Reverse Polarity

[Corrinne]

Just been trying to understand why my motorhome keeps displaying “reverse polarity detected”. Don’t understand electricary and what I read went right over my head. It seemed to be saying that the EHU in Europe is often wired differently from that needed for a British motorhome. Does anyone know whether reverse polarity is dangerous?

 

[LesW]

Quite common in France, makes no difference.

 

[Figaro]

I'm going for popcorn

 

[Odd-no-more]

There is a low risk because on a British van the protection is on the line (live) wire so with reversed polarity that puts the mcb (protection) after the appliance. Continental vans have protection on both line and neutral. But the EHU post will have it's own protection so the risk is not great. I carry an adapter for reverse polarity but a lot of people don't worry at all. Don't let it spoil the trip.

 

[pappajohn]

You won't be dismantling any electrical appliances while they are plugged in or turned on so regardless of what you read. IT IS NOT DANGEROUS.
The French, Germans, Dutch, Spanish, Belgians don't care, is only us British still living in the electrical 20th century that can't cope.

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[Camping Gaza]

I'm going for popcorn

Got mine... ? ? ? Oh no its a bit of steak, bacon and a chicken drumstick. Oh well.

 

[bigtwin]

You won't be dismantling any electrical appliances while they are plugged in or turned on so regardless of what you read. IT IS NOT DANGEROUS.
The French, Germans, Dutch, Spanish, Belgians don't care, is only us British still living in the electrical 20th century that can't cope.

Wot ‘e Z

Ian

 

[Bognor Saint]

It's very easy for those with a knowledge of electrity to be flippant. The OP is obviously worried. Some vans show a warning when reverse polarity is detected and in my case it worried me until I understood the problem.
Yes it's been debated to death on here but it will still be raised occasionally.

 

[Camping Gaza]

In case anyone on here gets snotty about my meal tonight, ( I like raw steak) I have a solution for the OP if they are worried and want to CORRECT the problem. You can get an adapter for your EHU lead:

Link: http://rover.ebay.com/rover/1/710-5...0001&campid=5338547443&icep_item=251508486659

 

[Bobd]

I was once trying to explain reverse polarity to a very nice Irish guy in northern Spain. He then quipped " so that's what they mean by alternating current"

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[Corrinne]

Thank you very much for your answers. My partner is in hospital in Spain at the moment so I’m worrying about things I would normally get him to look at.

 

[Camping Gaza]

Hope he gets better soon

 

[Drifter]

In case anyone on here gets snotty about my meal tonight, ( I like raw steak) I have a solution for the OP if they are worried and want to CORRECT the problem. You can get an adapter for your EHU lead:

Link: http://rover.ebay.com/rover/1/710-5...0001&campid=5338547443&icep_item=251508486659



View attachment 320538

Can I use this on my amazon account? I,ll be rich ?

 

[thebriars]

In case anyone on here gets snotty about my meal tonight, ( I like raw steak) I have a solution for the OP if they are worried and want to CORRECT the problem. You can get an adapter for your EHU lead:

Link: http://rover.ebay.com/rover/1/710-5...0001&campid=5338547443&icep_item=251508486659



View attachment 320538

Anyone who understands so little about electricity to think that reverse polarity is an issue in a modern van ought not to be making themselves one of these!

As for buying one, its illegal to sell them in the UK. Don't trust things like this you see on Ebay to be safe!

 

[thebriars]

There is a low risk because on a British van the protection is on the line (live) wire so with reversed polarity that puts the mcb (protection) after the appliance. Continental vans have protection on both line and neutral. But the EHU post will have it's own protection so the risk is not great. I carry an adapter for reverse polarity but a lot of people don't worry at all. Don't let it spoil the trip.

Don't assume this is always true. The last 2 different make British heaps of junk caravans I had both had double pole MCBs. In any case it still doesn't matter in the slightest, as pappajohn said.

