haddock2685 Posted July 29, 2016 Share Posted July 29, 2016 Hello All Please be gentle with me... I'm not that technical and am on quite a steep (electrical) learning curve here. I purchased a little while ago a 'polarity tester' for an upcoming trip to France. When I originally tested it on our motorhome hooked up at home all three lights came up showing a correct supply. Since then a couple of things have happened; firstly the motorhome went into the suppliers workshop to have a bike rack fitted, then subsequent to this, the hydraulic slave unit on the clutch failed and the motorhome has been into Adams Morey (Portsmouth - highly recommended) to be repaired. We went away last weekend and on testing the polarity on-site, found that it was reversed. I thought nothing of this until I plugged the polarity checker in whilst I was hooked up at home and it is still showing reverse polarity in the 3 pin sockets in the van. I have checked the socket that the hook-up lead is plugged in to and this reports a normal supply. My question is, what could have changed on the internal electrics in our motorhome to cause the polarity to now be reversed? Or could it be something to do with the cable? I’d be most grateful for any guidance that you might be able to shed on this. Regards Alan Link to comment Share on other sites More sharing options...
EJB Posted July 29, 2016 Share Posted July 29, 2016 Hopefully you will get lots of good advice .......however there are many, including myself, an ex spark, who totally ignore 'reverse polarity' as it has, and never will, cause any problems! Good luck :-D Link to comment Share on other sites More sharing options...
Charles Posted July 29, 2016 Share Posted July 29, 2016 I made a tester just to see how many French and Spanish sites are reversed. Turned out it was about 50/50. It doesn't matter at all. Link to comment Share on other sites More sharing options...
spospe Posted July 29, 2016 Share Posted July 29, 2016 Some vans have in-built polarity correction facilities and perhaps yours is one of them. Do you have all the conversion information that should have been supplied with the vehicle? A god read of this should tell you if your van has the polarity correcting feature, if it has then something has happened to upset it and it needs sorting out.. Reverse polarity can cause some equipment to malfunction, such as Eberspacher heaters not to run on the electric heating section and Thetford electric hotplates to indicate they are switched on, even when they are not (had both these things happen). I would suggest your dealer as a first call if you do not feel confident of sorting it out, as something has clearly gone wrong and may possibly be the tip of an unpleasant iceberg. Link to comment Share on other sites More sharing options...
Brian Kirby Posted July 29, 2016 Share Posted July 29, 2016 The most important thing is that your tester shows a good earth. That is your fail-safe protection against shock, and it would be unwise to use any connection where an earth is absent. I can't see any reason why fitting a bike rack, or changing a clutch slave cylinder, would involve any interference with the 230V system on your van. Do you have more than one EHU cable, and might you have used one when first at home, and the other when on site and after your subsequent return? If so, I'd suspect that either the plug or socket on one of them has its polarity reversed. Whether there is any risk from reversed polarity depends on the electrical installation in your van, and what you do. There used to be a perceived risk when some internal lighting was mains fed, but only if a mains lamp failed and was removed, and someone then tried feeling for the lampholder to replace the lamp with the light still switched on. The danger was fingers straying into the now empty lampholder and touching the exposed contacts. Unlikely, but apparently it happened! 12V lighting is now the norm, and eliminates that risk. Second, there could be a risk if an appliance plugged into one of the mains sockets failed and someone attempted to investigate why with the socket switched off but with the appliance still plugged in. With reversed polarity live and neutral are transposed, so the feed becomes the unswitched neutral wire rather than the switched live wire, so the appliance remains live even though the socket switch is off. Always unplug before any intervention into any electrical appliance. Some sockets are unswitched, as I suspect yours may be. The risk of intervening with an appliance plugged into these is perhaps more obvious, and the warning regarding first unplugging no less relevant. The above risks will be almost eliminated if your van has a residual current device (RCD) as its mains switch (on the small consumer unit, usually sited near the point where the EHU plugs into your van - frequently buried at the back of a wardrobe!). An RCD should be recognisable from a "test" button (that should periodically be tested) beside the switch, that will trip the main switch when pressed. Were you to contact a live 230V wire in your van the RCD would "see" the current leaking through you, and cut the supply within milliseconds. A normally healthy person will be uninjured, though they will know they have suffered a mild shock. However the same is not true for those with certain heart conditions, or those fitted with pacemakers, where the outcome can be serious. So, as above, always unplug first, just in case. So, providing normal electrical safety precautions are observed there is no actual risk from reversed polarity. Even if those precautions were overlooked in the heat of a moment, providing you are normally healthy, the risk from electrocution would be virtually eliminated by an RCD mains switch. Your Burstner should have an RCD, and should also have double pole circuit breakers (MCBs, sometimes still referred to as fuses) for its 230V circuits (there is a variation that combines the two into one unit, called an RCBO, which performs both functions). If this is the case it will conform to normal continental wiring practise and will be "polarity blind". If you can get this confirmed you can forget all about reversed polarity, and relegate your tester to just checking for a good earth connection. Just don't play with anything electrical while is is plugged into a socket, and don't play with the van's electrics while it is on EHU, and you'll be fine! The only added risk from French electricity is that it smells of garlic. :-D Link to comment Share on other sites More sharing options...
