# Reverse Polarity Tester



## Hezbez (Feb 7, 2009)

On the advice of a member on here I bought one of these when I was in Screwfix today;

http://www.screwfix.com/p/ced-plug-in-socket-tester/76975


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## rosalan (Aug 24, 2009)

If only you had gone to the Newbury Show, you may have been able to win one in the raffle :lol: 
Alan


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## Molenoux (Aug 26, 2010)

Had one of these for a long time. They are very good, and worth having. we usually leave ours plugged in so it is seen every time we hook up.

Its surprising how many times it indicates a fault.

Cheers

Molenoux


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## DJMotorhomer (Apr 15, 2010)

Hi

Yes we have one exactly the same but was only £1.99 off Ebay. 

Always better to be safe than sorry


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## Patty123 (Oct 4, 2010)

We have one too, brilliant.


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## rosalan (Aug 24, 2009)

Here is the question.
If the tester shows that the live and neutral are swtched round. What will happen?
Most devices in my van should be able to cope and have done for ages. So what should I do if the socket indicates a problem and why?
Alan


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## bognormike (May 10, 2005)

rosalan said:


> Here is the question.
> If the tester shows that the live and neutral are swtched round. What will happen?
> Most devices in my van should be able to cope and have done for ages. So what should I do if the socket indicates a problem and why?
> Alan


I used to have a blue connector wired the wrong way round to link up when this happened, but gave up bothering :roll: . As long as you don't go touching any live wires (neutral or live in the plug) then you shouldn't get electrocuted :roll: . I think it was unclenorm who said about not sticking a knife in the toaster, but I don't think I'd do that even if it was wired up "correctly" :roll:


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## Zebedee (Oct 3, 2007)

bognormike said:


> I used to have a blue connector wired the wrong way round to link up when this happened, but gave up bothering :roll: . As long as you don't go touching any live wires (neutral or live in the plug) then you shouldn't get electrocuted :roll: . I think it was unclenorm who said about not sticking a knife in the toaster, but I don't think I'd do that even if it was wired up "correctly" :roll:


Me too, except that I never bothered in the first place. :wink:

I took advice from our highly qualified electrician neighbour, also a motorhomer, and he never bothers. Good enough for me.

If you do get an irresistible urge to dismantle the toaster, pull the plug out first and you will be safe . . . assuming you can put it back together again in time for the Memsahib's breakfast toast!! :roll: :lol: :lol: :lol:

Dave


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## clive1821 (Mar 27, 2010)

Yep me too..... These testers are useful to me to do a quick check when doing a new install... It will have no effect which way you have the mains around the earth is import and if you need the RCD to work..... That's about it..... Quite frankly I would not worry to much about it.... If you find something wrong what are you going to do about it anyway..... Yes they are useful but you need to understand what it's saying and be able to fix the problem....


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## Zebedee (Oct 3, 2007)

Hi Clive

I also use mine to check for an earth connection (when I think about it). Wasn't going to mention it since it gives something else to worry about. :roll:

"Reversed polarity" is not far removed from gassing threads. I don't know of *anybody *who has been genuinely gassed, or electrocuted because of R/P! :roll:

I do know of several who have cut themselves badly with a baked beans tin though . . . which makes baked beans statistically more dangerous than reversed polarity on an ac supply!! (_Cue the fart jokes_!! :lol: :lol: )

Reversing the polarity on a dc supply is entirely another matter. 

Dave


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## dipsticks (Aug 2, 2007)

If I was bothered about reverse polarity I would connect a neon indicator from an old appliance across earth and neutral on the supply.

If it lit up the polarity would be reversed.

If it did'nt the polarity would be correct.


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## rosalan (Aug 24, 2009)

I did meet a motorhomer with a compressor type freezer who claimed that the reversed polarity destroyed the motor and on another occasion in France where the whole van became live; that was real, I touched it. Moved power point and all was ok! This spread over 40 years; so not too many issues.
Alan


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## Penquin (Oct 15, 2007)

We have one and have had for years, we have detected "reversed polarity" several times on continental sites and I have a spare short length with reverse wiring simply to swap it back.

Why? :? 

Because at the time we got one it seemed sensible, when we plugged in to reverse polarity it also showed as a warning bulb on our mains input, and we were concerned as the handbook said to be concerned.....  

BUT really it is not needed provided you do not intend to start rewiring appliances that are still plugged in. In the UK our switches cut ONE of the two wires, we are told it is the "live" but of course with AC the polarity is reversed 50 times per second...... 8O 

My understanding of the electrical regs on the continent are that the circuit breakers they use instead of fuses and switches a) cut off much quicker than fuses if there is a fault and b) cut off BOTH wires so the whole system has no chance of causing a problem.  

Of course the "polarity" does not matter for the actual running of an AC appliance as far as I am aware - there are numerous threads on here which say so produced by people with many more active brain cells crammed full of electrical understanding that my limited amount who will come along and point out any errors of understanding that I have stated in this post.... :wink: 

But we will still plug it in and check every time "just in case" and 'cos we have got it and might as will use it........ :lol: :lol: 

Dave


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## Remus (Feb 10, 2011)

>>>>>Here is the question.
If the tester shows that the live and neutral are swtched round. What will happen?
Most devices in my van should be able to cope and have done for ages. So what should I do if the socket indicates a problem and why?
Alan<<<<<

As you say, most devices can cope with reverse polarity so nothing will happen. But, whilst things still turn on and off as normal, they will be live. Normally switches cut the power in the live wire, ie BEFORE it enters the item being powered, if polarity is reversed the switch cuts the power in the neutral wire, ie AFTER it leaves the item being powered. So, for instance, if you were changing a bulb in a reversed polarity situation you would get a shock if you happened to touch the terminals. I'm no electrician and this is only my very simplistic understanding of things. Maybe someone better qualified can expand on this. In the meantime I always check polarity and correct it if reversed, it only takes minutes to swap live and neutral in the mains hook-up cable - or no time at all if you have a prepared 1 metre extension cable with live/neutral already swapped over.


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## Zebedee (Oct 3, 2007)

What you say is correct Remus, but only those wishing to confirm Darwin's Theory of Natural Selection would firtle about inside an appliance without pulling the plug out at the socket. 8O 8O

With just a smidgen of common sense it's easily possible to survive a hookup with "_reversed polarity_" - even though the term is meaningless when dealing with alternating current. :roll:

As you quite rightly say however, if anyone is bothered it's dead easy to make, or cheap to buy a short lead with reversed connections to insert between the hook-up post and their van.

Dave


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## DTPCHEMICALS (Jul 24, 2006)

I have one in a box of unused gadgets somewhere in the garage.
Sargent box in mh has a warning light for reverse polarity.
Dae p


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