The information in this article applies to all brands of recreational vehicles.
AC power is not dependable in motorhomes, trailers, 5th wheels, and travel trailers. One day the power will work fine and the next it will not work. What to do?
Common RV electrical problems
(1) A loose connection can be easy to detect.
If the appliances are plugged into a surge protector or power bar, the problem is simply a loose connection. Power bars should be used when there are multiple AC wall receptacles in one location such as over kitchen cabinets or entertainment centers.
When power is disconnected from the motorhome, there will be a small spark at the loose connection. The spark may be inside a wall receptacle on the inside of the wall. The best way to prevent loose connections is to tape over each unused hole in the power strip with electrical tape. If you are not familiar with electrical problems, then hire a licensed professional to inspect your AC system.
(2) A loose wire
This can be as simple as a black wire touching another black wire inside an electrical box or between electrical boxes. It can also be as significant as two wires shorting out and causing a fire.
(3) An open wire
This can be caused by a broken wire, corrosion, or rust. Wires can break if they touch each other as they are installed, if the motorhome chassis is distorted by hitting something, and from normal wear and tear.
Excessive vibration from rough roads or other causes can cause open wires. If you have an electrical problem at home with AC power after you have had the motorhome for only a short time, it may be caused by worn insulation on the AC power wires. This is more likely to occur when you are not using your RV during cold weather months.
(4) Fuses and circuit breakers
both protect the wiring but work differently. Fuses and fusible links are designed to only allow limited electrical current to pass through because a wire burned off and created an open circuit.
Both fuses and circuit breakers use a heat-sensitive device to detect an overload condition, but they differ in the way they stop the circuit from working when too much electricity flows through it. A potential danger with using a fuse is that if it turns out, you will have no power unless you replace that fuse or find the cause of the problem such as an open wire or shorted wire.
(5) Overloading an AC circuit
This can be the result of using too many appliances on a circuit or connecting two different sized wires to the same wall receptacle.
For example, you could overload the 15A circuit in a motorhome if you put a 10A 1200 watt microwave oven on it or connected a 15A light fixture to a 20A AC power wire. Never use 14 gauge wire to connect to an electrical box designed for 12 gauge wire. A wire that is undersized will overheat and potentially start a fire.
For example, a loose wire (such as a wire connected to an electrical box or a light fixture) can rub against something and start arcing. A loose screw can touch the inside of the electrical box and cause arcing.
Arcing can also be caused by pieces of plastic or metal getting into the power wires such as after installing new appliances or when touching something with wet hands.
The most common cause of arcing is if two wires are touching each other on the outside of an electrical box or on the motorhome chassis. Arcs are more likely to occur when there is excessive vibration from rough roads or wind in your roof top air conditioner.
(7) Sometimes the wires will not be touching each other but they can still cause a fire.
If wires are in contact with each other for any length of time, they can develop a power flow path which is called a high resistance. A high resistance means that too much electricity flows through the wire and it overheats and possibly starts a fire.
To prevent high resistance, do not allow wires to touch each other for long periods of time. Shielding is another way to prevent high resistance; it prevents the electricity from flowing in certain directions such as from motorhome chassis to electrical box. Shielding is commonly used in solar panels and wind generators.
(8) Wiring should be properly sized for the application.
Use 10 gauge wire for 10A circuits, 12 gauge wire for 15 or 20A circuits, 14 gauge wire for 30A circuits, and 16 gauge wire for 50A circuits. Always use the proper size wire to handle a specific amount of electrical current (amps). If you use too much current, a fire will start or the wiring may overheat and burn off. If you use too little current, an appliance will not work correctly or it may not work at all.
Moisture can cause corrosion on metal wires and metal connectors. It can also corrode connections between wires and connectors. Water getting inside a wall box from rain or sprinklers can cause corrosion inside the box. Electrical tape has some insulating properties but it will not protect from corrosion in areas where water gets into the wall box or motorhome chassis. If you see rust on electrical connections, it is because water has gotten inside. For example, if you see rust on an electrical connection to a battery terminal or an alternator, it is because of water getting inside the connection at some time and then being drained off.
(10) Moisture can also cause loose wires
inside a junction box or wall box. If wires are not securely fastened to the sides of the box and other supporting wire clips, they can move around until they touch something else which turns them into a high resistance path that generates heat.
This will overheat the wire and cause overheating which could start a fire. It will also make the wiring in the box inefficient because too much power flows through it. Damaged wires inside a junction box can be a fire hazard and are usually quite costly to fix.
(11) If you have too much power flowing through a wire or junction box
thermal insulation will get very hot and this can cause overheating which is a fire hazard. You need to do some math to determine how much power is flowing through a wire and junction box so you do not overload it. For example, if a lamp pulls 30 watts of power, it is drawing 3 amps. If you have too much power flowing through a wire or junction box, thermal insulation will get very hot and this can cause overheating which is a fire hazard. You need to do some math to determine how much power is flowing through a wire and junction box so you do not overload it. For example, if a lamp pulls 30 watts of power, it is drawing 3 amps.
(12) Thermal insulation
will break down in time because of sunlight and heat cycles as well as other things like vibrations caused by road bumps. This can lead to wires touching which cause short circuits and fire hazards. You will have to re-insulate the wires when this happens.
If you do not want to use thermal insulation because it is an extra cost in materials and labor, you can use some sort of clamps or cable ties to help hold the wire in place.
But be careful that these are not sticking through a hole in the junction box cover and making contact with any hot parts inside the box. If you do not want to use thermal insulation because it is an extra cost in materials and labor, you can use some sort of clamps or cable ties to help hold the wire in place.
How do you troubleshoot an RV electrical problem?
The first thing you need to do is find a wire that has a high resistance. When there is a high resistance, your battery will discharge faster because of the current flow through this wire.
You should also use a voltmeter to check the voltage at the wire with the high resistance. A voltmeter can be used to test for loose or corroded electrical connections, loose wires, wires touching each other inside an electrical junction box or motorhome chassis, wiring that has a missing insulation coating and for overheating wires which are often found in RV junction boxes. The voltage will be high if there is a short circuit.
The high resistance will be the cause of the short circuit.
How does electricity work in an RV?
There are three main sources of electricity in an RV. An inverter converts the DC power coming from a battery into AC power which can be used to recharge the RV’s batteries and to make electricity for things like microwave ovens, TV, and lights.
A generator provides DC power but it is usually used to make 120 volt AC power. If you have 120 volt AC power coming into your motorhome from shore power when you are plugged in at an RV park, then there is no reason to run a generator.
The third source of electricity is solar panels which make DC power but cannot make 120 volt AC unless you also use an Inverter or Generator. Solar panels are usually used to charge a battery bank but they can be used to power small devices such as a laptop computer or cell phone.
Each of these sources of electricity will have different loads on the system which means that some parts will get hot. For example, the batteries, inverter, and solar panels all get hot because they are making electricity. The motorhome chassis can also get warm if it is doing work such as starting an air conditioner compressor or a refrigerator compressor. The electrical panel inside the RV can also get warm if it has too much current drawn through it.’