Reverse Polarity is nothing to do with your compass pointing in the wrong direction! It is something that tin can happen when you plug into the Electric Claw Up (EHU) on a caravan site. It is unusual for it to happen in the Great britain, it is more likely to happen when touring on the continent. So what is it and how does information technology affect you lot?

Reverse polarity is quite easy to sympathize and in one case you lot know about information technology, information technology's fairly piece of cake to right. Simply, it is the live and neutral wires are the wrong way round on the EHU bollard.

" Wow… that was some error past the electrician that wired it up wasn't information technology? " Well, not quite. To understand how the state of affairs comes about nosotros need to go back in history a flake. When electricity was get-go started to be distributed and sold on a commercial-scale, all the switches had two poles… a live and a neutral, and so when you switched something on, both alive and neutral were connected at the same time. Conversely, when you switched something off, both live and neutral were asunder. Quite simple really and quite prophylactic. And so we and the rest of Europe carried on switching both wires. At some point, some bright spark (excuse the pun) said… "Hey, we tin can save some coin here on switches. Lets make them so they only have to switch the live on and off… exit the neutral connected" To make certain we got it correct, we coloured our wires Red and Blackness so everyone knew which was live and which was neutral. Meanwhile in Europe… they said "…Pfft…." and carried on using 'two pole" switches and their cables stayed black and grey or white and greyness or blackness and white.

Nosotros became obsessed slightly and said "what if someone wires it wrong?… we meliorate put another cable in there" then we of a sudden gained an 'earth" cable… coloured dark-green for our protection. The electricians in Europe liked the idea of an earth cable so they had a yellow ane… or light-green depending in which state you were in. Now, the cable manufacturers were upwards in arms… "can we please agree on a color for this globe"… no understanding was made, then the manufacturers got smart and fabricated the earth cable stripey… green and yellow stripey to be exact. We saw the new stripey cable and thought "this is proficient" then nosotros went stripey likewise, and non to be out done we decided that Brown was the new Crimson and Blue was the new Blackness!

Now I may take only re-written history slightly there… just I think you can grasp what went on. Then here we are… Brown, Blue and Green & Yellow cables and switches that simply operate on the live (Brown) cable, While our continental cousins even so utilise White and Grey and Black… with a Light-green & Yellow striped world but chiefly switch both the live and the neutral.

So what goes on when you plug your caravan into a bollard?. Well, the current flows down the brownish wire to your circuit breaker, and then on to your socket and in to your appliance… lets say a toaster. It returns upward the Blue wire and back to the EHU bollard. When you switch off your toaster, it turns off the Brownish wire and stops the current flowing. If you turn it off at the socket on the wall, information technology still stops the current flowing down the Dark-brown wire. If you turn it off by flipping the little switch on the circuit breaker, it still stops the current flowing downwards the brown wire to all the sockets.

Now, if we plug into a continental bollard, that has the live and neutral the wrong fashion circular and nosotros wait over again at our toaster we see at that place is a problem. We plow the toaster off and this time the switch is on the neutral or return path, so when we switch it off, the element 'may' even so have a voltage present on information technology. If nosotros turn it off at the wall socket, again we switch off the neutral side of the circuit, so the toaster all the same might accept 240 volts going to information technology. Even if we switch it off at the circuit breaker… it will still might have 240 volts going to it.

Now 99% of the time, this is not a problem…. until that is, someone decides to put their fingers into the toaster for what ever reason…. they can touch a live element. So the toaster doesn't even demand to have a fault with it. It tin can still be potentially dangerous.

Keep At-home and Carry On

Don't get too panicky though! Modern caravans are fitted with and RCD (Residual Electric current Device)… It'southward the job of this fiddling device to check the current flowing in on one wire and out on the other. If information technology detects that more current is flowing in than out because it's leaking out somewhere – it switches off. The RCD doesn't really care what color the wire is that the current flows in and out on, information technology simply wants to run across the same on each wire.

Martindale CP201 250V Industrial Cheque Plug

At present how tin can we correct it? Well, checking for reversed polarity is easy and simple. All you demand is to purchase a "socket tester".  You can get them from diverse outlets, I have listed a few links at the lesser of the page. They are simple to apply and will normally have 3 lights on the forepart. Just look at the lights that are lit and they will have a characterization on the front telling you lot what each light ways. If it indicates anything that is not "normal",switch off your van'southward master switch and unplug from the bollard. If necessary, consult the site warden before you do anything else. I prefer to use a Martindale CP201 tester, so I can cheque the bollard earlier plugging my van in. If on the continent and you use one of the continental adaptor leads, you can check that earlier you plug your van in. I'll assume though yous are using i that plugs into the normal 13 amp household socket in your van.

Now, if it indicates reverse polarity, you lot must switch off and unplug from the bollard. Now we can right a reverse polarity bollard. The best style is to have a short lead, similar your 16 Amp EHU lead with the bluish plug and socket. This one but needs to be about a pes (30cm) long. The plug is wired up in the right way… chocolate-brown to alive, blueish to neutral and dark-green/xanthous to world. The socket at the other end however needs wiring up the wrong way… Brown to Neutral, Bluish to Live and Green/Yellow to Earth. If you are unsure about this, please go to your local qualified electrician, they will exist able to make it for yous for a minor charge. Information technology's amend to pay to take information technology done correctly than attempt it yourself and become it wrong. It is vitally of import that y'all marker the lead "Opposite Polarity Correction Pb" clearly and brand sure it stands out.

A notation of caution. At that place are some of these leads available via on-line sellers at a well-known trading site. The ones I accept seen are made with 1.5mm cable and are not actually safe to use at 16 Amps. They won't catch fire or melt, but they might warm up a flake at the full 16 amps.  Any EHU pb that is supplied with a new caravan must be fabricated of 2.5mm cable. I don't see any reason opposite polarity leads are any different. It is actually illegal to sell these "opposite polarity correction leads" in the Uk. Information technology is withal, not illegal to make one for your ain use.

If you are unsure nigh any aspect of reverse polarity and using a "reverse polarity correction lead" Ask a qualified electrician. If y'all take any doubts nearly your ability to brand one… don't… get your local qualified electrician to brand it.

Testers tin can be bought from these and other places: Maplin  |  Amazon  |  Pass  |

Post updated June 2012

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