During last winter’s stay in Spain, more than once, in the early morning, I experienced the outside power bollard tripping. Fortunately, the switch box is unlocked so it was an easy matter to turn off some appliances, then go out and switch the power on again. Eventually, I realized that it was my microwave oven which was drawing much more current than I realized. After all, it’s only a 700-watt model, so theoretically (in Spain) it should draw approximately 3amps. In actual fact, its draw is almost 6amps. That together with the fire on the 1000W setting, plus the fridge, plus (maybe) the water heater and maybe the battery charging, it should have coped. However, it didn’t. When I returned home I decided to fit a voltmeter. They are available from both Amazon and eBay. Links go out of date quickly so I’ve removed them. Simply put into the search box of either company “Voltmeter/Ammeter/Power meter and several different models will come up. Just be sure that you order one which will cope with mains voltage – some are only for 12 volts.

The wiring in the caravan needs to be modified so that the mains positive wire passes through the coil. It won’t work by putting the complete cable through the coil since one lead will cancel out the other. On my caravan, the main supply comes in at the socket in the battery box. It then crosses the caravan and up into the overhead locker where it plugs into the back of the supply unit. To modify the wiring, I unplugged the main cable and removed the IEC plug. I made up a new section of wiring with a loop in the positive supply passing through the coil of the meter. To this new section, I refitted the plug and connected the other ends to the main cable ends which were previously connected to the plug.

The wiring diagram is shown on the back of the meter.

In my caravan, I’ve removed the old radio since I never use it. I made a new facia using Fablon over a piece of plastic and the meter is mounted in that with the coil and extra wiring sitting in the space previously occupied by the radio.