Brian Kirby Posted June 27, 2011 Share Posted June 27, 2011 I think the point I was trying to make was.....................HAS ANYONE DIED.................HAS ANYONE NEARLY DIED................it dont help the hoi polloi if you just discuss potential risk *-) ................based on that!,.... none of us would leave home *-) .....................has it happened EVER????????..................then we the average Mr Joe bloggs can make a decision if the risk is worth it ;-) The problem with this line of thinking David, is that it misunderstands the nature of risk. All risk is, by definition, potential risk. Once it happens it becomes a certainty, no longer a risk. If you overtake on a blind bend, there is a risk you may hit a car coming the other way. The potential is only realised if the car is there, and you hit it; otherwise, you get away with it. To deal with the risk, you must first understand it. To understand it, you must assess three things. First, what is the nature of the risk event: i.e what might happen? Second, how severe a risk is it: might it merely cause expense, or physical injury, or death? Third, what is the likelihood of it happening? Having evaluated the nature of the risk, one must then consider whether it can be avoided, or whether it must be accepted. The subset to these issues is how, and at what cost? So, back to the blind bend. The risk event is a car crash. Its consequences are possibly death, probably injury, and almost certainly expense. Its likelihood is lowish, but depending on traffic: certainly not accurately predictable. Can it be avoided? Yes: don't overtake on blind bends! What is the cost of this action? Zero. So, easy-peasy, lemon squeezy, don't overtake round blind bends gets you home safely. Obvious innit? :-) Next, lets suppose the risk is not so obvious, like the issue of reversed polarity. Same approach: analyse the risk, then its probability, then its consequences. The first problem is that the risk cannot properly be defined. The (presumed) UK spec electrical installation in your 20 year old van presents a completely different set of risks than is presented by my four year van's German spec installation. All we know is that yours may present risk (so the risk can only be potential risk), but that mine should not (i.e. no risk at all). There are two risks: electrocution (unaffected in fact by reversed polarity), and fire, both potentially lethal. The nature of the electrocution risk to your installation depends on whether an ELCB (possible) or an RCD (improbable) was originally installed, or may have been installed later (possible for either, depending on when). These devices are designed primarily to protect the individual, not the installation. Since we don't know (though you may), we should probably assume yours has a simple on/off mains switch. Since this provides no automated cut off in the event of an earth fault, the risk for you and yours is electrocution. (In principle, at least, my RCBO will prevent me from being electrocuted if I inadvertently earth the system: nothing will do this for you: sorry! :-)). Your protection would, therefore, only come if the feeder pillar to which you connect is so protected, and whether the earth connection is adequate. It should be in both cases, but how reliably that may prove the case will depend on the age of the site installation, when it was last tested, which plonker last used (or abused) it, and which country you are in. How lucky do you feel? Beyond electrocution, there is the fire risk. This would arise if the electrical load on a circuit were greater than its wiring could sustain, so overheating the wires. Fuses, or MCBs, are installed to prevent the wiring overheating in this way, by being designed to blow, or trip, when the load approaches the wiring capacity. Here, we come to the potential reversed polarity problem. UK regulations call only for the fuse, or MCB, to be installed in the live feed (red) to the circuit, on the assumption this will always be the live. There is no such device installed in the neutral (black) return from the circuit, because this merely allows the current to flow to earth down wires of the same size as the live. Everything that leaves via the neutral must first have passed through the live and its protective fuse/MCB, so the one device protects both live and neutral wiring. However, if the polarity is reversed (as is quite common in the rest of Europe), the current will now flow into your circuits via the unprotected neutral wires, and will only meet the protective device as it leaves. That current now has the potential to cause mischief unchecked. If the problem is simple overload, the current will blow/trip the protection as it exits, so cutting the circuit, but all of the wiring up to the protective device will remain live, as will everything connected to the circuit. If you have switched sockets, you may just switch off, thinking you have made your appliance safe. You will not, because that switch operates only on the live side of the plug, and the current is now flowing the other