Neutral Earth Loop Impedance Testing.

This would blow faulty connections apart and raise the potential on the metal parts of the installation to around 240 volts.  So potentially lethal to any occupants in the building. 

And this is why the voltage limited NE test setting is a safer way to verify rusty conduit and so on, and does have the advantage of finding an earth wire hanging by a single thread that might be missed by a modern low current tester.

Although I would agree with Geoff, be very aware that this is a museum piece, and it's behaviour on a faulty installation may not always be safe - another example is that  those solder link fuses are not going to handle a high PSSC supply.


By all means restore it to operation, but reserve it for a bit of fun on installations that you have already tested. Rather like driving a steam traction engine or using a wind-up gramophone, remember it's age and treat with care,

This would blow faulty connections apart and raise the potential on the metal parts of the installation to around 240 volts.  So potentially lethal to any occupants in the building. 

And this is why the voltage limited NE test setting is a safer way to verify rusty conduit and so on, and does have the advantage of finding an earth wire hanging by a single thread that might be missed by a modern low current tester.

Although I would agree with Geoff, be very aware that this is a museum piece, and it's behaviour on a faulty installation may not always be safe - another example is that  those solder link fuses are not going to handle a high PSSC supply.


By all means restore it to operation, but reserve it for a bit of fun on installations that you have already tested. Rather like driving a steam traction engine or using a wind-up gramophone, remember it's age and treat with care,