help plug the mains lead into van at home everything works but the fuse box as lit up saying reversed polarity no fuses gone does someone have any ideas please
reversed polarity
- Thread starter bryan_5039989
- Start date
I can only assume that this is a serious question.
Whoever wired up the mais lead must have wired it for France.
Undo the plug & socket and make sure that the brown / red cable goes to the possitive pins and the black / blue cable goes to the negative pins
Whoever wired up the mais lead must have wired it for France.
Undo the plug & socket and make sure that the brown / red cable goes to the possitive pins and the black / blue cable goes to the negative pins
- Mar 14, 2005
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Hello Bryan,
There is no need to panic!
What reverse polarity means is that at some point between the supply source and your caravan fuse box the Live and Neutral wires have been crossed connected somewhere.
Does the same happen with every hook up point you use in the UK, or just one? If it only happens with one point, it suggests the hook up point may be wired incorrectly, and that should be put right.
If the converse is true and it happens with all or most points, it suggests that your hook up cable may be wired incorrectly. Check both ends of the Electric Hook Up lead, The designations of each of terminals in the blue plugs and sockets should be marked, so checking should be easy.
As ever if you don't feel confident with mains wiring then refer the job to a qualified electrician.
There is no need to panic!
What reverse polarity means is that at some point between the supply source and your caravan fuse box the Live and Neutral wires have been crossed connected somewhere.
Does the same happen with every hook up point you use in the UK, or just one? If it only happens with one point, it suggests the hook up point may be wired incorrectly, and that should be put right.
If the converse is true and it happens with all or most points, it suggests that your hook up cable may be wired incorrectly. Check both ends of the Electric Hook Up lead, The designations of each of terminals in the blue plugs and sockets should be marked, so checking should be easy.
As ever if you don't feel confident with mains wiring then refer the job to a qualified electrician.
Hi Bryan, Screw Fix have this great piece of kit for testing mains, correct polarity and ensures you have an earth connection, only
John L
No need to panic?......surely if the polarity is reversed then this will inactivate the RCD
My apologies in advance if I am mistaken
best regards, Martin
No need to panic?......surely if the polarity is reversed then this will inactivate the RCD
My apologies in advance if I am mistaken
best regards, Martin
IMO the first thing to check is you house's outlet; is that socket reversed or even are out sockets reversed?
No there's no need to panic. What you have is Live / Neutral reversal. Reverse polarity only exists in DC systems and is a very quick way of blowing appliances.
Mains electricity is AC, which basically means that the "polarity" swaps 50 times per second. With continental 2 pin systems, the live and neutral wires are connected at random and the appliance is plugged in at random. The appliance works fine.
So why worry? If you always unplug an appliance before mucking about with it, you have nothing to worry about. If your live neutral wires are reversed and your sockets are single pole switched and you muck about with you appliances while they are still plugged in, you stand a very good chance of getting electrocuted.
In short, you can only guarantee that an appliance is safe when it is unplugged
Mains electricity is AC, which basically means that the "polarity" swaps 50 times per second. With continental 2 pin systems, the live and neutral wires are connected at random and the appliance is plugged in at random. The appliance works fine.
So why worry? If you always unplug an appliance before mucking about with it, you have nothing to worry about. If your live neutral wires are reversed and your sockets are single pole switched and you muck about with you appliances while they are still plugged in, you stand a very good chance of getting electrocuted.
In short, you can only guarantee that an appliance is safe when it is unplugged
Don't want to worry anyone but reverse polarity can be a very serious situation. You may only have a problem with your hook up lead. It could be your socket at home is wired incorrectly, or it could be your incoming mains supply is reversed. And you CAN have reversed polarity with your ac supply. This is where your supplier or an electrician has made a mistake at the cutout or consumer unit. If this is the case it means your neutral is live and your live is neutral. What does that mean, well your mains fuse sits in what would normally be live if reversed it does not protect the installation with potentially serious consequences should you have an earth fault on an appliance and not be found until someone receives an electic shock. This could be very serious if you have an outside tap connected to the house earth and is touched by someone outside of what is the releative safety of the "faraday's cage" of the house and equipotential bonding. Long and short of it if you cant prove its the lead get the house checked by electrician or supplier.
Happy-Lappy, the RCD will still work if the AC polarity is swapped over, It is only looking at a difference in current (30mA) between Live and Neutral.
Get a CED Plug In Socket Tester from Screw Fix and make sure on every site you go on is correct.
Get a CED Plug In Socket Tester from Screw Fix and make sure on every site you go on is correct.
