Live Neutral reverse?

Electrisco-pops

I was working in a friends house yesterday and when I tested the sockets with my socket tester it was beeping indicating live neutral reverse.

It is a very old house and alot of work has been done on it over the years. He told me that has been no electrical problems in the house so I walked away happily.

Can anyone explain what exactly are the consequences of this and how it happen?

meercat

i wouldnt be too happy
among other problems anything connected to socket(appliances lamps )will be switching the neutral and may have a constant permanent live at the bayonet cap
did you check the consumer unit/fuse box to see where reverse polarity is happening
if it is at consumer unit/fuse box then neutral is protected by fuse/tripswitch and if this blows it does not interrupt the live to socket outlet
have you checked lights cooker immersion
dont leave as it is
get a competent sparks to check it out and FIX it

Bruthal

Reverse polarity wont show up in the operation of any electrical items in a house. They will all work as normal, but this does not mean its ok.

Did you only check one socket?
Check fusebox as meercat says to see if its just a single socket or socket circuit thats reversed, or is it at the feed into the board. It could be just that one socket.

Another problem with reverse polarity at a socket is that if there is a Neutral-Earth short or fault in an appliance, this in now a Live-Earth fault except there is now no plug fuse in the fault path, and if the neutral earth is reversed feeding the fuse box then there is no fuse at all before the esb one.

Needs the sparky alright.

M cebee

prob the 'final circuit' is reverse polarity then

or could be part of the circuit


some sockets are DP so switching off may isolate
but the L-E fault backs up to the next protective device wired correctly

ntpm

I have been called to new installations (which were tested:rolleyes: and certified).which have had some sockets incorrectly wired.
The cabling was correct from the consumer unit but possibly the apprentice was left to make final connections to socket terminals and managed to get live and neutral mixed up:rolleyes::rolleyes:.

Quick check is to turn power off open up socket and visually check terminal labeling and colour of cables.

And if you have a multimeter, switch power back on to actually check the cables for voltage for and polarity.
L to E = 230v
L to N - 230v
N to E - 0v ( but could go upto 30v ish still ok)

Also recently went to a house where the original lights cabling was red (live) and black (neutral) and extra lights were added BUT with new brown (neutral) and blue( live) cabling..
An innocent mistake or didn/t check polarity after connection either way lights will work but not safe.

RoundyMooney

I'd be very wary of walking away from something like that, if I was working there in an electrical capacity (I assume you weren't, OP!).

He needs the whole installation checked out by a competent person asap!

Electricman999

I agree you better get the entire electrical installation checked out by a component time served electrician before somebody gets electrocuted or the place burns down.

Make sure they are RECI Or ECSSA registered & carry insurance

pieface_ie

As already said its not a good idea to walk away from something knowing its not operating as should, do in a domestic installation a L N reverse appliances will still "function" as normal but not ideally safe.

It would be easy enough to recify, do time consuming, but definatley do not leave it.

Bruthal

ntpm wrote: »

I have been called to new installations (which were tested:rolleyes: and certified).which have had some sockets incorrectly wired.
The cabling was correct from the consumer unit but possibly the apprentice was left to make final connections to socket terminals and managed to get live and neutral mixed up:rolleyes::rolleyes:.

I never laugh at mistakes like that in final connections, anyone could do it, its easy to get distracted etc even though most might say `not me`.

A new installation with socket wrong should be found if properly tested, it only takes a few minutes to do socket polarity tests. But again, mistakes are made in every aspect of everything, testing included id say. As i said before, an installation thats certified does not mean its done to a good standard either. But it still has to be done to give some sort of standard.

Bruthal

pieface_ie wrote: »

As already said its not a good idea to walk away from something knowing its not operating as should, do in a domestic installation a L N reverse appliances will still "function" as normal but not ideally safe.

It would be easy enough to recify, do time consuming, but definatley do not leave it.

