Provide power from the towbar to the lights on a trailer or caravan.
If towing a trailer these are the electrics you need.
Caravans can be towed on these electrics but the fridge won’t be powered.
If you are using the towbar for a cycle carrier you will need a single electric socket
fitted so that you can power a lighting board.
Two sockets are fitted as standard.
If you are towing a caravan built before 2008 the extra grey socket provides power
to operate the interior electrics of the caravan e.g. interior lights, run the fridge
and charge the battery while you are towing.
This type of socket has now been replaced on caravans built after 2008 in the UK.
New caravans use the 13 pin standard socket shown below
13 pin Electrics
These electrics have been standard in most other European countries for some time.
13 pin electrics replace the 2 separate socket currently used in the UK.
All caravans manufactured in the UK from 2008 are fitted with a 13 pin connector
13 pin sockets are also used on some vehicles with detachable towbars when there
isn't enough room to mount two separate sockets behind the bumper.