reverse polarity (1 Viewer)

[tilly ivimey]

Hello, we are off to France in September in our new second hand VW camper. I,ve been told I need to check for reverse polarity when I hook up, can someone explain this to me, or point me in the right direction to find out? Many thanks in advance, Bill and Tilly

 

[johnsandywhite]

oh: This is another one of those arguments that never gets sorted.

I say 'IT MAKES NO DIIFERENCE'. WHY?

The Microwave will not work the wrong way round.
The Fridge/Freezer will NOT heat up instead of cooling down.
The lights will NOT turn off when you turn them on. etc, etc, etc, etc in ad finitum.

The ONLY difference is IF there is a problem with the wiring. ie: An Earth is connected in some way with the live or neutral and they get connected somehow.
But THEN there will only be a problem if the Chassis is grounded and you touch the chassis or anything connected to the chassis.
Also there is the possibility that IF the chassis is LIVE and it is RAINING? You MAY get a tingling sensation when you touch the bodywork. :thumb:

 

[Kon tiki]

You can get a plug with 3 LED's for checking the polarity heres one Link Removed but they are readily available at most caravan dealers. They also show that the earth is working correctly.
From what I understand the only problem is for UK designed motorhomes where we only have a fuse or trip switches on the live wire. On most continental vans they have trip switches which isolate both live & neutral wires so it isn't really an issue for them.
The danger is in the event of blowing a fuse or a relay tripping & the polarity is reversed then the neutral wire is still live. You can either make a short fly lead with the wires crossed over if you find the polarity wrong.

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[stagman]

Hello, we are off to France in September in our new second hand VW camper. I,ve been told I need to check for reverse polarity when I hook up, can someone explain this to me, or point me in the right direction to find out? Many thanks in advance, Bill and Tilly

It will make a difference . You will be switching the neutral instead of the live for a start .If a fuse blows the appliance will still be live . If an mcb trips the appliance will still be live .Please don't listen to people who say it won't make a difference buy a cross over lead it will only cost you a couple of quid and it could save your life :Angry:

 

[scotjimland]

The Microwave will not work the wrong way round.
The Fridge/Freezer will NOT heat up instead of cooling down.
The lights will NOT turn off when you turn them on. etc, etc, etc, etc in ad finitum.

you forgot to mention that fans won't suck instead of blowing

I agree with John, however, if you are concerned, buy a plug in polarity tester and a reverse polarity connector cable from any decent caravan supplies shop.

When you hook up, plug in the tester, if it shows reverse then use the reverse polarity connector cable.

jim

 

[Peter JohnsCross MH]

There is a tester available cost £10-75 or an installed 'tester and changeover switch' at £39-99p.

Peter

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[stagman]

There is a tester available cost £10-75 or an installed 'tester and changeover switch' at £39-99p.

Peter

Well worth it as far as I am concerned :thumb:

 

[sinbad1]

Ask yourself


Would an electrician give a safety certificate for your 240v system if it was wired with polarity reversed?

I doubt it, and IMO with electric or gas its not worth taking any risk . Best thing to do is seek advice from those that are qualified.

Regards

 

[ips]

It will make a difference . You will be switching the neutral instead of the live for a start .If a fuse blows the appliance will still be live . If an mcb trips the appliance will still be live .Please don't listen to people who say it won't make a difference buy a cross over lead it will only cost you a couple of quid and it could save your life :Angry:

I totally agree, I have had at least two elecy shocks whilst working on equipment with reversed polarity when the isolator has been switched off. (Yes I know you shouldnt rely on the isolator neon and test it with a metre so yes its was my fault) Maybe it isnt a problem with your equipment working correctly but in the event of a fault as outlined by Mr stagman your neautral is still live regardless of your cb/mcb etc saying otherwise ???

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[The Wallace]

your neautral is still live regardless of your cb/mcb etc saying otherwise ???

You are working in a van - all you need to do is pull the plug from the hookup if you want to work on the inside of any appliance - but how often do you need/want to work on the inards of an appliance when camping.

