Insulation resistance test

With the insulation resistance measurement the ohmic resistance of the insulation of a device is determined. It is measured between the live parts and housing parts or between different internal potentials.

As test voltage a DC voltage with 500 V DC is usually used. In practice and according to some standards often higher or lower test voltages are necessary. The permissible limit values are determined as well in the respective regulations for the product to be tested.

The insulation test can be carried out both at electrical equipment of protection class I and at devices of protection class II and is to ensure that no too high leakage currents occur in the DUT. If the insulation resistance of a device is too low (and possibly a ground bond fault exists) there may be high touch voltages on metallic parts such as the housing of the device. In case of contact the so-called "touch current" would flow over the human to the ground which can be life endangering in case of devices of protection class II.

The design of the voltage source of SPS electronic for this test is safety current limited. The maximum permissible current is set to 12 mA DC. By adhering to this limit value no additional safety precautions are mandatory despite the high voltage during insulation testing. Usually the insulation resistance test is performed on the de-energized DUT. However tests can also be realized under operating voltage. The insulation resistance test is required both in the routine test as well as in repeat and repair tests. However it may also be omitted or – in various standards – be replaced by the hipot test.

At SPS electronic you will find the appropriate insulation device for each requirement. Starting with the possibility of a mobile test application to the stationary use and up to integrated network operation our test devices are ideally designed for all applications. All devices are also intuitive and easy to operate.

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