Just a warning to all those who think a device has failed the protective earth resistance test, it may not have failed but contain an inductor in the earth connection!
Many commonly used test instruments on the market, even new units, that use an AC source for the test current can give incorrect readings when an inductor is present in the earth connection (as used for EMC). This is a known issue with many Fluke Biomed meters as well as the Rigel 266. Those meters that use a DC test current, such as the Rigel 288 and GMC Secutest SIII, do not exhibit this problem.
One solution is to try a different test current, if available, on the tester to see if a lower reading is obtained. This lower reading is most likely the correct value and not the higher or failed value!
It should be noted that this problem is not related to overcoming contact oxidisation and is purely a error in the meters measuring circuit when an inductor is present in the earth connection.
