Reverse Polarity

[pmoyne]

Need a sanity check, I have a customer issue... installed a customer supplied consumer unit as they had the supply brought into the basement, so 3 ciurcuits had to be extended etc tested it all issued certificates etc. all fine. however halfway through the day the customer asked when was i going to do the basement consumer unit. I said it wasn't agrred and i would not have enough time that day. however I agreed to move the meter tails as they would reach the new supply. I did this and did a direct ZS on the ring main and all checked ok.

They agreed to have me back in three weeks to do the basement consumer unit. the saturday night before going in on the Monday saying he didn't want me back, because his wife had a electric shock from the washing machine and had lost confidence, this was the 13th of march they then got and electrician on the 31st of March who said the meter tails had been reversed and this was horendous and had caused the electric shock.

Apart from various stories changing and they started off saying I have switch the live into the earth bar 1st, but have changed it to the polarity reverse, would this cause the plumbing to go live.

They are asking for money by the way...

any advice would be helpful.

 

[martysparky]

One polarity you wouldn't want in reverse!
All would be continually live except open double pole switches.

I don't understand what you are saying here:

I have switch the live into the earth bar 1st, but have changed it to the polarity reverse, would this cause the plumbing to go live.

Are you qualified? I ask this because if you dont know what makes water pipes live it makes me think such.

Otherwise, the customer could be scamming you... Have they shown you any new certs from the other electrician.

 

[Sav]

Hi,
If the meter tails were reversed, as in put in the wrong way round, you would know about it when you powered up the cu.
Have you checked your main earth , bonding etc. have you checked the continuity of the protectve conductors?

What sort of supply is it? TN-s, TNC-S ?

Best regards,
Sav

 

[martysparky]

Sav, I've never done this but when you say 'you'd know about it when you energized th CU' Makes me think I'll always triple check. I guess it would be better not to find out firs hand

 

[pennywise]

I always, always check my polarity on the supply side before throwing the main switch then a visual on all interconnected links between RCDs and bars.

 

[Sav]

Hi again pmoyne,

Can you explain again in a bit more detail about the live to earth reverse bit ???

Did you do, as pennywise and martysparky said, a visual inspection and triple checked connections, meter tails, main earthing etc ?

It may be a good idea to try to go back to the job and see what you done and what the new sparky has done as well. Maybe they are just trying to get some money off you !!
Sav

 

[chris gray]

right.. how could anybody worth their salt possibly get live + earth crossed over at a cu?
i think you would have great trouble getting a 25 into the earth bar and even if you did it would stick out like a SORE thumb

if the earthing arrangement was a certain one then yes a live - neutral reverse polarity on the main incomer would make things rather tingly.

 

[Sav]

Thats what I along with the rest of the guys, are trying to get our heads around.

I think it needs to be explained exactly what is connected to were and what is not !!

 

[pmoyne]

Yes qualified, didn't want to answer my own question. just making sure i'm not missing anything or a slight possiblity that other than there being an exsiting fault where neutral earth is connected this could happen.

cheers

Sorry, originally they said that i had swapped the live and earth over on the tails.

sorry really ****** about this. so typing in anger. apologies for the confusion

One polarity you wouldn't want in reverse!
All would be continually live except open double pole switches.

I don't understand what you are saying here:

I have switch the live into the earth bar 1st, but have changed it to the polarity reverse, would this cause the plumbing to go live.

Are you qualified? I ask this because if you dont know what makes water pipes live it makes me think such.

Otherwise, the customer could be scamming you... Have they shown you any new certs from the other electrician.

 

[martysparky]

I was thinking the same Sav but I have got to say Chris the directness made me Laff

 

[pmoyne]

The supply is TNCS, I bonded the earth and the water to the new supply. as all i did was move the tails from the old meter blocks to the new ones i didn't test each circuit, however i did do a direct Zs to check it was all working correctly and put a socket tester on. I didn't even open the old fusebaord as I was mindful that i didn't want to be responsible for it.