O` no not the text spelling:pac:

M cebee

every socket should be checked with loop-impedance tester after energizing installation imo

that's the way i do it anyhow

i have more faith in live testing than dead tests

Bruthal

Yes cant argue with that. The more points tested the more reliable the results.

M cebee

i see reverse-polarity all the time when working on jobs


it may be unrelated to the job you're doing -and customer may not want to fix it

but i always make them aware anyhow

ntpm

M cebee wrote: »

every socket should be checked with loop-impedance tester after energizing installation imo

that's the way i do it anyhow

i have more faith in live testing than dead tests

Loop impedence test, if carried out properly will also show the integrity of ring circuits and earths in radial circuits.... I know many guys who " carry out test" that don't know how to properly evaluate the readings.

M cebee

your Zl must be within the limit specified for the mcb or fuse and type of circuit


how will it verify the ring circuit?


you might have parallel fault paths when testing Zl at sockets so it can't always veriify the cpc

ntpm

M cebee wrote: »

your Zl must be within the limit specified for the mcb or fuse and type of circuit


how will it verify the ring circuit?


you might have parallel fault paths when testing Zl at sockets so it can't always veriify the cpc

Sorry fruedent slip.. Loop impedence test = using suitable equipment/ megger for reading loop impedence, insulation resistance, ..etc.



BEFORE SUPPLY CONNECTED
1 continuity of protective coductors, including main and supplementary bonding
2 continuity of ring final circuit conductors, including protective conductors
3 insulation resistance test
4polarity by continuity methode
5 earth electrode resistance, when using an earth electrode resistance tester

WITH THE SUPPLY CONNECTED

1 re-check polarity
2 earth electrode resistance using a loop impedance tester
3earth fault loop impedance
4 Prospective fault current measurement
5 functional testing

M cebee

you've lost me


'earth electrode resistance' testing not required for tn-c-s unless i'm mistaken

M cebee

M cebee wrote: »

you've lost me


'earth electrode resistance' testing not required for tn-c-s unless i'm mistaken

ok - i think i get the freudian slip:)

ntpm

M cebee wrote: »

you've lost me


'earth electrode resistance' testing not required for tn-c-s unless i'm mistaken

I work Ireland and in England.
I tend to carry out test to ETCI but also to IEE regs and BS that may not be done here on regular domestic installation.
I often have to test TT systems in rural/ agri farm areas. This is to ensure the electrode resistance is not so high that the voltage from earthed metalwork to earth exceeds 50 V where an RCD is used or multiple rcd fed circuits.

M cebee

ya i know:)

i'm familiar with it

ntpm

M cebee wrote: »

ya i know:)

i'm familiar with it

>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Just to go back to the original post

Live / Neutral Reversed:

Preconnection test to check continuity of ring final circuit conductors, including protective conductors.
would have shown if Live was continuous ( and connected to corrected to correct terminal on socket) and as the test measurement /readings should taken at each socket in a ring circuit it can be determined if the ring is complete.

Therfore any house that has been fully tested (properly) should not have any polarity reversal.

.G.

Given that we've all probably seen dodgy wiring and I'm sure we've all asked ourselves how it couldve passed testing and verification but who is to say tests are even done by people who do the dodgy wiring.

Lets be honest,in the age of self certification people can say they tested,fill out the paper work off the top of their head and never actually do the tests.

There are several apartment blocks in the north of this city completed in 2006/7/8 and consisting of hundreds of apartments that have never had any testing done on them.Even more laughable given said contractors current elevated position in the electrical world,but I must stay tight lipped on that,friends in high places etc

Self certification should never be allowed IMO.For every good contractor out there who'd do the test,theres probably one who said he did but didnt,particularly in the boom years.

