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.