Live - Neutral reverse from plug in tester

The martindale style testers are a good start, but double faults often bring up a misleading code. However, something is wrong.

Do you have a meter that can measure volts, and a long enough wander lead to reach something you can be sure is solidly earthed ?

If so just verify the L-E and N-E voltages, .and then the CPC to E voltage. I suspect all will be revealed, and you may have two things wrong that may well be related, confusing the tester.

And do not rule out a hidden joint box in the middle of what you assumed was one cable.

And reverse polarity sockets are not unknown either, I think there were a few mentioned some years ago with the markings the wrong way round on the back!!

Mike.

The mysterious inner workings of a 13 Amp socket tester.

Those testers are no substitute for the traditional ring tests and IR.

If the tester plugs have an illuminated indicator showing L-N reversal it must be because the light connected between N and E is being supplied by a Voltage difference between  N and E with regard to the opposite terminal pin of the tester plug. So either E has a raised potential, or N has a raised potential. There is a potential difference between both. Why? Needs further investigation.

Z.

• The CPC could be live.
• There could be two breaks in the neutral with an appliance plugged in between the breaks.
• The live and neutral could be be reversed.

 

Yet taking off the outlets, the cables are connected correctly and live tested live in its correct position 

The problem must be with the N or E then.

Z.

A bedtime story,

Once upon a time…

IET Forums - Reverse Polarity At All Sockets (theiet.org)

Z.

hi thank you all for replies, there all as i guessed, so when allowed will do all thats recomenend by you Taking ring out of consumer unit to do full circuit tests of insulation then R1 -R2 tests and then use  a tone generator to see if any fixings local to faulty outlets pick up the tone in case a fixing has pierced cable but not enough for RCD to trip, unlikely but feasably possible. 

Its going to be a long job. my findings i wil publish here but may not be for a few weeeks. Having left the two dodgy outlets unuseable to occupier.

Mikesparky: 
 

hi thank you all for replies, there all as i guessed, so when allowed will do all thats recomenend by you Taking ring out of consumer unit to do full circuit tests of insulation then R1 -R2 tests and then use  a tone generator to see if any fixings local to faulty outlets pick up the tone in case a fixing has pierced cable but not enough for RCD to trip, unlikely but feasably possible. 

Its going to be a long job. my findings i wil publish here but may not be for a few weeeks. Having left the two dodgy outlets unuseable to occupier.

L-N 240 vlts. L-E 185 vlts; N-E 55 vlts, indictaes i think that somehow L is leaking across to E somewhere local, i think a plastered in joints are suspect. Its odd why RCD dont trip but maybe reduced voltage in middle of circuit is not enough milli amos leakage to trip 30ma RCD at board.

Have not had chance yet to perform proper tesing with insulation and R1-R2 tests. At least no local metal work like rads are reading this 55vlts to a N   point. and all oultes have 240 L-N voltage so no under volts present for appliances. I know telephone line operate arounf 50 volts and IEE regs recognise that 50 volts or under are not considred danger to life. But this circuit is not at an acceptable condition to be left at fault. still waiting for opputunity to test correctly.