way. Your appliance remains live, unless unplugged. So now, we are back to the electrocution risk. With reversed polarity, your circuit, and anything connected to it, are still live. Unless there is an ELCB, RCB, RCBO, or whatever, in that circuit, which isolates both live feed and neutral return (double pole, DP), the only way to safely sort out the fault that blew the fuse, will be to disconnect the site mains supply. The danger is that in the heat of the moment you may forget, and inadvertently touch something you believe isolated, but which is in fact still live, during your investigations. Now, you will provide the earth path and, in the absence of that DP mains isolator, will get a good, fat, belt! What happens next will depend on how good a path you provided, how the electricity passed through your body, and whether the shock caused you to recoil or paralysed you leaving you connected. See, uncertainties again, so more potential risks! :-) For all the above reasons, therefore, Derek and I, and others, (and, for what it is worth, the clubs) all say checking the supply for reversed polarity and the presence of an earth connection - which is a cheap, quick, easy, check - and then correcting polarity, and/or rectifying an absent earth by connecting elsewhere, is the only sound advice to give to anyone who doesn't understand the rudiments of electrical supplies, the nature of the equipment in their van, or the risks that may be presented. In the absence of knowledge, it is the only foolproof course to adopt. It is also the only safe advice to give on an open forum, where the knowledge of the readers, and the age and condition of the installations they may be using, are complete unknowns. The rest of this string has been an informative and interesting engineering debate, and should not be decried merely because knowledge, understanding, or attention spans, have been exceeded. We can all learn. Link to comment Share on other sites More sharing options...
Brambles Posted June 27, 2011 Share Posted June 27, 2011 Having read your last post Brain it has finally prompted me to respond. You make some good points. So in Summary I would say the following applies. Van with double pole RCB along with double pole current overload trip be it incorporated or seperate unit. ...reverse polarity is not an issue in UK or Europe. (Europe - meaning Continental Europe) Van has Single pole switching RCB or single pole current protection devices then in UK 'polarity' testing is important and live neutral reversal corrected. In Europe with (non tied to either live conductor) earth sytems then single pole protection devices are a definite no go and a double pole RCB and double pole over current protection devices MUST be fitted. If you do not know what you have then in UK check polarity. If you do not know what you have then In Europe, polarity testing and correcting may not protect you, and you MUST check you have a double pole RCB/over current protection fitted for max safety. No ifs and no buts, in Europe you must use double pole protection because of variable earthing sytems used. Polarity testing and reversing is not sufficient to give you max safety. You can get away with single pole in UK if polarity testing but not in Europe should a fault develop between what we call neutral and earth in the vehicle. Fortuately most motorhomes have double pole protection but from what some have been saying in their posts it sound like it might not be the case in older vehicles or UK built modern ones. So therefore in UK for those who do not know what they have or understand electricity, polarity testing should be carried out. In Europe there is only one stance, double pole protection is a MUST and reverse polarity testing is irrelevant unless a tied earth system. In UK you know they have tied earths (because I am telling you they do!!!!) , in Europe it varies from country to country and in some countries from area to area. So in summary (for a second time!) for max safety why bother buying a reverse polarity tester but instead fit an over current protection DOUBLE POLE RCB instead, if you do not already have, and then you do not have to worry. Link to comment Share on other sites More sharing options...
pkc Posted June 27, 2011 Share Posted June 27, 2011 pelmetman - 2011-06-26 10:26 PM I've lost the will to live after reading that lot (lol) ..........................please plug me into reverse polarity and finish me off (lol) (lol) I await your near death responses (lol) (lol) (lol) Likewise, PKC. R.I.P. Link to comment Share on other sites More sharing options...
Brian Kirby Posted June 27, 2011 Share Posted June 27, 2011 Brian Kirby - 2011-06-27 1:18 PM........................... We can all learn. Too late to edit. I should have added, but not all of us have the inclination. :D Link to comment Share on other sites More sharing options...
postnote Posted June 27, 2011 Share Posted June 27, 2011 Just buy the gizmo thing that tests the polarity and polarity leads from eBay. Oh so simple Link to comment Share on other sites More sharing options...