PJay Posted July 29, 2016 Share Posted July 29, 2016 haddock2685 - 2016-07-29 4:05 PM Hello All Please be gentle with me... I'm not that technical and am on quite a steep (electrical) learning curve here. I purchased a little while ago a 'polarity tester' for an upcoming trip to France. When I originally tested it on our motorhome hooked up at home all three lights came up showing a correct supply. Since then a couple of things have happened; firstly the motorhome went into the suppliers workshop to have a bike rack fitted, then subsequent to this, the hydraulic slave unit on the clutch failed and the motorhome has been into Adams Morey (Portsmouth - highly recommended) to be repaired. We went away last weekend and on testing the polarity on-site, found that it was reversed. I thought nothing of this until I plugged the polarity checker in whilst I was hooked up at home and it is still showing reverse polarity in the 3 pin sockets in the van. I have checked the socket that the hook-up lead is plugged in to and this reports a normal supply. My question is, what could have changed on the internal electrics in our motorhome to cause the polarity to now be reversed? Or could it be something to do with the cable? I’d be most grateful for any guidance that you might be able to shed on this. Regards Alan Hi Alan We use Adams Morley for our MOT and service, have done for 8 years. Always very helpful. Maybe your van was always that way?. PJay Link to comment Share on other sites More sharing options...
haddock2685 Posted July 30, 2016 Author Share Posted July 30, 2016 Hello All Many thanks for your responses and ideas. My findings/thoughts so far based on your feedback are: @spospe – I’ve been through the van manual electrics section in detail and can find no mention of a polarity correction facility. Given how thorough the manual is in other areas I am 99% sure I don’t have one. @Brian I’m pretty sure I have an RCBO as the box has the main RCD with a test switch and 2 other circuit breakers alongside, so from that perspective I’m pretty protected. It’s the same EHU cable that I’ve used for everything. It’s only 4 months or so old and I wouldn’t have expected it to fail just yet. As per my original post, I’m 99% sure that when I originally checked the polarity tester it was reporting a correct supply in the van with 3 lights whereas it’s now reporting reversed polarity. Something has changed since, though I take your point about it being unlikely that it was the fridge or clutch work that caused the change. My confusion now is that my mains supply from the house is reporting a normal supply, but by the time it gets inside the van, its polarity is reversed and I’m sure this was not previously the case. I’m going to borrow a friends EHU later today to eliminate the cable as part of the problem, otherwise I’m going to have to pay a ‘sparky’ to check everything as I don’t like unexplained changes! Again, thanks for all your help. Regards Alan Link to comment Share on other sites More sharing options...
