Megger LT3 MK2 Tester

[Jon999]

I’m trying to find an instruction manual/wiring diagram for an old Megger/Evershed Vignoles LT3 MK2 Earth Loop tester ….any info would be appreciated….

The L-E and L-N indic.lights are self explanator,but how is the probe connected?

if the tester were plugged into a socket and the probe was touched onto a remote metallic earthed device would it register the validity of the earthing of the device?

 

[bill01803]

Yes, that is what the probe is for

 

[timhoward]

From memory it tests the socket earth if a probe isn't connected, and uses the probe instead if you plug it in.
These days in most cases it will instantly trip an RCD if you use it, unless you use an socket that isn't RCD protected.

Look at youtube - "John Ward" for videos on earth loop impedance testing in general.

For how to test an RCD protected circuit with a high current test, this video shows the principle:

It would be hard to do safely with your particular machine though.