Guest pelmetman Posted June 27, 2011 Share Posted June 27, 2011 Brian Kirby - 2011-06-27 1:18 PM If you have switched sockets, you may just switch off, thinking you have made your appliance safe. You will not, because that switch operates only on the live side of the plug, and the current is now flowing the other way. Your appliance remains live, unless unplugged. So I don't need to buy a polarity tester then Brian :D ..................as all I need to do is to try to boil the kettle with the switch on the socket off ;-) Just for info................we have a ECLB/RCCD with 2 MCB's :D Link to comment Share on other sites More sharing options...
Robinhood Posted June 27, 2011 Share Posted June 27, 2011 pelmetman - 2011-06-27 7:01 PM Brian Kirby - 2011-06-27 1:18 PM If you have switched sockets, you may just switch off, thinking you have made your appliance safe. You will not, because that switch operates only on the live side of the plug, and the current is now flowing the other way. Your appliance remains live, unless unplugged. So I don't need to buy a polarity tester then Brian :D ..................as all I need to do is to try to boil the kettle with the switch on the socket off ;-) Just for info................we have a ECLB/RCCD with 2 MCB's :D ....with that level of understanding, best stick to gas! :-D So how about a nice discussion about gas safety - or perhaps not *-) Link to comment Share on other sites More sharing options...
Guest pelmetman Posted June 27, 2011 Share Posted June 27, 2011 Robinhood - 2011-06-27 8:32 PM pelmetman - 2011-06-27 7:01 PM Brian Kirby - 2011-06-27 1:18 PM If you have switched sockets, you may just switch off, thinking you have made your appliance safe. You will not, because that switch operates only on the live side of the plug, and the current is now flowing the other way. Your appliance remains live, unless unplugged. So I don't need to buy a polarity tester then Brian :D ..................as all I need to do is to try to boil the kettle with the switch on the socket off ;-) Just for info................we have a ECLB/RCCD with 2 MCB's :D ....with that level of understanding, best stick to gas! :-D So how about a nice discussion about gas safety - or perhaps not *-) So would my kettle not work then?........ :-S Link to comment Share on other sites More sharing options...
Brian Kirby Posted June 27, 2011 Share Posted June 27, 2011 pelmetman - 2011-06-27 8:55 PM.....................So would my kettle not work then?........ :-S On gas? Yes, perfectly. Link to comment Share on other sites More sharing options...
BGD Posted June 28, 2011 Share Posted June 28, 2011 postnote - 2011-06-27 5:31 PM Just buy the gizmo thing that tests the polarity and polarity leads from eBay. Oh so simple Even simpler: don't buy the gizmo; and don't worry about it. Link to comment Share on other sites More sharing options...
Brambles Posted June 28, 2011 Share Posted June 28, 2011 One thing for sure is it is gas is a heck of a lot more dangerous than electricity. Not sure about being being sufficated by gas and lets not re-enter the gassing topic again as all a myth, but certainly have been plenty of reported accidents and many fatal with gas exposions in caravans and motorhomes. Link to comment Share on other sites More sharing options...
Robinhood Posted June 28, 2011 Share Posted June 28, 2011 Brambles - 2011-06-28 1:23 AM One thing for sure is it is gas is a heck of a lot more dangerous than electricity. Not sure about being being sufficated by gas and lets not re-enter the gassing topic again as all a myth, but certainly have been plenty of reported accidents and many fatal with gas exposions in caravans and motorhomes. ........but that would be using that foreign gas :-S It's just not safe, you know B-) :D Link to comment Share on other sites More sharing options...
Brambles Posted June 28, 2011 Share Posted June 28, 2011 I think Robin, it depends what foreign food you ate the night before. Link to comment Share on other sites More sharing options...
