reasons for high zs?

Robo · Jul 11, 2011

Tnc-s install. with a ze of 0.31. Im gettin a high zs of 44.1 on kitchen lights. All lights have earth conected. Does this sound like a loose earth or faulty jb buried somewhere?? Iv repalced fuseboard and all bonding and earthing meet regs. I understand its RCD protected so ok but id like to get the reading down. Thanks

Dunc · Jul 11, 2011

What was your R1+R2/R2 readings for that circuit?

LlandrilloSpark · Jul 11, 2011

Do an R2 test from the same place you measured Zs,that may be a good starting point

telectrix · Jul 11, 2011

agree^^^^ as yet you don't know if it's R1 or R2 that's causing the high reading. could be a screw tigtened in the insulation, making a high resistance connection. also, make sure you haven't got a crossed polarity somewhere.

Deleted member 26818 · Jul 11, 2011

Or even worse, a cross polar bear.
They weigh 800kg you know....

MarkieSparkie · Jul 11, 2011

You did all of your dead tests before re-energising the installation? ... I hope! :frown2:

telectrix · Jul 12, 2011

if R1+R2 read OK, there's the possibility of the MCB causing the high reading, due to it's internal components.

Dunc · Jul 12, 2011

If the dead tests are good (low R1+R2 values) and the Ze is good but you still get high Zs readings it could be your meter playing up. I know on the 'no trip' loop tests noise on the supply can give you some right odd readings. Had this before and had to calculate Zs as the meter wouldn't give a accurate reading.