RCD, trust your luck do you. Working in the idustry have seen many issues. The typical RCD in house is a 100ma trip. And usually a 30ma for external feed such as a garage. If conditions are unfavourable it can take as little as 30ma to kill a fit healthy adult over a very brief time. RCD's must operate within 500 milliseconds if working correctly thats half a second, more than enough to upset the regular heart beat. Over the years have found many operating well outside the time scale and rating. Their good at, damage clearing faults quickly stopping fires etc. but do not prevent electric shock, same advice as before, get in checked. I have seen the results.
RCD's must trip within 40mS, usually trip far quicker than this maybe as quick as 8ms to 10mSecs.
Chris,
I do have a plug in socket tester, but I only ever use it when I hook up abroad. Maybe I should leave it in the van and always check when conecting to the site bollard.
best regards, Martin
I do have a plug in socket tester, but I only ever use it when I hook up abroad. Maybe I should leave it in the van and always check when conecting to the site bollard.
best regards, Martin
I leave my plugin tester permanently plugged in. That way I always know whether my live / neutral are the right way round adn whether I have a working earth. It's the latter that concerns me most. A hookup cable trailing from van to bollard could easily get damaged and I could end up with no wroking earth. If that happens, I want to know about it ASAP
Hmm,this has made me think... I'm going to have to check how my van's sockets are wired. I suppose it's possible, cos there are only a couple of sockets, that it's a continental style radial circuit instead of UK style ring main. If so, the circuit would be protected by a relatively weak fuse and the live neutral issue may not be such a biggie.
I agree with Ian though that if the live / neutral is reversed in the house as opposed to the hookup cable, tehn you have potentially a very dangerous situation which must be checked and rectified by a qualified eletrcian.
I agree with Ian though that if the live / neutral is reversed in the house as opposed to the hookup cable, tehn you have potentially a very dangerous situation which must be checked and rectified by a qualified eletrcian.
- Mar 14, 2005
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I thought I had already added a futher response to this thread, seems I was mistaken.
I originally said 'don't panic', and I stand by that, I also a said if fault exists it does need to be investigated and put right.
Provided all the appliances are working correctly, phase reversal is not a danger, BUT if an appliance goes faulty and you have phase reversal then there is potential danger.
In the UK the wiring regulations are quite strictly adhered to and a professional electrician will test every installation they do to confirm that the live and neutral conductors are properly matched throughout. With such a high level of phase integrity it is reasonable to only switch the live circuit, and this will effectively isolate the supply current. Similarly the over current protection (OCP)= (fuses or MCB's) are in the Live (phase) side of the circuits. In the event that the OCP operates, the live side is disconnected, thus protecting the appliance circuit or operator.
Under UK conditions, this single sided isolation affords adequate protection, BUT if the supply phase has been reversed then even if an appliance has been turned off or the OCP has operated, the neutral conductors will still be at the live potential and thus still represent a hazard.
In many parts of the continent the same strict adherence to phase relationships is not observed. This is known and as a result products destined for the wider continent have to use Double pole switching to ensure that both the 'Live and neutral' circuits are disconnected simultaneously.
Phase reversal in a caravan should not be hazard, but in the interests of consistency and the UK wiring regulations the issue should be investigated and corrected.
I originally said 'don't panic', and I stand by that, I also a said if fault exists it does need to be investigated and put right.
Provided all the appliances are working correctly, phase reversal is not a danger, BUT if an appliance goes faulty and you have phase reversal then there is potential danger.
In the UK the wiring regulations are quite strictly adhered to and a professional electrician will test every installation they do to confirm that the live and neutral conductors are properly matched throughout. With such a high level of phase integrity it is reasonable to only switch the live circuit, and this will effectively isolate the supply current. Similarly the over current protection (OCP)= (fuses or MCB's) are in the Live (phase) side of the circuits. In the event that the OCP operates, the live side is disconnected, thus protecting the appliance circuit or operator.
Under UK conditions, this single sided isolation affords adequate protection, BUT if the supply phase has been reversed then even if an appliance has been turned off or the OCP has operated, the neutral conductors will still be at the live potential and thus still represent a hazard.
In many parts of the continent the same strict adherence to phase relationships is not observed. This is known and as a result products destined for the wider continent have to use Double pole switching to ensure that both the 'Live and neutral' circuits are disconnected simultaneously.
Phase reversal in a caravan should not be hazard, but in the interests of consistency and the UK wiring regulations the issue should be investigated and corrected.
Just to continue this topic, if you travel in France, The householder, caravan park owner is resposible for the earth connection and making sure it is sound. That is, his/her earth rod termination and continuity. The earth cable is not taken back to the supply authority.
Therefore for safety it is essention that British vans are connected to their system correctly.
Therefore for safety it is essention that British vans are connected to their system correctly.