Guest pelmetman Posted June 28, 2011 Share Posted June 28, 2011 REVERSE POLARITY Polarity, applied to mains hook-up, refers to the correct connection of live and neutral. The subject of reversed polarity is one that seems to cause some of the greatest concern, so let’s deal with it now. The blue site plug (along with British 13-amp plugs, French plugs, and the plugs used in many other countries) is designed to fit a socket only one way. Such plugs are said to be polarised. The Schuko plug, on the other hand, is reversible and will fit either of two ways. This means that when Schuko connectors are used it is impossible to guarantee which wire will be live and which neutral. For the majority of portable appliances used in Continental homes this is of no consequence. It is perhaps due to the general acceptance of this fact that even where polarised plugs are used, as in France, electricians do not seem to be too concerned about which way live and neutral are wired at an outlet. This extends to the blue IEC/CEE site outlets, where they are used. The problem arises when a system designed for British use, where the live and neutral are clearly defined, is plugged into a Continental power source. The problem is nothing like as great as many people believe, and the supposed dangers are frequently exaggerated to extremes. The only safety issue of any great concern is that fuses in the vehicle could end up in the neutral were they are unable to provide any protection against shorts to earth. All modern British motorhomes are fitted with an RCD, a type of earth-leakage circuit breaker, which monitors the current in both live and neutral conductors. The RCD provides the necessary protection against shorts to earth and will do so whichever way the supply is connected. SO FOR AN RCD EQUIPPED VEHICLE, REVERSE POLARITY IS QUITE TRIVIAL. With an older vehicle that does not have an RCD, a simple plug-in tester can be used to indicate whether the live and neutral connections are correct. If incorrect polarity is indicated, a Schuko plug can be reversed in the socket, but for other types of connector a short adapter lead with live and neutral deliberately crossed will be needed. A much better solution is to avoid all this trouble entirely and fit an RCD. Aside from the reverse-polarity issue, an RCD provides much better protection against certain other faults than fuses can, and for that reason along is to be recommended as a valuable aid to safety. And who would be so scandolus as to trivialize such a problem 8-) .......................MMM September 2001 (lol) (lol) (lol) (lol) It was an indepth article on continental hook up problems ;-) ...................which also pointed out that polarity testers are not quite the panacea to the problem and that you need to have some knowledge of how the wigglies work, or else you could be masking other potential problems!!..........................................................................but as the last sentence on a 2 page article reads......"So long as an RCD is in use there is nothing to worry about" :D Surprise surprise even a 21 year old banger like mine can be classed as "modern" as we have an RCD B-) AND NO :D ..........................I have not been trawling through old copies of MMM, it just so happened that Sue has been going through my draws 8-) ..........as part of our declutter prior to becoming "Of no fixed abode" B-) She also found several MMM's of 1986 vintage and 1 from 85 if anyone wants them please pm me ;-) Link to comment Share on other sites More sharing options...
Brian Kirby Posted June 28, 2011 Share Posted June 28, 2011 However, to be fair, Dave, the article you quote says exactly what a number of us on here have been saying, albeit with greater elegance (no doubt due to less rigorous editing! :-)), from the outset. The important proviso in the article is: FOR AN RCD EQUIPPED VEHICLE, REVERSE POLARITY IS QUITE TRIVIAL (their caps). Your van apparently is RCD equipped, and the OP's van is highly likely to be, but it cannot be guaranteed that everyone else's will be. Anyone can read these forums and, although I think anyone who takes advice from totally unknown people on forums whose advice may be completely wrong is mad, the insane do, apparently, exist! There is however a second proviso, not mentioned in your quotations (though I'd be surprised - because I suspect I know who the author was - if it was not originally stated). This is that the RCD is regularly tested and works. There is a potential danger if the neutral wire is broken before the RCD. That is to say if the neutral conductor in the hook-up lead is broken, or has become disconnected at either of the connectors. Under these circumstances the live will be intact through the RCD, leaving the installation live, but because of the missing neutral connection, the RCD will be unable to "see" an earth fault. The system will look as though it is dead, but will remain live, and the RCD test wont work. Link to comment Share on other sites More sharing options...