My reverse lead is somewhere in my shed and will go in the bin when I find it - I have never found a reversed live/neutral (it's NOT bloody polarity!!) in weeks of camping on sites in France.

If it makes you happy get a reversing lead but don't try the nanny state type scaremonger tactics on everyone else.

 

[Snowbird]

Hi all,mabe someone can explain why my polarity tester works fine on hookup,but when genny is running all sorts of strange things happen to it,somtimes it tells me no earth,somtimes pos and neg reversed.

 

[twooks]

can't help Snowbird, or anyone else with tecchie questions,
but we frequently come across it, can't understand how some people can claim never to have encountered it in all their years touring - we often get different response from different connections on same branchement

simply wire up a length of lead to cope with reversal o live / neutral, if nothing else it stops the little red warning light getting on my nerves.


but - more importantly, come on England

:thumb::thumb::thumb:

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[pappajohn]

Hi all,mabe someone can explain why my polarity tester works fine on hookup,but when genny is running all sorts of strange things happen to it,somtimes it tells me no earth,somtimes pos and neg reversed.

possibly not a smooth enough supply.

is it an invertor genny (kipor/honda) or a straightforward 230v AC (builders/B+Q/Aldi genny)

 

[Wildman]

Hi all,mabe someone can explain why my polarity tester works fine on hookup,but when genny is running all sorts of strange things happen to it,somtimes it tells me no earth,somtimes pos and neg reversed.

for a tester to show the polarity (with respect to earth) an earth must be connected, if your Genny is not connected to an earth spike you will see variable readings. If it is mounted in the van it must be bonded correctly to earth (the chassis).

 

[Snowbird]

possibly not a smooth enough supply.

is it an invertor genny (kipor/honda) or a straightforward 230v AC (builders/B+Q/Aldi genny)

Hi John,Its the built in Onan,You had the pleasure of listening to it at Malvern Remember the security visit

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[Wildman]

You are working in a van - all you need to do is pull the plug from the hookup if you want to work on the inside of any appliance - but how often do you need/want to work on the inards of an appliance when camping.

My reverse lead is somewhere in my shed and will go in the bin when I find it - I have never found a reversed live/neutral (it's NOT bloody polarity!!) in weeks of camping on sites in France.

If it makes you happy get a reversing lead but don't try the nanny state type scaremonger tactics on everyone else.

you are missing the point. pos and neg are the same yes but one side is connected to earth so should you be quoting with respect to earth. now in the event of a fault the fuse is in the wrong line and your chassis/all metalwork in the van will become live. Thereby able to deliver you a shock under fault conditions only. Some electronics are very dependant on polarity with respect to earth so also needs protecting. A/C current is exactly that alternating current current flow in the cable is constantly changing direction. What makes one live and one nuetral is the fact that one side it tied to earth, the other side is fused. Hope that explains it. (City and guilds 224 and HNC (M.elec)

 

[Losos]

Hello, we are off to France in September in our new second hand VW camper. I,ve been told I need to check for reverse polarity when I hook up, can someone explain this to me, or point me in the right direction to find out? Many thanks in advance, Bill and Tilly

The truth is out there in the above posts, but there is a lot of smoke and mirrors too

Basically, in some parts of Europe it is standard to wire the Live and Neutral of the wall socket opposite to what is the standard in UK, that is why you may sometimes need a Live / Neutral reverse lead.

How do you know ? get one of those £10 testers, worth every penny.

The smoke and mirrors ? Well that's when talk of the earth wire surfaces, yes occassionaly there may be an earth fault but even in the 'backward' parts of Europe the 'leccies usually get that wire in the right place and once again the £10 tester will tell you and that's when you tell the site owner or move somewhere else

Is talk of 'polarity' correct, well that is a subject that could be discussed for weeks on end. Polarity on DC circuits is understood, on AC it's not 'quite' the correct terminolgy, but many people couldn't care less (I do care but that's hardly relevant is it)

 

[Losos]

you are missing the point. pos and neg are the same yes but one side is connected to earth so should you be quoting with respect to earth. now in the event of a fault the fuse is in the wrong line and your chassis/all metalwork in the van will become live. Thereby able to deliver you a shock under fault conditions only. Some electronics are very dependant on polarity with respect to earth so also needs protecting. A/C current is exactly that alternating current current flow in the cable is constantly changing direction. What makes one live and one nuetral is the fact that one side it tied to earth, the other side is fused. Hope that explains it. (City and guilds 224 and HNC (M.elec)

Good point Roger, yes it is important to get it right, I forgot to mention above that you can get a shock from having the two wires reversed.

