ze testing - high current or no trip

[BES]

Testing for cu change .Customer had eic for 2 wy rcd protected cu fitted for kitchen sockets when refurbed a year ago. no prob but noticed the ze had been put down as 0.41(tncs) bit high so i tested on high current as always 0.21 changed to no trip 0.42. ive never test ze on no trip as high current gives a more accurate value.
i just wondered what setting others use when testing ze.
cheers
neil

 

[Risteard]

Not sure why you'd want to test Ze on no-trip loop setting. Doesn't make a lot of sense.

But I agree with you that non-trip loop can give sky-high readings at times.

 

[BES]

Exactly i can only think that the person who took the reading for kitchen refurb must have had his tester on no trip as when i took measurement on no trip it was 0.42 approx the same. Wouldnt you query this if you got. Such a reading on a tncs. As well as that the value of main fuse was incorrect and all the schedule of inspection items were tick including selv/pelv not a 12v in the house and some items u wouldnt except to be applicale in domestic. This was filled in by a niceic fully approved company looks like the certs were filled in before job was done

 

[Deleted member 26818]

Even if there were an upfront RCD, you wouldn't use the 'No trip' setting for measuring Ze, as you would take the reading on the feed side of the RCD.

 

[Richard Burns]

Ze can never need the no trip setting, though I did not realise it could make such a difference, I thought it was just a little bit high.
I would only do it If I was rechecking later and forgot to change the setting!

 

[BES]

exactly the reason i asked queston was result on eic for kitchen obviously person who tested it stll had tester on no trp when checking ze but wouldnt you realse something bt odd with ze being 0.41 on a tncs and also the pfc on eic was 1.1ka a result you would get from a much lower reading of ze. just thought i was a along with the other mistakes on cert is a bit poor.