Wanderer Motorhome Page 12

1. Contents:

1. RCD Typical fitting 2. The Plug in Tester  3.  The Electrical Trip  4. Reverse Voltages Continental Sites. 
5.  Reverse Plug Drawing

        The RCD unit is designed to give both overload and earth leakage protection for the electrical supply in the Motorhome. The RCD is usually tested by pressing the test button. The main switch them drops out. If a fault is still present you will not be able turn the main switch back on. This test button must be checked periodically, with the main switch turned to the on position and live mains connected.

        The Miniature Circuit Breakers, inside the RCD box container, are really mechanical fuses which will cut out during an overload or short circuit.

         This will turn the mains supply off automatically, isolating the mains supply from the Motorhome. The MCD’s, which replaces the wire fuses, are a much more convenient switch device, where you might not have a fuse available.

          The RCD is useful as a control switch for the whole Motorhome, as this is the first in line, from the caravan site input to the van, to the Motorhome for all the electrical appliances.

          The RCD is a balanced device which depends on a good earth, when 'Misbalanced' by a resistance to earth, this can be a hand touching a live terminal. This switch will trip out at the usual current of 30Milliamps. Research elsewhere has shown that 30Milliamps is safe for the human body.

          On one site in Spain no earth was indicated on our test plug. This meant if we had an electrical fault the RCD would not have tripped out.

          See the drawing and picture below for a typical installation, this is in our Motorhome. A not very convenient position, when the wardrobe is full of clothes!

I must take up the issue of the Mains earth and the plug tester, as I feel this could cause confusion and worry to others.

The phrase 'Connection to earth is made via the tyres.' Not true, I emphasise this is not true. All Motorhomes can be considered as an electrical device connected to the mains, as for example an Electric Fire at home. The electric fire has three wires connected, Live, Neutral, and earth. The earth is connected to the metal frame. Any faults and the electric is taken back to the mains via the earth wire. The manufacturer ensures this wire is attached to the frame very securely.

It's the same with the Motorhome any appliance fault and the electric is taken back to the mains power station via the earth cable through camp site supply. Hopefully before then the Motorhome Mains on/off switch will have tripped.

The slight difference, but important, with the Motorhome to an electric fire is; a cable is connected, as an added earth wire, from the earth of the Motorhome electrics, and is attached to the vehicle chassis, plus any metal wall covering.

This should be considered during Habitation checks. Somewhere on the habitation check sheet this attached cable should be checked and ticked off. How many Motorhome owners know where this earth cable is attached to the chassis?

 Regarding the 3pin plug tester. This device checks three cables only, the Live, Neutral, and earth from the mains input. And ensures the electric socket is correct back the mains or camp site supply.

It does not check or is meant to cover any fault to a camp site field earth via tyres! Just as one would not check any fault to a kitchen floor when you plug in the electric fire at home. What is important is the earth cable previously mentioned, is it attached to the vehicle chassis?  

In my case recently  I checked the earth cable to chassis and found it had fallen off due to corrosion and deterioration in metals caused by oxidation or chemical action, for how long I wondered! The 3 pin tester showed the earth was correct. It is this earth wire which is never given prominence in Motorhome literature.

 If anyone feels he has an earth problem then he should be looking at this cable to ensure it is attached to the chassis. Also the coach builder will have connected a cable to the Motorhome metal walls somewhere.

Incidentally the earth wire attached to the chassis should have a metal label displayed, as seen in most homes these days, 'Safety Electrical Connection, do Not Remove'

During a visit to a Spanish camp site my plug tester showed no earth. I attached an earth wire from the vehicle chassis to a tent peg, but, as expected, the plug tester still showed an earth fault!

 

The main problem after coupling the electric cable and checking the voltage inside your Motorhome,  is then  finding the voltage reversed,  then the irritation of having to re-couple different wiring arrangements at the Voltage source. i.e. Caravan site electrical supply post. On a dark or wet night this is not very convenient, in fact dangerous. It has always surprised me the nonchalance of the camping fraternity when it comes to mains electric.

In the Motorhome Magaziness they advocate having alternative plugs and sockets to overcome this problem!

In my previous Motorhome I used a two socket arrangement, where one was reverse voltage fitted.

 I discovered at many camp sites,  at the source post, you could turn the 2 pin continental plug around 180 degrees, which then reversed the voltage,  and obtain correct voltage to the van.

While this was convenient on most sites, there is always the awkward one. The one where it was not possible to turn the plug around. On some sites the owner will plug in for you and lock the source cabinet door, either for safety or to ensure those who don't pay cannot get in! This one occasion I discovered the voltage was reversed, and of course the owner had disappeared.

While perusing the DIY shelves in Continental supermarkets, It came to me, why not use the one continental plug and socket, and turn around the plug INSIDE the Motorhome! and reduce the complexity of my previous cable arrangements.

The mains input cable, from the wall of the van, is usually fitted to an RCD for protection of the electric’s.

My modification is to attach a new cable from the input plug on the Motorhome wall, and fit it to a continental socket.

The mains cable which originally came from the wall input to the RCD,  was removed from the wall plug, and now has a 2 pin continental plug attached.  This plug is inserted into the socket, from the wall input.

When we come across a reversed mains supply. I don’t need to go back outside, I just pull the RCD input plug out and turn it around.

So instead of carrying alternatives for reverse voltage. I now carry just a single 2pin continental plug with blue socket 16 Amp adaptor attached.

No other adaptors are required as any reverse voltage is taken care of with my modification inside the van locker!

I have enclosed a drawing below of my modification which makes it easier to understand. The modification should be checked for correct phase of the wiring before leaving this country. This basically is checking which way around the continental plug is inserted for correct phase of the wiring.  This is where the test plug is used, three lamps alight then all is OK.

In our travels through France, Spain, and Portugal this year [2003], I have only needed to use the one continental two pin plug and 16Amp socket adaptor.  [ The one with an indent in its outer rim for earth.] This arrangement has proved to be very convenient.

As continental sockets have no markings for correct wiring, I have taken to fitting sockets with the earth cable close to the neutral and the live wire in the opposite side of the socket. 

I've also included my method of connecting wires to the Continental plug. You can see I have adopted the British method of fixing the wires, Brown on the right and the Blue on the left.

See below:

Below can be seen my method of changing a reversed voltage on Continental Sites:

WARNING

It must be said: