Thread: Just purchased a new (second hand) expedition trailer - Wiring advice needed

As far as earthing of the 12v house side of things it is best to have everything wired with twin core and no earth.
If the light wiring for connection to the towing vehicle is using the frame/chassis as earth then that should be ok as long as the individual lights are earthed as well which might be hard if the trailer is made with non conducting materials. Personally I usually wire everything with twin core on the trailer as far as the lighting goes.
There's nothing wrong with the Enerdrive gear, much preferable than lots of other brands including Redarc.
With the 240v tripping you had best get a sparkie familiar with caravan/camper trailer/motorhome wiring to sort it.
Is the Enerdrive inverter a pass through one? If it is they have an inbuilt RCD.
The AC should also have an RVD instead or as well as a RCD as when the inverter is supplying AC there is no earth connection so the RCD will not work.

Everything should be "above earth" which means nothing to the frame at all. Enerdrive gear is good. And the charger sizes sound great.

Wiring can look crap sometimes. It's the terminations and wire sizes that are important. Get a house leco to look into the RCD issue. Or disconnect appliances one at a time, if you have the skills and expertise to do so safely

I use 6mm auto twin core double sheathed cable for everything in my car, camper trailer and now caravan . Just as easy as running a single core cable and then no issues finding a suitable ground point.
Only exemption is higher draw devices or low wattage LED's where 10a rated dual core is more than enough.

Hey Guys,

I appreciate your responses. I am still exploring what is on the trailer. I am more interested as to whether the trailer needs the dc or ac circuits earthed. I get it that the rcd on the house is different, but would expect an earthed trailer would feedback to the house if there were issues as there is an earth return in the line.

My norm is planes. We earth both AC and DC to the frame. Good practice. For my DC wiring I expect an earth somewhere for good practice and not a dedicated return. Likewise for the AC.

To note the enerdrive gear require the charger kits to be earthed. This was not done. The house RCD circuit tripped with nothing connected to the AC circuit in the trailer so am not happy. Will dig more during daylight hours tomorrow.

Thanks to all.

If the trailer has an AC inlet (as in there is fixed wiring) rather than just a fly-lead to a 12V charger then the chassis needs to be earthed and it needs to be wired in accordance with AS/NZS 3001 - "Electrical installations—Transportable structures and vehicles including their site supplies".

I'm only familiar with it as I've just replaced the vulcanised indian rubber and elastoplast insulated wiring in our 60 year old Baravan with something a bit more "modern and less likely to burn the thing to the ground and kill us all".

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Nothing quite like finding a double 10A GPO wired in 24/0.20 figure 8. At least the earth was 2.5mm.
My Grandfather was a master coachbuilder and carpenter, but not much of an electrician.

Just an update as to the progress on my wiring concerns. The RCD tripping at the house was due to a faulty external adaptor from the 15A trailer circuit to the house 10A circuit. Was a near new commercial device with RCD but was wired from manufacture with the Earth and Neutrals crossed. I didn’t buy it so was my first time trying to use. Go figure. Also found the AC earth just where the power enters the trailer.

Now that is resolved, am moving onto installing a disconnect switch at the batteries, a battery monitor with an earth shunt for the lithium batteries and a few bus bars to cut down on the number of leads on the battery terminals. If it looks pretty when done will share plus diagram.

Getting there and looking forward to happy camping.

General question, has anyone installed a 240VAC outlet to run their fridge when connected to shore power? Is it worth it?

My fridge is plugged into the 240v all the time and auto switches when shore power plugged in. I find it handy. Stops the charger dealing with the fridge cycling. I've only got a 10amp charger in mine. The fridge is the only really load on the system.

Originally Posted by eckolsim

Was a near new commercial device with RCD but was wired from manufacture with the Earth and Neutrals crossed.

Yowza! That's a very, very serious clanger.