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[Guigsy]

If your van has switches on the 3-pin 240v sockets, a reversed polarity connection could mean that even if the switch is off, there's still a live connection.

But most vans don't have switches on their 240v sockets (for this reason), so to turn the appliance off you have to pull the plug out which means there's no chance of an unsafe connection. Simples.

 

[Camping Gaza]

? mmmm butterkist

 

[autorouter]

Anyone who understands so little about electricity to think that reverse polarity is an issue in a modern van ought not to be making themselves one of these!

How do you know it's a modern van? How do you know it will be plugged into a modern electricity supply? Does the fact that there's a 'reverse polarity indicator' not raise the possibility that the system is not a modern one?

If there is no RCD in the system, then even though it is safe when working properly, it is dangerous in many fault scenarios

 

[sallylillian]

Thats good all the appliances and plugs I have with L1 and N on I can ignore and wire them how I fancy. Stuffing a live circuit up the un-switched side of an electric kettle is of no consequence, I never realised that.

 

[Clive and Kerri]

Thats good all the appliances and plugs I have with L1 and N on I can ignore and wire them how I fancy. Stuffing a live circuit up the un-switched side of an electric kettle is of no consequence, I never realised that.

If the kettle is made for sale in the EU, then no as it will be designed to cope with this.

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[sallylillian]

If the kettle is made for sale in the EU, then no as it will be designed to cope with this.

Just to be clear, it will have a double pole switch?

 

[sallylillian]

And supplementary, I can ignore L1 and N as they are irrelevant?

 

[Clive and Kerri]

And supplementary, I can ignore L1 and N as they are irrelevant?

I wouldn’t in the UK, not that you get a choice as all electrical appliance have to sold plug on. In answer to your other question yes anything manufactured to be sold in the EU will have a duel pole switch because they have higher standards than us.
I still alway check any EHU I go on to make sure it has an Earth. Now that is important.

 

[Camping Gaza]

I'm on my second carton of popcorn and want this to last so........

AC is AC, When an appliance (as I understand it) has no earth, ie something that is encased in plastic, or has the Square withing a Square symbol meaning its DOUBLE INSULATED the live and neutral doesn't really matter, if you check the power cord, often there is no earth wire.

such as figure 8 cables found on a lot appliances, shavers, some electronics like TVs or DVD players etc, so you can plug these in any which way you like.

When there is an EARTH cable attached to that appliance, and in UK ring main circuits, you should observe the correct "polarity" (but there actually is no polarity in Alternating current really as the polarity swings 50 times a second in the UK and europe (30x in the USA and some other countries)

So live and neutral actually MEAN something. It's to do with EARTH BONDING as it's know in the trade.

So.... Earth bonding....

Neutral is a circuit conductor that normally carries current back to the source. Neutral is usually connected to ground (earth) at the step-down transformer of the supply. (substation)

This is to do with safety, that's why in the UK wall sockets (most of them) have switches so when switched off the appliance is STILL CONNECTED to the Earth bond at the substation (for safety) but the live is disconnected (open circuit) This is NOT the case in europe, most wall sockets are not switched, especially France as there are no ring mains.

This is in case the house or campervan IS NOT CONNECTED TO A LOCAL EARTH or the earth has failed (as I understand it)

SO.... if your Live and Neutral connections are reversed, its not a good idea really because there is a slim chance your appliance's casing (like a metal cased electric toaster or kettle) could still be live

I think this is more likely in case of a camper on hookup, because you dont know if the hookup point even has an earth.

So here is where it gets interesting and I have no knowledge of this....

What about if you plug a generator into your hook up.???? how many of you stick an earth spike into the ground??? do you need to???

You are curing your hair inside your camper ladies with reversed polarity, bare feet, still holding the tongs (now cool put plugged in switched off) that have a live outer casing and step outside on to the wet grass?

I am no expert in power distribution, so if any of this is wrong my apologies, it's how I understand it, and I am always open for further education.

opens another carton of butterkist.

