RV electrical systems are quite a bit more complicated than your typical household systems because an RV has low voltage, high voltage, and vehicular electrical systems as well as storage and consumption issues. In addition to this mix there is also the constraint that electricity is hard to come by, especially in large volume, out in the boonies.
Smaller RV's will usually be configured for 30 amp 110 volt service while larger RV's will be configured for 50 amp 220 volt service. The 30 amp service provides about two standard household circuits and the 50 amp service provides about six. The wiring for this 'high voltage' service is very similar to that used in standard home construction. You can find wire, circuit breakers, connection boxes, and outlets at any electrical supply outlet.
Note that most households use a 100 or 200 amp 220 volt service. 220 volt service is essentially two 110 volt services wired in series to add voltages. 110 volt service is really about 117 volts but may vary from about 110 to 125 and still be considered within specification. This means the 220 volt service is nominally 234 volts and may vary from 220 to 250 volts.
Since the 30 amp service is 110 volts, it can be plugged into just about any standard electric outlet. It can also be plugged into one 'side' of a 50 amp service. But, unless the plug is rated for 30 amps and is on a circuit designed for this load, the current will be limited to what the circuit on the plug is allowed to deliver. The limitation is usually in the fuse box with a fuse or circuit breaker designed to turn off the circuit if too much load is attached.
You can also plug 50 amp service into standard electric outlets but are again into the limitations of the circuit providing the service. 220 volt systems are essentially two 110 volt services in series. You can arrange wires to attach 110 volts to each of those systems separately if necessary.
You must check codes and regulations prior to messing with high voltage systems! Make sure you don't do anything you are not supposed to do. Instruction and code books can be found in electrical supplies retail outlets.
There is often a need for basic systems when the power grid is not available. RV's use a low voltage system drawing power from a typical automotive type battery for these systems. This 12 volt wiring provides for lights, water pumps, furnace blowers, and ventilation fans. Most of these devices consume from five to ten amps or under a hundred watts or so.
The wiring, fuses, and other infrastructure for low voltage RV systems use automotive parts and techniques.
When on the road your RV needs to meet all vehicle codes for signaling, brakes, and other matters. There is also the need to provide power to the RV house battery that supplies the RV low voltage system.
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Basic guides to understanding the technologies with practical hints and tips for a more successful and satisfactory outing.
Note: there are a lot of facts, assumptions, and calculations that are used to provide the information presented here. The intent is to provide 'back of the envelope' accuracy and not engineering or science level accuracy. There may also be cases of teaching license taken, such as the water and electricity analogy. However, errors or miscalculations may lead to misinformation or some analogies may mislead. If you see something you think should be corrected, please let us know - email rvtech@SierraNevadaAirstreams.org