Electric keeps tripping

[Lisa A]

My caravan has been in indoor storage all winter and is now on a seasonal pitch. When I plugged in the electricity and turned on the fridge the power tripped the site box. A caravan repair guy said it was the fridge, which needed a new heating element. I have brought the fridge home to repair. However, on Monday I returned to the caravan and all was well with the electric. Heating worked all afternoon, boiled kettle, used microwave (one at a time so not to overload system). Only other thing on was the coolbox. Then at midnight the power tripped again. Nothing additional had been turned on, just heater and coolbox running. Even after resetting trip electric did not return. Any ideas where to start searching for the problem?

 

[Woodentop]

Most caravan mains items - fridge, microwave etc - are fed from a 13A socket near the item. Just unplug them all and watch what happens, then if the mains does not trip start reconnecting them until you find which is at fault.

It would be useful if you defined whether it is an MCB or the RCD that is tripping. (The RCD is the breaker with a test button.)

 

[Martin_E]

Also if you have an electric hob ring try unplugging that, it’s one thing most people forget, but can cause issues, along with the kettle

 

[Lisa A]

In the caravan it was the mains switch on the left that tripped. In the site box it was the blue switch that tripped. No other switches moved.

 

[Woodentop]

These are both RCDs which suggests a wiring or (specifically) and earthing problem. The fact that both tripped on one occasion is because the two RCDs would be fighting over the trip current.
Get an electrician (does not need to be caravan specialist) to check it over.

 

[Andy Norfolk]

I know very little about electrics. But is it worth running your cable to a different site box if it's long enough. Just to eliminate that it's not a fault on the site connection.

 

[Woodentop]

If it was a on the site connection the caravan RCD would not trip. An RCD only protects circuits that are after the unit, i.e. the pillar RCD protects the EHU cable, the caravan RCD protects the appliances in the caravan.

 

[ProfJohnL]

Intermittent electrical faults are always the most difficult to resolve, so usually you need to a systematic approach to them. This often means testing each component individually. Unless you are an electrician it's unlikely you will have the correct equipment to be able to check all the essential criteria of each appliance or fitting.

I think I would start with the mains hook up cable, then the RCD, but the fact that two RCD's have tripped does suggest the problem is more likely with one of the appliances.