M cebee

i'm of the same mind:)

inspection of every new installation is the only way-let customer pay

-of course anything can and will happen after


seems to be a lot of non-sparkies registered especially with ecssa if i'm not mistaken

and certs being sold- some registered contractors even seem to think it's allowed:mad:

Bruthal

ntpm wrote: »

>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Just to go back to the original post

Live / Neutral Reversed:

Preconnection test to check continuity of ring final circuit conductors, including protective conductors.
would have shown if Live was continuous ( and connected to corrected to correct terminal on socket)

Yea but the live can be shown to be a complete continous loop but still have a socket reverse connected, this would not show in a ring continuity test, unless the socket had a blue connected to a brown. But its more likely the 2 browns would be together in the neutral terminal and the 2 blues also together in the live terminal, so the socket is reverse polarity, but the ring still has complete continuity. Only a polarity test at each socket will show positively the polarity is correct or incorrect if thats the case.

.G.

M cebee wrote: »

i'm of the same mind:)

inspection of every new installation is the only way-let customer pay

-of course anything can and will happen after


seems to be a lot of non-sparkies registered especially with ecssa if i'm not mistaken

and certs being sold- some registered contractors even seem to think it's allowed:mad:

Indeed.Even the best make errors, but the best are likely to be well outnumbered since the boom making compulsory independent testing a must in my view.

If a contractor wasn't arsed doing them during the boom years cos it was too time consuming/costly then he's even less likely to be arsed doing it now when everybody is watching their shillings.

M cebee

i've no problem with mistakes
i've made loads of them:)

everybody(including me) would have to pull their socks up on new work

FoxT

Can anyone explain what exactly are the consequences of this and how it happen?

Reading through the thread here it is clear that there is lots of technical advice available. However , to answer the questions:

1- Live-neutral reverse connections happen accidentally.

2- Live-Neutral reverse will not affect the operation of any appliances, but it is a bad thing for safety reasons. Some examples are:

If you have an appliance connected to a switched socket & you switch it off at the socket, there is still a live supply connected to the device.

Bayonet fittings (light bulbs etc) will remain live even when they are switched off.

if you have an appliance that develops a short circuit or overcurrent fault, then the fuse will blow on the Neutral side. Thus, you will still have a live feed to the appliance itself. this could be dangerous.



The good news is that it is easy to fix. I recommend you alert your friend to the problem & recommend he get it sorted.

- FoxT

.G.

M cebee wrote: »

i've no problem with mistakes
i've made loads of them:)

everybody(including me) would have to pull their socks up on new work

Exactly meaning those mistake we all have made would be less likely to damage someone or something.

It will never happen though unless current big wigs of the industry are involved in making some money from conducting or organising them.I've seen inspections by both RECI and the ECSSA and they amounted to nothing more than the inspector and contractor having a chin wag about family,the industry etc.

If those examples are the norm then god help us all

M cebee

FoxT wrote: »

Reading through the thread here it is clear that there is lots of technical advice available. However , to answer the questions:

1- Live-neutral reverse connections happen accidentally.

2- Live-Neutral reverse will not affect the operation of any appliances, but it is a bad thing for safety reasons. Some examples are:

If you have an appliance connected to a switched socket & you switch it off at the socket, there is still a live supply connected to the device.

Bayonet fittings (light bulbs etc) will remain live even when they are switched off.

if you have an appliance that develops a short circuit or overcurrent fault, then the fuse will blow on the Neutral side. Thus, you will still have a live feed to the appliance itself. this could be dangerous.



The good news is that it is easy to fix. I recommend you alert your friend to the problem & recommend he get it sorted.

- FoxT

stop please:pac:

Electricman999

M cebee wrote: »

i'm of the same mind:)

inspection of every new installation is the only way-let customer pay

-of course anything can and will happen after


seems to be a lot of non-sparkies registered especially with ecssa if i'm not mistaken

and certs being sold- some registered contractors even seem to think it's allowed:mad:

I AGREE WITH YOU M cebee
The celtic tiger might of brought prosperity to the few big boys.
It destroyed the electrical trade with extremely poor qualified apprentices with Electricians Qualifications in pockets.
MAY GOD HELP US ALL AND THE SUCKERS WHO PAID DEARLY FOR RUBBISH INSTALLATIONS & MATERIALS.

ntpm

Electricman999 wrote: »

I AGREE WITH YOU M cebee
The celtic tiger might of brought prosperity to the few big boys.
It destroyed the electrical trade with extremely poor qualified apprentices with Electricians Qualifications in pockets.
MAY GOD HELP US ALL AND THE SUCKERS WHO PAID DEARLY FOR RUBBISH INSTALLATIONS & MATERIALS.