rupert123 Posted June 28, 2011 Share Posted June 28, 2011 peter - 2011-06-20 11:11 PM How would you know you were not earthed if standing on a m/h floor? what if you were touching any of the metalic parts of appliances that are mains powered, fridge etc. So you sugestion is stupid and dangerous. As for my qualifications, how about a 5 yr apprenticeship as an electrician in a propper company. Not in a prison as you seemed to suggest you were H.M.G. :D Been away so just seen your usual charming reply. I assume by my suggestion you mean the bit about the live wire. I did in fact say 'if you were daft or stupid enough to stick your fingers in a live socket' so hardly a suggestion. However as this was not the original posters question will let it pass. Seems a pity that the forum has just git rid of one member who threw insults around whenever someone disagreed with them and seems to have aquired another. Oh yes HMG, Her Majesty Goverment, in my case a royal dockyard. Link to comment Share on other sites More sharing options...
Guest pelmetman Posted June 28, 2011 Share Posted June 28, 2011 Brian Kirby - 2011-06-28 1:45 PM However, to be fair, Dave, the article you quote says exactly what a number of us on here have been saying, albeit with greater elegance (no doubt due to less rigorous editing! :-)), from the outset. The important proviso in the article is: FOR AN RCD EQUIPPED VEHICLE, REVERSE POLARITY IS QUITE TRIVIAL (their caps). Your van apparently is RCD equipped, and the OP's van is highly likely to be, but it cannot be guaranteed that everyone else's will be. Anyone can read these forums and, although I think anyone who takes advice from totally unknown people on forums whose advice may be completely wrong is mad, the insane do, apparently, exist! There is however a second proviso, not mentioned in your quotations (though I'd be surprised - because I suspect I know who the author was - if it was not originally stated). This is that the RCD is regularly tested and works. There is a potential danger if the neutral wire is broken before the RCD. That is to say if the neutral conductor in the hook-up lead is broken, or has become disconnected at either of the connectors. Under these circumstances the live will be intact through the RCD, leaving the installation live, but because of the missing neutral connection, the RCD will be unable to "see" an earth fault. The system will look as though it is dead, but will remain live, and the RCD test wont work. I take onboard where your coming from Brian, but I sometimes think trying to define every possible risk actually stops people employing common sense *-) .............and this potential risk falls into the same niche as "Caution Hot water" stickers placed on hot taps *-) It would probably help people reading this thread if we could narrow down the person who is likely to have a problem ;-) If we accept that what Paul Coxwell wrote in 2001 still holds, for it was his artical that I copied and it was me that used uppercase, as I wanted to highlight that part and I dont know any other way to do it , I fully accept that on a forum that is a "capitol" offence (lol) (lol) .......You will not have a problem...........As he said if you have a modern well maintained vehicle fitted with a RCD, and that means vehicles from the late 80's possibly earlier? as I can't be sure when manufactures started fitting RCD's. That seems to narrow down our potential victim :D ............someone in a clapped out old camper....... but he's still safe................unless he ventures abroad 8-) .............. some how his clapped out old camper gets him there.............but he's still safe.............until he finds a pitch with reverse polarity............but he's still safe.......then he plugs into the electric 8-) 8-) 8-) ....................but he's still safe..............OH!!! NO his kettle not working 8-) 8-) .......................So he takes it apart without unplugging the electric.................BAM!!!....................... He gets a electric shock 8-) .....................but as he's from the shallow end of the gene pool he picks himself up and unplugs the electric (lol) (lol) Link to comment Share on other sites More sharing options...
Brian Kirby Posted June 28, 2011 Share Posted June 28, 2011 Then, we'll just have to agree to differ. I think it is preferable to inform people as fully, and as factually, as possible, so that they can make their own decisions about what they want to do, on an informed basis. You apparently think this level of information may prevent them using common sense. I, on the other hand, don't see how they can use common sense, unless they have the facts. Somehow, something just doesn't seem to gel somewhere in someone's logic. Is this the new Catch 22? I give in! :-) Link to comment Share on other sites More sharing options...