Robbo Posted July 30, 2016 Share Posted July 30, 2016 So, what work did you have done to the fridge? You only mentioned bike rack and clutch in you original post !!! Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 30, 2016 Share Posted July 30, 2016 This is the situation as I understand it... 1: When Alan purchased a 230V socket-tester he checked the tester’s functionality by connecting his Burstner Ixeo to his home’s domestic mains power supply and plugging the socket-tester into the motorhome’s 230V socket outlet(s). The socket-tester’s three lights illuminated indicating that no faults were present. 2: Now, when Alan connects his Burstner Ixeo to his home’s domestic mains power supply and plugs the socket-tester into each of the motorhome’s three 230V socket outlets, the socket-tester’s lights indicate the presence of ‘reverse polarity’ at all of the motorhome’s socket outlets. 3: When Alan plugs the socket-tester into the domestic 230V socket outlet that he is using to connect the motorhome to, the socket-tester’s three lights illuminate indicating that no faults are present at that socket outlet. As far as I’m aware there is no commercially-available equipment that will automatically ‘correct’ a reversed-polarity 230V power supply, though manual detector/changeover switches are marketed. http://www.homesteadcaravans.co.uk/accessory-shop/caravan-motorhome/electrical/230v-electrics/nova-mains-polarity-changeover-switch.htm Assuming that the socket-tester itself is OK (!!!), as the socket-tester confirms that the domestic 230V socket outlet is fault-free, the obvious thing to check will be what is connecting that outlet to the motorhome. If I connect my own motorhome to my home’s domestic 230V supply I employ one of two methods. Method One involves plugging the hook-up cable that I use at campsites into the motorhome's mains 230V inlet and fitting an adapter to the hook-up cable’s other end that allows it to be connected to a UK-norm domestic 230V 3-pin socket outlet in my garage. Method Two involves pliugging an ordinary 230V extension cable into a 230V 3-pin socket outlet in my garage, with an adapter at the ‘motorhome end’ of the extension cable that allows connection to the motorhome’s mains 230V inlet. Alan is apparently using Method One. As Brian says, there’s seems to be no logical link between the bike-rack/clutch (and fridge?) work and the polarity reversing. The prime suspect must be the cable and/or adapter that Alan is currently using to connect his motorhome to his home’s fault-free domestic 230V socket outlet. Checking polarity at the end of the cable that plugs into the motorhome's mains 230V inlet should confirm whether the problem lies with the cable/adapter or within the motorhome itself. If the cable/adapter proves to be UK-norm polarity-wise (and there’s no means within the motorhome to switch the 230V supply’s polarity) then something odd is going on. I think P Jay is suggesting that the 230V socket outlets in Alan’s motorhome may have always provided a reverse-polarity output even when the polarity of the 230V supply reaching the motorhome is not reversed. Assuming that those outlets are UK-norm 3-pin sockets (and I suspect Alan would have said if they were not) it would be expected that the motorhome converter would have ensured that the sockets were ‘UK normalised’ regarding their polarity. Alan has said that all three of his motorhome’s socket outlets now have reverse polarity: he hasn’t said that he originally tested all three of the socket outlets (and found their polarity to be ’normal’ with the socket-tester’s three lights all illuminating), but it’s likely that he did. I hesitate to suggest this, but are Alan’s socket-tester’s lights warning of reversed polarity or of a different electrical fault? It would be very peculiar for the motorhome’s 230V electrical system to have somehow reversed its polarity since Alan originally carried out the original ‘at home’ check, but a fault may have developed, or been introduced, into the system since then and this is now being registered by the socket-tester. (Clutching at straws, as 3-light socket-testers are clearly marked regarding what the light-sequence indicates.) Link to comment Share on other sites More sharing options...