If the meter tails were reversed, as in put in the wrong way round, you would know about it when you powered up the cu.
Have you checked your main earth , bonding etc. have you checked the continuity of the protectve conductors?

What sort of supply is it? TN-s, TNC-S ?

Best regards,
Sav[/QUOTE]

 

[pmoyne]

Right then.

This is not proven and you have to take into consideration that this is a lie or a scam.

They claim the following.

Di was keen to contact you herself, but has mis stated the problem I'm afraid, it was in fact the 2 tails coming into the consumer unit that you had switched over in error, creating a horrendously dangerous fault to occur.


We asked a qualified (37 yrs experience) NICEIC registered electrician to investigate what had gone wrong with our system, and why Di had suffered an electrical shock. He found the fault within a few minutes, as the live and neutral tails coming into the basement consumer unit had been switched by you, at the end of the days work you did for us. You'll recall no doubt that you put the live power back into the old consumer unit after partially installing the new box, but as this was incomplete you put the tails back into the old unit - but critically you put them in the wrong way round. I can easily obtain written confirmation of this by the new registered electrician should you wish me to. He was shocked and appalled by your mistake, and was amazed that you hadn't performed any safety checks that could have quickly detected the problem, and averted the shock.






I think it needs to be explained exactly what is connected to were and what is not !![/QUOTE]

 

[chris gray]

do you have liability insurance?

 

[pmoyne]

yes, I have offered that they go through niceic but they seem reluctant.

 

[chris gray]

i would personally go round and speak to them and ask to speak to the other electrician, if youre concerned ring niceic yourself and ask their opinion

 

[Deleted member 9648]

If the earthing system is satisfactory and there were no other faults a reversed polarity would not cause a shock,a danger would only arise if a S/P mcb or switch was off for maintenance etc and a live would still be present at the appliance.
While this is a serious defect which should be picked up by testing and inspection prior to energising it may be worth asking them to explain how this could cause an electric shock if the appliance was just being used normally.

 

[pennywise]

May be wrong but didn't think a plug in tester could tell you whether N and Earth are reversed on a TNC-S system, think I read it on the packet of mine when I got it years ago.

 

[chris gray]

May be wrong but didn't think a plug in tester could tell you whether N and Earth are reversed on a TNC-S system, think I read it on the packet of mine when I got it years ago.

no martidale/plug in socket tester can do a n-e reverse test

 

[Deleted member 9648]

I thought he is accused of reversing the live and neutral??....not neutral and earth??

 

[martysparky]

If the earthing system is satisfactory and there were no other faults a reversed polarity would not cause a shock,a danger would only arise if a S/P mcb or switch was off for maintenance etc and a live would still be present at the appliance.
While this is a serious defect which should be picked up by testing and inspection prior to energising it may be worth asking them to explain how this could cause an electric shock if the appliance was just being used normally.

Good point. maybe worth asking if the customer was dripping wet or the washing machine was in a suitable location and if in a bathroom for example is it suitable for such location as per manufacturers instructions.

 

[Guest123]

I read the OP as being a L-N reverseal....not N-E???

 

[pennywise]

no martidale/plug in socket tester can do a n-e reverse test

Sorry my confusion Socket tester can't show reversed Neutral and earth. Only Neutral and live reversal

 

[martysparky]

yes, I have offered that they go through niceic but they seem reluctant.

Seems evasive then?

 

[pennywise]

I read the OP as being a L-N reverseal....not N-E???

I may have read it wrong

 

[volt-dropping]

THey waited 20 days with no mcb protection with only one major incident , with no safe running water without the use of vde 1000v gauntlets , none of the many polarity conscious electrical appliances exploded .

The lighting would appear unaffected and would still work in most cases but something would explode .

This may be vicious flannel at your expense some electric shocks from washing machines are static put the right clothes in and its a high rev static generator , i used to work in a clothes factory and the woman were always getting static shocks from fast spinning materials and always claiming it was mains voltage and painfull , remember electricity in any form terrifies the naive!!!

just another take on the situation

 

[martysparky]

I noticed a socket in reverse not so long ago whilst doing a job. Told the customer and they wouldn't let me touch it so they could get the guy to come back and prove what he had done directly. I would be thinking why don't they want you back to prove what you had done as now its only word for word.
One cert against another and is the other a family member? or as being evasive vested interest? or non existent?

