Protective conductor resistance test devices

Typically, electrical products are connected to the power grid via power cords with plugs or terminal blocks. The " protective conductor test " therefore occurs between the PE of the power plug or the PE-connection clamp , and all connected metallic housing parts of the electrical product.

If an electrical appliance has multiple metal housing parts connected to the protective earth conductor , the proper functioning of the protective conductor must be verified individually for each housing part. If protective conductor connections are no longer accessible on the fully assembled electrical appliance, these connections must be tested during intermediate inspections while the appliance is still in production.

protective conductor test uncovers these errors.

• Interrupted protective earth conductor
• protective earth conductor s with too high an impedance, poor contact resistance
• Intermittent connections or poor terminal points of the protective earth conductor

How is the " protective earth conductor " tested?

In most cases, the protective conductor is tested based on its measuredohmic resistance. Alternatively, the voltage drop across the protective earth conductor can also be measured.

To determine the resistance or voltage drop, a high minimum test current must flow through the protective earth conductor , depending on the test standard. The test device sets the test current to the specified level and regulates it to a constant value.

The high- Test current s are intended to simulate a load on the protective conductor in order to “burn away” any weak connections that may be present. However, with typical test durations of one second, this usually does not succeed in practice, since it is virtually impossible for the contacts to heat up enough to burn away the weak connections within that time.

For precise protective conductor testing, the four-wire technology (also known as a Kelvin measurement, 4L, or 4W) is extremely important. Only this method reliably allows for the precise measurement of smallresistances in the mΩ rangespace measurement . The tester thus determines four-wire technology the voltage drop across the protective earth conductor and calculates the protective conductor resistance based on Ohm’s law.

The "good/bad" criteria.

Upper limit values for ohmic resistance or voltage drop are defined in standards. These limit values must not be exceeded under any circumstances.

protective conductor test AC or DC?

Test current , in most cases, is alternating current. However, in some applications—for example, when using long coiled connection cables—direct current can also be advantageous.

This is how the " protective conductor test " is conducted.

Whether manual, semi-automatic, or fully automatic: with SCHLEICH protective conductor testers, any testing task can be completed quickly and efficiently run.

Our test devices are all designed according to the "KISS principle". Following the motto: »Keep It Simple and Smart«. This principle serves as a guiding theme for all SCHLEICH products!

A manual test is performed using a protective conductor test probe. To do this, the operator manually moves the test tip from test point to test point. Despite the manual process, the test can be documented accurately. A typical application is the inspection of electrical products, control cabinets, and machines in accordance with the Machinery Directive EN 60204.

Partially or fully automated protective conductor testers or automatic protective conductor testers are suitable for the requirements of manufacturing facilities provide . For this purpose, the testers are equipped with a relay switching panel (relay matrix). These automatically route the test currents to the desired test points.

Test systems of this type have up to 1,000 test connections, depending on the application.

The requirements for a standard protective conductor test device.

Many national and international standards requiretest currents ranging from 10 to 30 A. These test currents can be set in steps on the tester. In addition, SCHLEICH also offers protective conductor testers ranging from1 A to 500 A AC/DCTest current .

SCHLEICH protective conductor test devices are based on over 30 years of experience. From the beginning, the measurement technology was not analog but always designed digitally. Fundamentally, the latest technologies are always applied.

This is how you find the right protective conductor test device.

The number of protective conductor test devices available on the market is large, and the quantity of configurable features is overwhelming.

If you intend to use your device under test exclusively for protective conductor tests with AC or DC run , a single-function tester is the best choice. It includes only the test method “protective conductor resistance.”

If the device under test also requires a more comprehensive safety and functional check, we recommend our combination testers/multifunction testers. These allow you to conveniently combine various test methods—such as protective earth conductor, insulation, and high voltage test —into a single tester. The fully automatic test method switching integrated into the tester ensures that no test leads need to be manually reconnected to the device under test during the test.

In addition, it is common to find a combination of safety tests and comprehensive functional tests. During the " function test " test, the test device also supplies the " device under test " with operating voltage to verify its electrical operating characteristics.

Thanks to the intuitive and convenient operation of SCHLEICH protective conductor resistance test devices, every Test is performed quickly, precisely, and cost-effectively.