 

[thebriars]

How do you know it's a modern van? How do you know it will be plugged into a modern electricity supply? Does the fact that there's a 'reverse polarity indicator' not raise the possibility that the system is not a modern one?

If there is no RCD in the system, then even though it is safe when working properly, it is dangerous in many fault scenarios

I don't know if its a modern van, but my comment explicitly related to a modern van if you read back.

Frankly, just as in domestic wiring, anyone using a motorhome without an RCD is putting themselves at a significant risk anyway. No system without an RCD can be considered safe today.

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[thebriars]

What about if you plug a generator into your hook up.???? how many of you stick an earth spike into the ground??? do you need to???

This is an interesting one. Normally the neutral of a genny (or portable inverter) is not connected to earth, and my following comments assume this. Check your own genny if unsure.

Basically if you don't earth a genny, the RCD will still work as it does not use the earth.

However, if you do decide to bond the earth and neutral and use an earth rod, it will need to be 1m long to be effective. Not that easy in stony ground. Even so, how can you be sure it is effective as soil conditions can vary enormously. There is no easy way to test it. Then you've got to get it out again!

If you don't link neutral and earth on a genny, then you have to touch both live and neutral together to get a shock. Touch live and earth and you should not get a shock, though this all depends on the quality of the genny and its insulation characteristics. This situation is similar to being double insulated.

However if you do link neutral and earth, then you only need to touch the live, and any bonded metal part to get a shock.

 

[tonyidle]

be 1m long to be effective

...... and some. A one metre earth spike in any ground, unless watered daily, is unlikely to be a decent earth.

 

[tonyidle]

SO.... if your Live and Neutral connections are reversed, its not a good idea really because there is a slim chance your appliance's casing (like a metal cased electric toaster or kettle) could still be live

If you don't link neutral and earth on a genny, then you have to touch both live and neutral together to get a shock. Touch live and earth and you should not get a shock, though this all depends on the quality of the genny and its insulation characteristics. This situation is similar to being double insulated.

However if you do link neutral and earth, then you only need to touch the live, and any bonded metal part to get a shock.

The RCD in the van protects by looking for a current imbalance between L & N. If there is an imbalance because someone or something connects the L to earth, thus reducing the current flowing in the Neutral, then the RCD will trip. For there to be danger a person has to be in contact with L and earth or a representation of it (faulty genny casing perhaps). The RCD will trip. Any connection that results in the N being bypassed, including all the cases mentioned, will trip the RCD. So there is a danger, assuming either a faulty appliance or miss-operation of same, of receiving a shock - but only the safe minimum shock that results in tripping the RCD.

 

[Puddleduck]

Thank you very much for your answers. My partner is in hospital in Spain at the moment so I’m worrying about things I would normally get him to look at.

I hope your partner is okay and back with you very soon.

If you need any information please ask and ignore the people who go off on a tangent and argue about stuff you don't need (or want) to know about right now.

Is there anyone in Spain near where this Funster is right now who could give some help / support ?

 

[thebriars]

The RCD in the van protects by looking for a current imbalance between L & N. If there is an imbalance because someone or something connects the L to earth, thus reducing the current flowing in the Neutral, then the RCD will trip. For there to be danger a person has to be in contact with L and earth or a representation of it (faulty genny casing perhaps). The RCD will trip. Any connection that results in the N being bypassed, including all the cases mentioned, will trip the RCD. So there is a danger, assuming either a faulty appliance or miss-operation of same, of receiving a shock - but only the safe minimum shock that results in tripping the RCD.

Just one snag with your post. Your first sentence is quite correct, however, don't get hung up on the idea of an earth, because running off an un-earthed genny is not the same as the mains. You need to consider the circuit path. If there is no connection to earth anywhere within the genny or the electrical system then touching L and earth will not make a circuit and therefore will not give someone a shock. You cannot have a "representation" of earth, either you have a circuit or you don't. Its no different to standing on a well insulated mat in dry conditions and touching the live.