 

[Deleted member 9648]

Sounds like shutting the barn door after the horse....you know the rest,...... but one thing this sort of thing brings home is the value of a full set of test results on a cert at the end of every job.With proof that the job was left in the correct state this sort of poo cant come your way.

 

[acat]

Dont give them any money back I think they are trying to have you over. If you are with the NICEIC they tend to treat verbal complaints with the contempt they deserve.

Your customer needs to put his complaint in writing for a start and name the other electrician in it inform them that you will be passing this complaint to your solicitor for action.


I doubt you will hear from them again.


Chris

 

[pennywise]

I now take pictures of all installs too, along with the test results it's a very strong augment.

 

[joethepudding]

Sounds to me like they are taking the P.. if there story is changing as you say.

never under estimate a customer faced with a bill they dont want to pay.

if you are with the NIC i would say you are compitant enough to change tails (according to NIC that is)


tell them you want to speak to the other spark...my guess is they wont be able to find his number!!!

 

[Notsosmart]

We asked a qualified (37 yrs experience) NICEIC registered electrician to investigate what had gone wrong with our system, and why Di had suffered an electrical shock. He found the fault within a few minutes, as the live and neutral tails coming into the basement consumer unit had been switched by you, at the end of the days work you did for us. You'll recall no doubt that you put the live power back into the old consumer unit after partially installing the new box, but as this was incomplete you put the tails back into the old unit - but critically you put them in the wrong way round. I can easily obtain written confirmation of this by the new registered electrician should you wish me to. He was shocked and appalled by your mistake, and was amazed that you hadn't performed any safety checks that could have quickly detected the problem, and averted the shock.

Feel for you Pmoyne

I would take them up on this offer first, before accusing them of trying to scam you and before you get anyone else involved.
If as others suspect this other electrician is in fact bogus you can easily check his NIC registration (make sure you ask for his NICEIC number to be included in the report)

BTW I once replaced tails to existing Henly blocks only to find that the meter fitter had put in his cables in reverse polarity ( I.e. black out of the meter) if I hadn't noticed & just connected like for like then I could have had the same situation, although polarity checks would have highlighted the issue.

 

[pushrod]

Just trying to get my head round this - not sure but am i right in thinking that rectifiers in appliances would be unaffected by a L - N reverse ? (just thinking about bridge rectifier? diode types.)

And if an earth fault developed (to the neutral) this would still trip an rcd but it would not stop the fault , but then wouldn't the main fuse then blow ?

 

[wattsup]

If poles were reversed, then snooker on telly would be fun...cos the balls would jump out of the bags..is the hoover blowing rather than sucking? is the fridge getting hot?...

 

[pushrod]

If poles were reversed, then snooker on telly would be fun...cos the balls would jump out of the bags..is the hoover blowing rather than sucking? is the fridge getting hot?...

that's what i was wondering about - depends on the type of motors involved though doesn't it? If they are dc motors through a rectified source they won't misbehave? but if they were ac ones they would go backwards or am i thinking about 3 phase with a wire out of place ?? nope it is too late at night for me - i should have paid more attention in the motor lectures - can't get my brain in gear

Mind the whole thing sounds very suspicious - why wouldn't the customer call the original electrician back straight away as soon as they thought something was wrong?

 

[martysparky]

The socket in reverse I found had an iron plugged in it and it didn't freeze the clothes.

Things would still work correctly except they would remain live even when the switch is open and the appliance appears off.

As far as I know not sure about motors either.

Did the washing machine make the clothes dirty. Maybe that was the shock.

 

[shane]

don't know abouut you guys but cheque the polarity before during and after installation of ccu or any circuit installed, the very first thing you do before energising the cu is wait for it"polirity"...

 

[martysparky]

check three times, once for each conductor.

Triple check!