Trip reading!!!

[Wardy35]

Whilst carrying out a Earth Loop impedence test to acquire the Zs values i kept getting a trip reading on the 1st floor/ground floor lighting circuits and also the the two shower circuits that were in the house. I had no problems with the socket circuits and the kitchen ring main. All light switches were off and all bulbs removed, i was using a megger 1500 series multitester.
Anyone got any suggestions as i did not get to see my mentor before the working day ended.
Oh and the RCBOs did not trip.
Regards
Wardy

 

[Guest123]

Were you using the three leads for Zs testing with the megger, and did you have a good contact on the conductors???

 

[Deleted member 9648]

The tester cant have been picking up a voltage....Either there was no voltage present,poor contact on probes,or jack plugs not fully inserted into meter...(had this with my new megger earth loop,you have to ensure the leads are fully pushed home)

Edit...another thought,if you were two lead testing and there was no earth present presumably the meter would not register a voltage,have you verified the continuity by R1R2 tests first?

 

[Wardy35]

Wasnt using three leads but had good contacts.

 

[Wardy35]

I checked all that, ie the megger. I even went around the house again to make sure all switches were off and bulbs out.
I left the house scratching my head.

 

[Guest123]

For the 'no trip' loop test using a megger MFT you need to use the three leads i.e neutral aswell.