240V System
The orange 240v cable plugs into the on site socket then into the caravan socket which is usually situated in the battery box. The 240v then goes to a consumer unit.
The single switch on the right is the RCD, (residual current device), sometimes called a trip switch. With the trip switch in the up position the 240v system in the caravan will be live. The two other switches are MCB's (miniature circuit breaker). These are responsible for the circuits in the caravan. Typically, one will be 16 or 10 Amp and one will be 6 Amp. The 10/16 amp circuit will be responsible for the heaver equipment in the caravan such as the space heater, refrigerator and the socket near the kitchen area.
The smaller breaker will service the transformer and the rest of the sockets. There is a button which will test the operation of the RCD. This should be tested periodically to ensure the caravan is protected from a fault. If 240v is lost, this will be the first place to look. If the RCD is in the up position and stays there when the test button is pressed, then there is no 240v entering the caravan, the fault may be with the box on the site.
Power usage:
Care has to be taken to ensure the system is not overloaded due to the limited supply of amps. As a guide 2 KW, (average house hold kettle, ultra heat on full) is 8.3 amps (2000 w divided by 240v = 8.3 amps). Some caravan sites are still using 10 amp RCD's in the site box. This means that when the rest of the 240v system is taken into account, such as the refrigerator, transformer and the sockets an overload is quite frequent. Most sites are now converting to 16 amps as the modern caravan requires more energy to operate its systems. However, care has to be taken to insure that the Truma ultra heat is not on full when a kettle is used. The sudden draw on the system may trip the site box. As the site box is furthest away from the draw, it is most likely to be the box that trips, not the caravan RCD, (not 100% sure why this is, I'm not an electrician!). Any appliance over 2 KW is not recommended. Low wattage kettles are quite useful but may take a long time to boil. TV's and microwaves are low wattage, so are not a problem, that 5 bar electric awning heater may just be a bit to heavy!. The 240v system will also charge the battery when on site, most of the lights will run off 12v's from the battery. Test the battery is working properly by isolating the 240v (press the blue button) and insure the 12v lights still operate.