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Product category: Stand-Alone Instruments
News Release from: Seaward Electronic | Subject: Earthing conductor testing
Edited by the Electronicstalk Editorial Team on 07 December 2006

Current thinking on testing protective
earthing

Jim Wallace, research and technology manager at Seaward Electronic, looks at the merits of using 25A and 200mA currents to test protective earthing conductors in electrical and electronic appliances.

Jim Wallace, research and technology manager at Seaward Electronic, looks at the merits of using 25A and 200mA currents to test protective earthing conductors in electrical and electronic appliances Debate in the appliance industry on the most appropriate test current for checking the integrity of the protective earthing conductor has been around for many years

Historically a higher test current of 25A has often been favoured on the premise that it will best detect any damaged conductors present.

In addition, when analogue instruments were widely used for low resistance measurement, it was often necessary to use high test currents to produce sufficient voltage drop across the sample to generate the necessary needle deflection.

With modern electronics this is no longer necessary and more recently, given the growth in popularity of portable hand held test instruments, others have come to prefer a lower test current of 200mA as a means of eliminating any risk of damage to the equipment under test.