The majority of socket testers will only tell you if the earth is connected, and can indicate a 'safe' dangerous earth impedance value as bad as 10kΩ or higher. The Martindale EZ150 will indicate an open earth above 500Ω, and will indicate low/high voltages and perform a socket test as well.
Earth loop impedance indicator
Non-Trip earth loop
LED indication
Power consumption 1.6W
Power source 230V
Dimensions 65 x 65 x 50mm
Like all other indicators this unit cannot detect common earth and neutral or earth neutral reversal,
I got one of these following an episode in which all of the metalwork in our house became live when rodent damage to cables resulted in protective cables becoming partially disconnected from earth and live being shorted to the protective cables. To say this was a highly dangerous situation is an understatement. After the fault was repaired, I wanted an easy to use device that would detect whether the earth was "good enough". This socket tester does exactly that. You plug it into any socket and in a few seconds it reports on the health or otherwise of the circuit and also provides an indication of how good is the house's earth. Just what I needed. I'll use it from time-to-time just to confirm that things are remaining in a safe condition.