haddock2685 Posted July 30, 2016 Author Share Posted July 30, 2016 All Given the location of the fridge in my van (on the rear wall) and how the bike rack has been mounted I have assumed that the fridge was removed to allow the fitting of the bike rack. I will try to confirm this with the supplier on Monday. If they did remove it, could it have been reconnected incorrectly thus causing an issue? @Derek – an excellent summary of my situation. I’ll try you extension cable ‘method 2’ to see what happens there. Updates as I get them. Many thanks all. Alan Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 30, 2016 Share Posted July 30, 2016 haddock2685 - 2016-07-30 9:12 AM ...If they did remove it, could it have been reconnected incorrectly thus causing an issue? I wouldn’t have thought so. I’d expect your motorhome’s 230V socket outlets to be powered directly via a cable from the ‘consumer unit’ and protected by one of the two circuit breakers you mentioned earlier. If that’s the case - and as your tester indicates that all three of the socket outlets have reversed polarity - there would be reversed polarity at the consumer unit. If it were then confirmed that the mains power-supply entering the motorhome at its 230V inlet did not have reversed polarity, the logical conclusion would be that the polarity has been reversed between the 230V inlet and the consumer unit. Dunno - but check the connection cable/adapter first. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 30, 2016 Share Posted July 30, 2016 Alan I’ve rethought this... Does your handbook identify what equipment the two circuit breakers in the 230V consumer unit protect? If one of the circuit breakers protects the fridge AND the 230V socket outlets, and the supply-cable leads from that circuit breaker to the fridge and then on to the socket outlets, there’s a real possiblity that - if the fridge needed to be moved and the 230V supply to it needed to be disconnected - reconnecting the supply could result in reversed polarity at the socket outlets. If your fridge’s lower exterior ventilation grille is removed, you may be able to see how the 230V supply is connected to the fridge. If this involves a ‘connection-box’, it would be worth opening this if you can (with the motorhome off hook-up!) and inspecting the wiring inside. You might find that the cables inside have been misconnected so that, even if the polarity of the 230V supply to the connection-box has the ‘correct’ polarity, the supply-cable(s) exiting the connection-box have been connected so that their live and neutral wires are reversed. (You could check the polarity of the 230V supply entering the connection-box, but you’d need to put the motorhome on hook-up to do this and be careful.) Link to comment Share on other sites More sharing options...
Robbo Posted July 30, 2016 Share Posted July 30, 2016 I would strongly suggest that the OP adds one of these to his toolkit (see pic). It is an adaptor from 3 pin UK to 3 pin male blue plug. Insert tester in 3 pin square and other end in EHU cable. Also very handy for testing electrical bollards on campsites. Link to comment Share on other sites More sharing options...
haddock2685 Posted July 30, 2016 Author Share Posted July 30, 2016 All Derek - tried your method 2 and I still get the reverse polarity in the van. I've checked the connections in my 3 pin to blue end converter and they are correct. The problem is as far as I can tell now, in the van. I've had the bottom grill off and the wiring looks sensible to my untrained eye. There is no connection box as such, just a couple of plug together blocks which as far as I can tell by limited fiddling only connect one way round. One for the supplier on Monday methinks. Need to get it fixed before September as that's when we toddle of to France for the first time. Don't fancy connecting a French reversed polarity site to a van that then reverses it again! The mind boggles at the result. Again, many thanks for all your help. Robbo, I will certainly get the bit you suggest, looks useful. Regards Alan Link to comment Share on other sites More sharing options...
EJB Posted July 30, 2016 Share Posted July 30, 2016 Don't worry one reverse polarity would cancel a second one out. Some people actually make up leads by reversing the connections thinking it will make a safe connection even safer *-) :-D Link to comment Share on other sites More sharing options...