Guest pelmetman Posted June 28, 2011 Share Posted June 28, 2011 Brian Kirby - 2011-06-28 9:26 PM Then, we'll just have to agree to differ. I think it is preferable to inform people as fully, and as factually, as possible, so that they can make their own decisions about what they want to do, on an informed basis. You apparently think this level of information may prevent them using common sense. I, on the other hand, don't see how they can use common sense, unless they have the facts. Somehow, something just doesn't seem to gel somewhere in someone's logic. Is this the new Catch 22? I give in! :-) I agree :D .....................but don't get me wrong Brian I think the info should be out there... but it is also useful to point out which kind of vehicles are likely to have problems...............Seems to me buying a polarity tester if you have a modern well maintained van with a RCD is unnecessary :D Link to comment Share on other sites More sharing options...
Brian Kirby Posted June 29, 2011 Share Posted June 29, 2011 pelmetman - 2011-06-28 9:36 PM Seems to me buying a polarity tester if you have a modern well maintained van with a RCD is unnecessary :D I'd be happier if that had said "Seems to me buying a polarity tester, if you have a well maintained van with a RCD and double pole MCBs, is unnecessary". Modern is too vague, and you only fully eliminate the small reversed polarity risk if DP MCBs are also present. But otherwise, for under £10, and for peace of mind, why take risks you may not understand? I have to say I really do not understand your objection to that simple piece of advice. Is that not common sense enough? Link to comment Share on other sites More sharing options...
Guest pelmetman Posted June 29, 2011 Share Posted June 29, 2011 A bit more of Paul Coxwell's article................. :D POLARITY TESTERS As you may have gathered by now, many of the problems encountered with Continental hook-ups are due to poor design and lax workmanship. Most European countries have their own standards, which are intended to ensure a safe, reliable electrical system, but these standards are not always followed. It is always somewhat risky to make broad generalisations, but on the whole people like the Spanish, Portuguese, and to a (slightly) lesser degree the French, seem willing to accept poor installations that would not be tolerated by the Germans, Danes or Swedes. The Continent does not have a monopoly on bad wiring, of course, and the rigours to which site installations are subjected mean that faults can occur in the best of systems. Always be alert for potential dangers such as broken sockets, damaged leads, and so on. The question of earthing is often raised, and this is one area where practice can differ considerably from one country to another. In some places (including the UK) the method used varies between districts, whether urban or rural, and to some extent depending upon the age of the installation. A poor or missing earth connection means that a fault may not blow a fuse or trip a circuit breaker, and could leave an entire vehicle bodywork live in some cases. If the earthing fault is common to more than one outlet, it is possible for your own vehicle to be affected by a fault on someone else’s motorhome. The possibility of a less-than-ideal earth connection is another reason for using an RCD, since it offers improved protection, but beyond that there is little that can be recommended for the average motorhome other than to avoid connecting to a system which is in any way suspect. Many people carry plug-in testers to check for common faults. These devices fit a 13-amp socket in the vehicle and indicate faults by a combination of three lights. Details vary slightly from one make to another, but a printed table usually shows the light combinations for a live/neutral reversal, missing neutral, missing earth, and so on. It is important to realise that these testers were intended for use by electricians to check for specific faults under controlled conditions. To anyone who does not understand their limitations and the way in which they work, the results can be misleading. For example, some devices can indicate a live/earth reversal (which would be extremely dangerous) when in fact the fault is a broken neutral on the hook-up. This happens if other equipment in the vehicle is plugged in during the test; disconnecting everything else yields the correct indication of no neutral. There are some faults, and combinations of faults, that the tester will not properly show, or which it may or may not show depending upon other circumstances. Use one of these devices to check for reversed polarity if you wish, but do not rely upon it too heavily for anything else. In some areas of Scandinavia a tester may give strange indications when there is no fault, no matter which way a Schuko plug is inserted. This is because some Scandinavian supplies have no neutral, both wires being equally live at 110 volts to make up the usual 220 volts, so reversing the connections will have no effect. So long as an RCD is in use, there is nothing to worry about. Which seems to me that we should only advise people to invest in a polarity tester if they have a working knowledge of electricity ;-) Maybe it's time for MMM to do another article on this subject :-S Link to comment Share on other sites More sharing options...
