TECHNOFILE
LRM workshop
by Lindsay Porter
in association with MCL (Mobile Centre Limited)
So, you didn’t think that seven went into 13 exactly twice? Well, when it comes to caravan plugs and sockets it does! Lindsay shows how you can convert your caravan’s 12N and 12S sockets into a single, superior, 13-pin connection using parts from MCL Ltd.
Two Sevens are Thirteen Lindsay writes lots about caravans
and trailers as well as Land Rovers and these greatly improved 13-pin plugs – sometimes though not entirely accurately called ‘Euro’ plugs – are well worth fitting. So, here’s how to take two old, ‘black’ and ‘white’-type caravan plugs and convert them to a single ‘Euro’ plug. New Land Rovers and caravans normally come with the newer, 13-pin socket, unless you specify otherwise. Mind you, some new vehicles only come with the trailer cables connected to the 13-pin socket, not the caravan cables. If you’re buying new, check with your dealer. Incidentally, the MCL parts shown here are said to be ‘original equipment’ quality, not like some truly dreadful eBay tat!
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WHAT’S SO GOOD ABOUT IT?
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n Pins and sockets are stronger, and made from superior materials. (At least, MCL’s are – can’t speak for cheapo Chinese versions!) n The plug is positively engaged so can’t be wobbled, preventing pin deformation. n The plug locks positively and the flap on the socket clips over the disc on the plug only when correctly inserted. n 13-core cable has larger earth conductors than 7-core cables, reducing voltage drop.
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because, within the 12S socket, there are at least two unused positions. Picture 3 Before getting this far, you must make sure the vehicle battery has been disconnected (note alarm and ICE settings, etc). Tim used his tester to make certain he knew... Picture 4 …which wire was which. In theory, the colour code should tell you but you never can tell. He twisted and soldered each cable end before inserting each cable into its relevant hole…
IMPORTANT NOTE
Picture 1 MCL have several different types of adaptor available but of course, it makes life simpler if all your plugs and sockets can be of the same, 13-pin type. A and B are male/female adaptors; C and D, 13-pin plug and socket; E a stainless bracket and F cleverly allows a conventional tow-vehicle to power LED lights on a caravan. Picture 2 Tim Consolante from MCL demonstrated the ‘innards’ of the 13-pin socket. In essence, 2 x 7 (pins) make 13
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nY ou will need a wiring diagram in order to know which colours to connect to which pins. nT here have been a few (minor) changes over the years, so the best thing to do is download a suitable diagram from t’net. This will also tell you what to do with the two or three earth wires from the ‘old’ sockets – they DON’T all go to the same pin! n I f your trailer or caravan already has a 13-pin plug, match pins and colours on your new socket.
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Picture 5 …in the 13 pin socket. (He’d previously slackened each of the screws) The one downside is that there are almost twice as many wires to get into pretty much the same amount of space as before, so care is needed. PICture 6 MCL can also supply this wonderful, shrink-fit sleeving that tightens as it’s heated and also has sealant built in. Picture 7 The shrink-fit sealant melts then resets itself as it cools. Tim used stainless steel bolts and locknuts to attach the socket to the stainless steel bracket, available from Extreme 4x4.
Picture 8 If your caravan has two 7-core cables, MCL can supply this clever 13-pin adaptor plug which has two holes in the cable grommet (inset) allowing sealed entry for both cables. Picture 9 But what if you also tow a small trailer with single, 7-pin wiring? Simple! You purchase an inexpensive 13-to-7-pin adaptor, fit adaptor to socket and trailer plug to adapter. Picture 10 This is a caravan-mounted 13-pin socket, allowing you to remove the cable completely when parked up. And you can also see how a pair of cables enters the twin-cable 13-pin plug. LRM
CONTACT MCL (Mobile Centre Limited) For all electrical components shown here. Tim Consolante, PO Box 222, Evesham, WR11 4WT Tel: 0844 578 1000 www.mobilecentre.co.uk For stainless steel socket brackets: Extreme 4x4 Ltd. Tel: 01255 41141. www.extreme4x4.co.uk
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