Application Note www.megger.com Test connections Follow mandated safety procedures when connecting and disconnecting to an asset Please note that testing at these voltages can be very dangerous unless you take the necessary precautions, these include but are not limited to: • Correct use of PPE e.g. electrically certified safety boots, safety gloves etc. • Making sure the equipment has been discharged and safely connected to earth/ground • Making sure that the test subject and the equipment are isolated to make the test as safe as possible • Test with a voltmeter before proceeding to make sure there are no hazardous voltages present • Visually inspect all equipment for damage/faults before any testing Insulation testing an arrester must be done based on its rated voltage. So, always test with at least 50 % of the rated voltage no more than 120 %. For example, a 10 kV rated arrestor can be tested with at least 5 kV and no more than 12 kV. This is necessary because this is the range where an arrester’s resistance is constant while also being a high number. Figure 4: Connections for testing a surge arrester using an insulation resistance tester
Previous page: Artikel om överspänningsskydd: Insulation resistance [2 / 5]
Next page: Artikel om överspänningsskydd: Insulation resistance [4 / 5]
