Fit a Smart Meter to your Caravan

Now, WHY would you want to do this?

In the UK, I mainly use CL campsites. In France, I mainly use “Municipal” (local council) or I use “Cheap” sites – I don’t need “fancy” facilities – I have a “Fancy Caravan”!

The problem is that whilst 16A Electric may be normal on UK Caravan Club sites and “up market” Commercial Sites – its not unusual to find sites that offer less than this…

In France this year my supply varied from between 6A and 16A. If you use the simple formula: 1 A = 250W, this means that 6A would offer me 1500W (plus about 15% more on “overload” for a few minutes).

3A = 750W, 6A = 1500W, 8A = 2000W, 10A = 2500W, 16A = 4000W

Now the Fridge takes about 120W, the 2nd Fridge in the back of my car was taking around another 150W, the Hot Water system takes around 800W, the 12V system takes whatever Watts you are drawing – extractor fan, lights, radio etc… it mounts up. Then the Electric Kettle takes around 2000W….

2000W???? How can I run this along with everything else on a 6A supply?

Answer – you Can’t! – Get a “low power camping kettle” – 750W or use the gas!

So, the first thing I do when I arrive at a site is try to find out how much power is available: Ask? Look at the post? Open the box on the post (if you can?), or Draw power until it blows, ask the site to reset it and ask how much power you can have?

I don’t recommend the last option unless you can open the box and reset it yourself (you would be surprised how many French and Spanish sites this applies to!!!)

I fitted a “Smart Meter” so that I could monitor my incoming power at all times. (It varies as the hot water cycles, fridge cycles etc.)

Once you know the maximum watts available, it’s just a case of keeping en eye on the meter to ensure you don’t exceed it (for long!).

Be aware the the 1A = 250W is the “Input” power – This is usually marked on the appliance somewhere. Beware with a Microwave oven – if it says 800W on the front – that means it is likely to draw around 1300W INPUT!!!! Check the plate on the back or trust me!

I bought my “Smart Meter” from Ebay. Try searching for “Smart Meter”, “Energy Monitor”, “Owl” or “Onzo”. I paid around £10 for my meter, new, but old stock with leaking batteries – just fit standard AA cells. This was about 18 months ago, they seem to be more expensive now.

Also MAKE SURE it is complete! – Not only do you need the “Remote Display”- but you MUST have a “Sensor” that fits over your incoming Electric cable (LIVE line only – see later – it’s not THAT simple to fit!).

Assuming you have a kit, try it on your home electric meter to see that it works – clip the sensor over your LIVE wire from your Meter to your Fusebox.

Then the fun starts:

You need to separate out your LIVE cable inside your caravan between where it comes into the Van and where it goes to your “Fusebox”. However, you cannot just “expose” the live wire – this is against Regulations and is Dangerous! All 240v Cables MUST be double insulated by UK regs (BS7671).

Cut open the incoming cable to expose the inner cores. Extract and cut the LIVE wire only. Fit a junction box over the joint, split out the LIVE cable into another “double insulated” cable and loop it back. Then you can fit your “Sensor” over this loop.

Cut a length of suitable cable for the loop.
Live wire split, looped out and back. I used “Wago” connectors (Screwfix), but you could use Chocolate block terminals
Final job with showing the loop and the “Sensor” fitted over the loop.
The Onzo display unit can either run on batteries or a USB supply. I have replaced all of my Caravan 13A sockets by ones with USB supplies built in.

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