What I don't like to see is talk about the earth wire being wrongly wired as in my experience that is quite rare (OK the neutral is taken to earth at the supply point but not usually anywhere else, or is it done at the consumer unit?)

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[stagman]

you are working in a van - all you need to do is pull the plug from the hookup if you want to work on the inside of any appliance - but how often do you need/want to work on the inards of an appliance when camping.

My reverse lead is somewhere in my shed and will go in the bin when i find it - i have never found a reversed live/neutral (it's not bloody polarity!!) in weeks of camping on sites in france.

If it makes you happy get a reversing lead but don't try the nanny state type scaremonger tactics on everyone else.

sad

 

[The Wallace]

sad

Wow that's informative.

you are missing the point. pos and neg are the same yes but one side is connected to earth so should you be quoting with respect to earth

IS this situation not unique to the UK where it is a left over from our early DC supply?

Since our van has Shuko outlets then live / neutral has no meaning since the plugs can be inserted any way up. Therefore it is scaremongering to tell everyone to use so called 'polarity' changers.

Alan, HNC & BSc.

 

[simsy56]

l agree with the Wallace, this rubbish should be in the bin with the gas stories!

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[Wildman]

Wow that's informative.
IS this situation not unique to the UK where it is a left over from our early DC supply?

Since our van has Shuko outlets then live / neutral has no meaning since the plugs can be inserted any way up. Therefore it is scaremongering to tell everyone to use so called 'polarity' changers.

Alan, HNC & BSc.

All systems tie one side to earth, providing you have fuses in BOTH lines what you say is correct, otherwise my observations are valid. My qualifications are in Elecronic and Electrical engineering, what I wonder are yours. As you seem to be consistantly missing the point. What you choose to do is your choice but don't bamboozle uninformed persons with the BBB principle.
Roger G&G, HNC, LE

 

[stagman]

Wow that's informative.
Yes as informative as the load of drivle you have just posted . If you don't know what you are talking about and obviously with no electrical knowledge please don't ill advise others especially when it comes to their safety .

 

[vwalan]

hi, the wallace is talking about schuko plugs as used on the continent the live /neutral can be on either pin and the plugs fit both ways. the earth can be top bottom as well . i,m only trying to be the devils advocade(or what ever).in europe if you use the continental plug you just stick it in . cant give tec advise but have used schuko plugs alot.

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[The Wallace]

There are no safety implications if you just unplug the hookup before tampering with appliances.
How many people have been harmed in caravans or motorhomes because of reversed live / neutral connections? About the same number as have been proved to have been gassed.

How do you explain the safe, widespread use of Shuko, reversible, conectors in European vans (and dwellings)?

 

[scotjimland]

ll systems tie one side to earth, providing you have fuses in BOTH lines what you say is correct, otherwise my observations are valid.

Sorry Roger but I disagree, or maybe I misunderstand your post .. but the neutral is not tied to earth on the consumer side .. if it were the RCD would trip..

I'm not giving an electrical lecture or telling anyone how to suck eggs , or indeed whether to be concerned about reverse polarity or not.. but this thread has gone the way of all others on this topic..

It is important to test for a good earth and using a reverse polarity tester will do that, if for that reason and no other then it's worth doing .... however ..

A modern motorhome and it is equipped with an earth leakage current detecting main circuit breaker. (RCD) These breakers do this by accurately comparing the current flowing in the NEUTRAL wire with that flowing in the LIVE wire. If these currents are not almost identical (because some has flowed elsewhere - like via earth back to the transformer) then the trip will operate disconnecting both LIVE and NEUTRAL connections.