Totally agree with M cebee and Electricman999.


IMO Self regulation is No regulation as far as Dodgy Contractors (electrical, gas, oil, plumbers, builders) are concerned,,,
Have'nt we learnt any thing from the Banks.

SuperG makes a good point...

Although the certs that should be filled out with every circuit / protective details/ fuse ratings and corresponding readings I have been involved with RECI and ESCAA certs and they only ask for overal readings etc..

How many times have you seen each of the boxes filled in with actual readings.

They should make you do a print out of the test readings via the machine to actually show times and dates, calibration details.

This would ensure contractors are not just putting in generic figures
that they know will pass.

If you are suposed to do test then they should be fully documentated and be able to stand by them.

ntpm

robbie7730 wrote: »

Yea but the live can be shown to be a complete continous loop but still have a socket reverse connected, this would not show in a ring continuity test, unless the socket had a blue connected to a brown. But its more likely the 2 browns would be together in the neutral terminal and the 2 blues also together in the live terminal, so the socket is reverse polarity, but the ring still has complete continuity. Only a polarity test at each socket will show positively the polarity is correct or incorrect if thats the case.

1. Continuity of Protective Conductors
I would plase a strap between phase and protective conductors in the distribution board and test between phase and earth terminals at each socket outlet in the circuit.
This should confirm that my live have been connected to the live terminal only.


2. Continuity of Conductors in Ring Final Circuits
Taking appropriate readings at the socket outlets;
On a ring circuit you should see a progressively increase in value as readings are taken towards the midpoint of the ring, then progressively decreasing towards the other end of the ring.
An error in this respect will be apparent ring.


I am always up to being corrected if the above is incorrect... Everyday is a learning day for me.:o


One of my earlier points in a post is taking reading is one thing... knowing and interpretating what they mean and show is another thing.

Electricman999

ntpm wrote: »

Totally agree with M cebee and Electricman999.


IMO Self regulation is No regulation as far as Dodgy Contractors (electrical, gas, oil, plumbers, builders) are concerned,,,
Have'nt we learnt any thing from the Banks.

SuperG makes a good point...

Although the certs that should be filled out with every circuit / protective details/ fuse ratings and corresponding readings I have been involved with RECI and ESCAA certs and they only ask for overal readings etc..

How many times have you seen each of the boxes filled in with actual readings.

They should make you do a print out of the test readings via the machine to actually show times and dates, calibration details.

This would ensure contractors are not just putting in generic figures
that they know will pass.

If you are suposed to do test then they should be fully documentated and be able to stand by them.

RECI & ECSSA Have now been taken over by CER right.
I put to you who are CER a group of unqualified suits dictating the terms how RECI & ECSSA members carry out their trade.
With no on site experience, firsthand knowledge, experience of the industry or trade.
Does a civil servant in the HSE tell a surgeon how to carry an appendix operation?

ntpm

Electricman999 wrote: »

RECI & ECSSA Have now been taken over by CER right.
I put to you who are CER a group of unqualified suits dictating the terms how RECI & ECSSA members carry out their trade.
With no on site experience, firsthand knowledge, experience of the industry or trade.
Does a civil servant in the HSE tell a surgeon how to carry an appendix operation?

Bring on the revolution!!

Electricman999

National trades licensing system on the way in Ireland
A national licensing system for priority occupations including the electrical industry
This development of a national trade licensing system in the context of its broader agenda for regulatory reform.

