Nigel DonnellySee other Advice articles filed in ‘Electrics’ written by Nigel Donnelly
Reversed polarity describes the situation where the live and neutral feeds in the hook-up bollard on a continental caravan site are switched. It makes no difference to continental tourers which are set-up to cope with it, but it can cause a safety issue for UK caravans.
Does reverse polarity cause a problem?
Appliances connected to the mains supply will still function in most cases. In older caravans however, there can be a problem. Potentially, appliances and fixtures can remain live, even if the power switch is turned off to them. For example, the metal collar around a light fitting could be live, even when the power is off. So appreciably, it could be dangerous.
How do I know if I have reverse polarity?
You need a mains socket tester. This is plugged into a mains socket in the caravan and it lights up if there is a problem, either with reversed polarity or some other issue such as a faulty earth.
What can I do about it?
If you have a caravan built after 1993, it’s less of a problem as the main circuit breakers are double pole units. This means that if the supply remains in place to the appliance and you touched something live, the system would trip out. It’s still not ideal though.
If you are not confident in your ability to complete this job, you should engage the services of a qualifed electrician or a caravan workshop.
The best solution is to detect the suspect supply and correct it. To cope with all eventualities, you need a spare continental adaptor which you can convert. Carry it with you to the continent and use it if required.
5 facts about reversed polarity
- It very rarely occurs on UK sites
- Most appliances will work, although they may not turn off properly
- Two-pin Euro connectors and three pin ‘blue’ sockets can be affected
- Post 1993 caravan electrics detect and cope with reversed polarity
- It can be corrected with a simple home-made adaptor