If you have an appliance with an earth leakage fault and the Mains hookup is connected correctly then the earth leakage trip will operate when you switch on that appliances ON/OFF switch.

If the mains hookup is connected with reverse polarity and you have an appliance with an earth leakage fault then the trip will operate as soon as you connect your hookup irrespective of the appliances ON/OFF switch (unless its double pole switching).

If you have an OVERLOAD situation then the circuit breaker supplying the circuit which has the overload will open irrespective of supply polarity. If this overload is because of an earth fault then the earth leakage trip will operate anyway.

So, I would not worry about reverse polarity unduly as faults will get picked up one way or another. Quite possibly sooner if the polarity is reversed !

In all my years of camping with both caravans and motorhomes I have never tested for polarity .. Why ? because I see no valid reason to do so.. as previously stated, the only risk of reverse polarity is if someone switches off an appliance, then opens it up to repair it without unplugging. They don't need a tester, they need their head examined .


Jim.. school of life HNC PHD..

 

[stagman]

Sorry Roger but I disagree, or maybe I misunderstand your post .. but the neutral is not tied to earth on the consumer side .. if it were the RCD would trip..

First of all overload and earth leakage are two completelly different situations . And RCD is there to protect earth leakage . If you do not have a good earth it is likely the trip won't work , that is one good reason to use your plug tester . An MCB is a modern fuse ,it is there to protect short circuit and overload . One situation , if you had a metal clad appliance i.e. kettle ,toaster and combined with reverse polarity, short circuit and earth fault and no earth then the metal casing of that appliance could become live and fatal .
And Roger is not wrong .On a PME system the earth shares the neutral supplied by your electricity company . Why Jim can't you encourage the safety of newbies on this site . You have been M/Homing for a long time and may be one of the lucky ones.For the cost of £15 for a plug tester and reverse lead it could save someones life .On most new vans a reverse warning alarm is fitted so that must say something in itself .

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[scotjimland]

And Roger is not wrong .On a PME system the earth shares the neutral supplied by your electricity company .

I am well aware how the PME system works ... what I said
the neutral is not tied to earth on the consumer side .. if it were the RCD would trip..


Why Jim can't you encourage the safety of newbies on this site . You have been M/Homing for a long time and may be one of the lucky ones.For the cost of £15 for a plug tester and reverse lead it could save someones life .On most new vans a reverse warning alarm is fitted so that must say something in itself .

I have already said..

if you are concerned, buy a plug in polarity tester and a reverse polarity connector cable from any decent caravan supplies shop.

When you hook up, plug in the tester, if it shows reverse then use the reverse polarity connector cable.

After connecting to the EHU it is important to test the RCD using the test button .. and I already acknowledged that the reverse polarity tester was useful to check for a good earth..

It is important to test for a good earth and using a reverse polarity tester will do that, if for that reason and no other then it's worth doing ..

nothing more to add, and as I said before these arguments go on and on and on..

No one has yet given a scenario (apart from opening up an appliance still pugged in) , where reverse polarity alone can lead to electrocution...

Please tell me under what circumstances it is dangerous and I'll be the first to jump up and down and encourage everyone to get one asap... including myself..


jim

 

[The Wallace]

One situation , if you had a metal clad appliance i.e. kettle ,toaster and combined with reverse polarity, short circuit and earth fault and no earth then the metal casing of that appliance could become live and fatal .

This thread is getting too silly!!
In the above scenario, reverse 'polarity' has nothing to do with the the appliance becoming live and fatal.

Please remember that th IEEE Regulations were instituted to protect Consumers from the electrical contracting industry, not to protect electricians from consumers.

Time to go to work, enjoy!

 

[stagman]

This thread is getting too silly!!
In the above scenario, reverse 'polarity' has nothing to do with the the appliance becoming live and fatal.

Please remember that th IEEE Regulations were instituted to protect Consumers from the electrical contracting industry, not to protect electricians from consumers.

Time to go to work, enjoy!

Yes it is silly and saddening when people don't listen

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