2011

IMO Self regulation is No regulation as far as Dodgy Contractors (electrical, gas, oil, plumbers, builders) are concerned,,,

+ 1
I have made this point several times

I think the solution is simple. IMHO an independent body should certify all electrical work. I think that the advantages of this would include:

1) All work will be carried out to the correct standard
2) All contractors will be quoting on a level playing field as no regulations can be broken
3) There will be more demand for skilled electricians and apprentices. This in turn would improve pay and training for those that take a bit of pride in their work.
4) Less more for the cowboys that fuel the race to the bottom!

Electricman999

2011 wrote: »

+ 1
I have made this point several times

I think the solution is simple. IMHO an independent body should certify all electrical work.!

Sorry who are the IMHO?????

2011

Sorry!

2011

IMHO = In my humble opinion!

Bruthal

ntpm wrote: »

1. Continuity of Protective Conductors
I would plase a strap between phase and protective conductors in the distribution board and test between phase and earth terminals at each socket outlet in the circuit.
This should confirm that my live have been connected to the live terminal only.

What if the phases were connected to the earth terminal and earths to phase terminal in socket? Would the above not show the same reading? Unlikely to happen, but we cant assume.

Although i have to say i would of thought once the pre energised socket circuit tests were good (continuity, insulation etc) then the polarity test can be done with it powered on. Whats the advantage of doing a pre power on polarity test of each socket? Even the plug in tester does not confirm its right, earth and neutrals could be swapped and the polarity tester may not trip RCD, it just confirms the live is right.
But once the RCD tests trip the RCD and the polarity reading says polarity is correct then it is correct.

I am always up to being corrected if the above is incorrect... Everyday is a learning day for me.:o

As for all of us. Although we may reach a certain age where it starts to reverse:)

ntpm

Point taken...
thanks.

"As for all of us. Although we may reach a certain age where it starts to reverse "

grumpy old men..

Bruthal

Could connect a 9v battery to any socket L&N and RCD off, MCBs on and that would give polarity check to every socket pre-power with miltimeter on dc

ntpm wrote: »

Point taken...
thanks.

"As for all of us. Although we may reach a certain age where it starts to reverse "

grumpy old men..

Yes i can feel it happenin already, i must be old now:)

FoxT

M cebee wrote: »

stop please:pac:

what do you mean by that? Am I wrong about something here?

Bruthal

FoxT wrote: »

what do you mean by that? Am I wrong about something here?

It was all said already on the first page i think.

FoxT

I have re-read it.... oops - duh! dont know how I missed that, thanks.

M cebee

FoxT wrote: »

what do you mean by that? Am I wrong about something here?

you said it was accidental:)


-DP switched sockets will break both live conductors

- L-E short-circuit will trip rcd or nearest protective device in phase/line conductor

- a hazard anyhow

Bruthal

M cebee wrote: »

you said it was accidental:)


-DP switched sockets will break both live conductors

- L-E short-circuit will trip rcd or nearest protective device in phase/line conductor

- a hazard anyhow

Well reverse polarity would be accidental would`t it,
How do DP switched sockets come into it, thats ok if every socket has them, the majority probably dont.
Once there is an RCD though its not a major hazzard alright, but in the house mentioned here by OP there probably is none.

M cebee

i was just clarifying that point-if they happen to be DP the switch will isolate


of course that's why why appliance isolators should break all live conductors always

anyhow-i would disregard the rcd-not to be relied on for L-E short-circuits in TN systems
-although it should trip-

Bruthal

Well in a reverse polarity earth fault scenario i would`t disregard anything and would hope the RCD would trip, but i know what your saying.

Bruthal

M cebee wrote: »

of course that's why why appliance isolators should break all live conductors always

Yes that would be a good idea.

carrick

The fact that someone would walk away from that tells you alot about where the trade is at over the last ten or so years.I heard the term boom sparks being used last week very apt(not in a good context).