Will86 Posted July 30, 2016 Share Posted July 30, 2016 I don't think anyone has asked if Haddock has his coloured wires the wrong way round? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 31, 2016 Share Posted July 31, 2016 Robbo - 2016-07-30 11:21 AM I would strongly suggest that the OP adds one of these to his toolkit (see pic). It is an adaptor from 3 pin UK to 3 pin male blue plug. Insert tester in 3 pin square and other end in EHU cable. Also very handy for testing electrical bollards on campsites. I wasn’t aware that the design of adapter shown in your picture existed, though I note that they are in fact fairly widely available (example here) http://www.electricaleurope.com/en/ESR-16A-2PE-Plug-to-13A-UK-3-Pin-Socket-Converter-Adapter/m-2669.aspx The adapter I use is similar to this http://www.ebay.co.uk/itm/Ceeform-Caravan-Plug-13A-3-Pin-to-Trailing-UK-Mains-Socket-Commando-Adaptor-CEE-/361465577770 I made up mine, but various versions (with one or more UK-norm 3-pin sockets) are marketed. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 31, 2016 Share Posted July 31, 2016 haddock2685 - 2016-07-30 1:08 PM All Derek - tried your method 2 and I still get the reverse polarity in the van. I've checked the connections in my 3 pin to blue end converter and they are correct. The problem is as far as I can tell now, in the van. I've had the bottom grill off and the wiring looks sensible to my untrained eye. There is no connection box as such, just a couple of plug together blocks which as far as I can tell by limited fiddling only connect one way round. One for the supplier on Monday methinks. Need to get it fixed before September as that's when we toddle of to France for the first time. Don't fancy connecting a French reversed polarity site to a van that then reverses it again! The mind boggles at the result. Again, many thanks for all your help. Robbo, I will certainly get the bit you suggest, looks useful. Regards Alan Alan There’s little point in trying to investigate this ‘by eye’. You have confirmed with your circuit-tester that the domestic 13A 3-pin socket-outlet that you are using to hook-up your motorhome is fault-free (ie, the circuit-tester’s three lights are all illuminated). However you do it, you next need to confirm that, when the circuit-tester is connected to the end of the cable (or cable-adapter) that is to be plugged into your motorhome’s 230V inlet, the circuit-tester’s three lights also illuminate. If that happens, you’ll KNOW that the cause of the sockets in the motorhome showing reversed polarity is within the motorhome. In your initial posting you said "I purchased a little while ago a 'polarity tester' for an upcoming trip to France. When I originally tested it on our motorhome hooked up at home all three lights came up showing a correct supply.” but you later said "I’m 99% sure that when I originally checked the polarity tester it was reporting a correct supply in the van with 3 lights whereas it’s now reporting reversed polarity.” You need to remove the 1% possibility that (as P Jay suggested) the motorhome sockets have always had 'reversed polarity’ and you misread what the circuit-tester showed when you originally tested the sockets. I’ve hypothesised that, if the fridge’s 230V power-supply had needed to be disconnected when the bike-rack was fitted, reconnection might have caused the sockets’ polarity to change if the fridge and sockets are on the same electrical circuit, but this is just crystal-ball gazing. If there’s nothing in your handbook to indicate what the circuit breakers protect, you could experiment. If you hook-up your motorhome and plug your circuit-tester into one of the motorhome’s sockets and then switch off each circuit breaker in turn, you’ll be able to establish which circuit breaker protects the sockets. Next switch back on the ircuit breaker that protects the sockets and choose 230V operation on the fridge. Once the fridge is operating on 230V, switch off the ‘sockets’ circuit breaker off and see if this stops the fridge operating. If the fridge stops working on 230V it’s logical to assume that the fridge and sockets are on the same circuit. If the fridge still works on 230V when the sockets do not my hypothesis was wrong. As EJB advises, multiple ’polarity swapping’ should not be a safety issue (and, as I’m sure you are aware, hooking-up to a reversed polarity 230V supply is also most unlikely to be a safety issue or have technical knock-on consequences). I recall connecting my Herald motorhome to a disreputable single-outlet 230V supply at a French ‘aire’ one evening and (because I was a novice motorcaravanner then) carefully checking using a circuit-tester that the polarity at the motorhome’s 3-pin sockets was ‘correct’. The following morning the circuit-tester’s lights showed reverse polarity and the reason was that a French motorhome had arrived late the previous night and connected a ’splitter’ to the supply-bollard so that the 230V power could be shared and the splitter’s wiring reversed the supply’s polarity. After that I didn’t care about reversed polarity, though I do check that a campsite/aire 230V supply is OK earth-wise or, if I need to use a long hook-up cable, that a 230V supply is actually operational before connecting to it. Best that you do get someone to look at this, though. If the ‘polarity' of your hook-up cable is OK and the ‘polarity’ of your motorhome’s sockets has reversed since work was carried out on the vehicle, then something has caused this to happen. Although reversed polarity at the sockets won’t be dangerous, if your hook-up cable is ‘correct’ polarity-wise, your motorhome’s UK-norm 230V 3-pin socket-outlets ought to have UK-norm polarity. Link to comment Share on other sites More sharing options...
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