Traditional Electrical Installation Guide

The following information is intended as educational only, and will allow the DIY builder to source the parts required for a 240V electrical installation in a Recreational Vehicle. Government regulations insist the installation must be done by a qualified electrician.

Above: The traditional wiring where lights operate on 240volts

Extension Lead

You will need a 15amp Extension Lead to supply 240V power to your RV.
These are identified by a wider than usual earth pin, to prevent substitution with a 10amp extension lead. The wire within the 15amp cord is rated higher and allows for the flow of more electricity than a 10amp cord.
Modifying a 10amp cord with a 15amp plug should definitely not be done. Even a 'heavy duty 10amp cord' should not be used.

Power Inlet

Power Inlets come in different styles and colours.
Ensure you use one with a cover for external use, and rated at 15amps. If you have more than one circuit in your RV, you will need extra Power inlets.
The connections at the rear must be covered and the Active or Live (red or brown) and the Neutral (black or blue) wires should then go directly to a double pole circuit breaker.

Earth Connections

One earth wire coming from the power inlet must go directly to the chassis and be connected with a Bolt, Nut, and a Spring washer.
A second earth wire should then go to all power points, hard wired appliances, and any lights with an earth connector.
The wire should be at least 2.5mm and is normally green or green/ yellow. (Shown below as white for easy identification in some photos).

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Circuit Breaker

You are legally required to provide (at least) one double pole circuit breaker for each separate circuit in your RV.
These are rated at 16amps. RV's with air conditioners typically have a second circuit.
Larger RV's with many appliances may even need three circuits. Both the Active and Neutral go through the circuit breaker, so both are disconnected when the circuit is broken.
The Earth does not go through the breaker and must be uninterrupted to each power point, hard wired appliance, and 240V light fitting.

Residual Current Device (RCD)is a circuit breaker with the added safety of cutting off the current when a leakage to earth is detected from between HOT side and Neutral side.
A Circuit Breaker Cover is required to mount the breaker in. It contains two parts - the rear rack and the front cover. It is screwed to an inside wall or inside a cupboard. The breaker is then placed in the rack and wires attached, the front cover secured.

Switches

Each hard wired appliance and 240V light fitting requires a double pole switch.
Some lights already have their own switch - it must be double pole.
Switches are generally purchased with a cover as a complete single or twin switch.
Even where a Range hood contains its own switch, an additional isolating switch is required away from the stove top.

Power Points

The power points we sell have double pole switches.
They can be connected in series (one after the other) with the 3 wires terminating at the last power point.
Where the walls contain a cavity, you can generally use the low profile power points. There are mounting plates and DEEP power points also if there is a problem with wall thickness.
An external power outlet (e.g. in the annex) can be added to this series.
The number of appliances connected to power points on one circuit that are used at one time should be limited to the 16amps of the circuit breaker.

Wiring Locations

240V sheathed wire can run through the walls.
Where timber wall studs are 19mm square (photo shows a camper trailer wall which are 42 x 19mm) some stepping or offsets should be used to prevent wall being weakened along a straight line of drill holes.
Where aluminium or steel frames are used, grommets must be used to prevent vibration wearing a hole through the insulation.
If not housed in a wall, all 240V wire must be in conduit. 240V wiring must not be under the floor.

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Outlets

Backing blocks should be placed in wall cavities and all wiring tested before cladding is installed.
It may be a good idea to take photos of wiring to ensure no screws or drills pierce the wiring once the cladding is installed.

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A registered electrician will be required to certify any 240V installation in a new motorhome. As government rules and regulations can vary at any time, this information page should be read in the manner in which it was intended. It is not intended as a replacement for a qualified electrician.