As there are electrically competent contributors here can you please enlighten me on the following Reversed polarity issue:
At a site in France last year I had an indicated "reverse polarity" both using the lead with and without the change over link. As I later confirmed with my multi meter both live and neutral were standing above the earth; as I recall 150 and 70 volts Ac respectively.
The site owner was pretty disinterested, and indeed as he pointed out everything in the van did work fine.
What should I do if I meet this situation again; move on as before?
Thanks John
At a site in France last year I had an indicated "reverse polarity" both using the lead with and without the change over link. As I later confirmed with my multi meter both live and neutral were standing above the earth; as I recall 150 and 70 volts Ac respectively.
The site owner was pretty disinterested, and indeed as he pointed out everything in the van did work fine.
What should I do if I meet this situation again; move on as before?
Thanks John
Graham,
Its sometimes quite difficult to identify a problem without being there and using various devices.
It could be that the site had a very high earth loop impedance (the resistance of a circuit under fault conditions in simple terms) and some one on the site had an earth or neutral fault. With high ELI a circuit breaker would not trip and simply see the fault as load.It could also be a system with poor earthing ( a reference point) and an imbalance in loading across a three phase system. This would have the effect of a voltage in the neutral when referenced to earth and may falsify any polarity reading, depending on test meter used.
Its sometimes quite difficult to identify a problem without being there and using various devices.
It could be that the site had a very high earth loop impedance (the resistance of a circuit under fault conditions in simple terms) and some one on the site had an earth or neutral fault. With high ELI a circuit breaker would not trip and simply see the fault as load.It could also be a system with poor earthing ( a reference point) and an imbalance in loading across a three phase system. This would have the effect of a voltage in the neutral when referenced to earth and may falsify any polarity reading, depending on test meter used.
Thanks Ian,
My own limited experience lead me to think it was an imbalance on the phases.
However the point of asking was firstly to flag up that this oddity can occur when using the simple neon "reverse polarity" detectors but mainly to understand its safety implication should others encounter it?
Cheers John
My own limited experience lead me to think it was an imbalance on the phases.
However the point of asking was firstly to flag up that this oddity can occur when using the simple neon "reverse polarity" detectors but mainly to understand its safety implication should others encounter it?
Cheers John
John,
I'm wary of alot of instruments you can pick up for the DIYer particularly cheaper models. The price inveriably is a reflection of quality and technology. Some of the screwdriver / pen type neon indicators i've come across will light up if tapped or rubbed up and down your arm. Stick to industry recognised names.
Although its good to check conditions on a site I think its equally important to understand the situation thats indicated and the implications. The situation you described I'm sure indicated a poor earth and poorly balanced loads. The implication in this case can seem a little complicated. For electricity to flow there has to be a potential difference and as your van was working correctly there was most probably a potential difference of 230 volts between the neutral and phase despite the readings you had for each. The problem lies in the RCD protection. Simply they measure current flow in the circuit. They compare whats in the neutral with whats in the live but can only do this if they have a point of reference i.e. and earth. So if the site earth is poor there could safety issues.
I'm wary of alot of instruments you can pick up for the DIYer particularly cheaper models. The price inveriably is a reflection of quality and technology. Some of the screwdriver / pen type neon indicators i've come across will light up if tapped or rubbed up and down your arm. Stick to industry recognised names.
Although its good to check conditions on a site I think its equally important to understand the situation thats indicated and the implications. The situation you described I'm sure indicated a poor earth and poorly balanced loads. The implication in this case can seem a little complicated. For electricity to flow there has to be a potential difference and as your van was working correctly there was most probably a potential difference of 230 volts between the neutral and phase despite the readings you had for each. The problem lies in the RCD protection. Simply they measure current flow in the circuit. They compare whats in the neutral with whats in the live but can only do this if they have a point of reference i.e. and earth. So if the site earth is poor there could safety issues.
As I said the owner is resposible fot the earth connection, sounds to me he should go out with a watering can and water his earth rods.
By the way if you have a NEON screwdriver recycle it in the bin, they will glow at under a hundred volts so can be very misleading.
By the way if you have a NEON screwdriver recycle it in the bin, they will glow at under a hundred volts so can be very misleading.
Chris,
don't throw it away just yet. Most commercial neon indicators are only designed to show the presence of live electricity form about 50v so can be useful to identify wires in walls etc for the decorator.
don't throw it away just yet. Most commercial neon indicators are only designed to show the presence of live electricity form about 50v so can be useful to identify wires in walls etc for the decorator.
Ian, a little confusion here I think.
The proximity detectors are fine as they don't actually touch the conductor but the NEON tester has to be in contact with the conductor and can give misleading results especially when trying to fault find.
The proximity detectors are fine as they don't actually touch the conductor but the NEON tester has to be in contact with the conductor and can give misleading results especially when trying to fault find.
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