housings of electronic devices.

How to prevent optical damage?

Fortunately, a few precautions can minimise optical damage in high-power tests. Here are some suggestions:

Use of appropriate test points: Identify vulnerable areas of the test product and ensure that test points are strategically placed. Avoid placing test points on sensitive surfaces or areas prone to optical damage.

Before starting a measurement, make sure one has a good connection, the placement of the PE probe is important.

The video below shows an example of arcing on during grounding measurement