How to use an RCD 10-15 Amp Power Adapter - Common problems and pitfalls

Author: Nadia  

What is an RCD unit and what does it do?

A Residual Current Device constantly monitors the electrical current running through a power circuit to protect you and your home or Recreation Vehicle from large electrical surges that could result in electrical shock or fire.

A portable RCD until will allow you to connect a 10amp socket to a 15amp plug.

Why do I need one?

An RCD until will safely allow you to connect a 10amp socket to a 15amp plug.

Homes are generally hardwired for 10 amp/240 Volt power. While most hardwired recreational vehicles are hardwired to allow 15-amp power to run the internal appliances. If you want to run your caravan at home or even charge the fridge before a trip away, you will need some protection for your home circuit, otherwise, the caravan can draw more than the domestic circuit can provide. This will ‘short-out’ the domestic circuit breaker, i.e. your home.

What would happen if I ran too many caravan appliances at once?

Your RCD unit safety would activate and stop you drawing more than 10amps power. It would stop the power and identify there is item drawing too much current. This is what they are designed to do.

Why does the Power adaptor keep tripping? Is it broken?

This is a common situation that can happen to everyone. You hook up the power correctly and when you try to use one or more appliance and the RCD trips. You reset it the RCD and try to run the appliance, the RCD trips again. Why?

The problem is unlikely to be a faulty RCD. A faulty RCD will not trip if there is a power surge!

The most likely scenario is an appliance is drawing too much current or you have an earth on an appliance. The good news is your RCD is doing exactly what it was designed for! It just paid for itself.


When electrical items have a fault, it can cause them to draw power from a circuit without stopping. This will overload the socket and could cause an electrical fire.

This is what these units are purchased for. To enable you to safely connect to the domestic supply but not to draw too much power. They create a safe power environment for you and your family.

Common errors

These units will not allow you to draw more than your 10amp domestic socket.

A 10-amp to 15-amp converter will not convert a domestic circuit into a 15-amp power source.

People often buy these units in the false belief that they will convert 10amps into 15amps.

If I can’t turn 10amps into 15amps what are they for then?

They are used to safely connect a 15amp vehicle to a domestic 10amp power supply.

This would enable you to run an appliance such as your caravan fridge while at home. BUT you can only run appliances that use less than 10amps in this scenario.

For example, just your fridge, or just your toaster.

But not all your caravan appliances at once e.g. the toaster, heater, microwave and fridge.

How much power do domestic appliances use?

***Please note individual appliances vary and this is just a guide


Average Watts

Approx. Amps

Electric Kettle






Very Small Fan Heater



Small Pod Coffee Machine


4 Amps

Small Microwave


4 Amps

Toasted sandwich machine


4 Amps

Any 15amp commercial equipment

OVER is 2400

Over 10AMPS and will not work


You could switch one item on, or a couple of smaller appliances but if you turned on too many things and it drew more than 10Amps the safety cutout would activate and shut off power.

And remember, these units are not appropriate for use with commercial equipment that uses over 10amps.

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