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Calibrating Earth Loop Testers

According to the QLD Electrical Safety Act 2002 -  Section 18 - (2)(b) : if a testing instrument can not be visually confirmed as being correctly functioning and safe — that the instrument is tested at least every 6 months to ensure it is in proper working order.


Loop Resistance measurement
Line Impedance Measurement
Line Voltage Measurement


To calibrate a Loop tester first the loop impedance of the supply must be known, then several known values of resistance must be inserted in the loop to increase the loop resistance so the tester can be calibrated at several points.  The value displayed on the tester can then be compared to that of the known value of the resistor plus the loop resistance of the supply.



Ensure your equipment is in specification so that the loop impedance testing you do is conducted in accordance with AS/NZS 3000 "Electrical installations - Wiring Rules "


All measurements are traceable to national and international standards via a registered NATA laboratory or a mutually recognised international testing authority. (See NATA’s International Activities