Guest pelmetman Posted June 29, 2011 Share Posted June 29, 2011 pelmetman - 2011-06-29 3:12 PM Maybe it's time for MMM to do another article on this subject :-S I wonder if Daniel is following this thread (?).......................As us followers of the "Thicko's charter" could do with a bit more clarification in the shallow end of the gene pool (lol) (lol) (lol) Link to comment Share on other sites More sharing options...
postnote Posted June 29, 2011 Share Posted June 29, 2011 pelmetman - 2011-06-29 4:46 PM pelmetman - 2011-06-29 3:12 PM Maybe it's time for MMM to do another article on this subject :-S I wonder if Daniel is following this thread (?).......................As us followers of the "Thicko's charter" could do with a bit more clarification in the shallow end of the gene pool (lol) (lol) (lol) And your point is? :D Link to comment Share on other sites More sharing options...
Guest pelmetman Posted June 29, 2011 Share Posted June 29, 2011 postnote - 2011-06-29 4:54 PM pelmetman - 2011-06-29 4:46 PM pelmetman - 2011-06-29 3:12 PM Maybe it's time for MMM to do another article on this subject :-S I wonder if Daniel is following this thread (?).......................As us followers of the "Thicko's charter" could do with a bit more clarification in the shallow end of the gene pool (lol) (lol) (lol) And your point is? :D Daniel is the esteemed editor of MMM ;-)................... hopefully he will commission an in depth review of the reverse polarity debate by an expert 8-)...................who can define the pro's and cons of having a polarity tester if you have no working Knowledge of electricity ;-)...................Unlike the CC who just automatically take the PC default route of recommending one *-) Link to comment Share on other sites More sharing options...
Brian Kirby Posted June 29, 2011 Share Posted June 29, 2011 Might be a very good idea to update the article. PM him and ask him what he thinks. In truth I think there are two, maybe three, people on here who have the breadth and depth of knowledge necessary to give definitive answers to all the possible combinations of potentially dangerous electrical inconsistencies, and the best ways to protect against them. I'm not one of them, which is why my advice to any other non-expert remains that if they are unsure what they have on board or how it works, getting, and using, a simple tester, and then correcting reversed polarity, or an absent earth, is the simplest, safest overall remedy. Our van, I have discovered after four years, has a double pole (I don't think single pole is made) RCBO, which seems to be the best overall remedy. Consequently, I have decided to completely ignore reversed polarity issues, and we only now test for a present earth, recognising that is a very rudimentary test that reveals little-to-nothing of the useful capacity or impedance of the earth connection. Just that there is a earth. What Coxwell describes, in terms of the limitations of these testers, are unusual circumstances (except the oddities of Scandinavia). For the potential risk from reversed polarity to become manifest, other unusual circumstances must come into play, either in the van, or the hook-up cable. So what we now seem to need, for his tester risks to present "real and present dangers" for a user, would appear to be for both sets of unusual circumstances to coincide. That is to say, the van with the dangerous characteristics must be taken to a site with the dangerous characteristics, and its owner must then misunderstand what the tester tells him, and go on to do something foolish with his electrical installation or appliances. This coincidence of risks and stupidity is clearly possible, so it cannot be totally discounted but, given the small probability that any one of the components of the overall risk package will manifest, the probability of all four factors manifesting simultaneously seems to me, at gut level, rather less than the chance of the sun spontaneously going out tomorrow at 10:45 precisely! :D And you were the guy who was arguing common sense should rule. :D So, as above, I simply give up! Really! :-D Link to comment Share on other sites More sharing options...
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