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Where Is The Circuit Breaker In My RV?

Where Is The Circuit Breaker In My RV?

It is wonderful to have an RV. You can travel anywhere without leaving your home. However, sometimes you will have to make small repairs. Thus, it is important to know about all the important parts of your RV. One of them is the circuit breaker. It plays a very important role in the whole electrical system of your vehicle.

If you have just bought an RV, you should not worry about finding the circuit breaker. Quite often, it looks like a panel, installed in a box. It can be covered with a plastic or metal door. Most of them are located near the floor or wall. They also can be under the bed or other furniture. Sometimes you can find it inside of exterior storage bays. Certain RVs have circuit breakers installed outside.

What is a Circuit Breaker?

A circuit breaker is an automatic switch that cuts off the passage of electrical current if certain conditions are met, such as voltage fluctuations. Unlike fuses, which are for single-use, an electrical circuit breaker or breaker can be reconnected as long as the causes that activated it has been resolved. When purchasing these components you have to take into account certain characteristics, such as:

  • work voltage
  • nominal current
  • breaking capacity
  • closing power
  • the number of poles.

The most used in domestic installations are generally thermomagnetic and differential.

Thermomagnetic Circuit Breakers

This device is in charge of cutting off the passage of current when it exceeds a certain threshold. Thermomagnetic (thermal) switches are used primarily to protect electrical cables and conductors against overloads and short circuits. In this way, they assume the protection of electrical means against excessive heating. Each of the circuits that are installed has its own thermomagnetic circuit breaker.

Thermomagnetic Circuit Breakers

They are designed to withstand the current peaks that are generated during the ignition of electric motors. Thermomagnetic (thermal) switches are used primarily to protect electrical cables and conductors against overloads and short circuits. In this way, they assume the protection of electrical means against excessive heating.

They are composed of two fundamental parts, as the word indicates: a magnetic part and a thermal part. The magnetic relay is the part in charge of short circuit protection and the thermal relay is the part of the circuit breaker in charge of overload protection. The Thermals open and cut the circuit when an intensity greater than the nominal one passes through them.

Differential Circuit Breakers

This device is responsible for protecting people from electric shocks. It works in conjunction with the earth connections of all installation elements. Compare the intensity that enters the circuits, with the one that leaves. If everything is correct, they should be the same and the switch remains closed, allowing electricity to pass through. If, for example, you came into contact with some part of the installation and suffered a shock, the output intensity would be lower, activating the switch that would cut the current.

This device protects us from the consequences that may arise from a current leak in our installation. It is called differential because it is capable of measuring the possible difference between the input current and the return current in an electrical system.

Although there are switches for different actuation intensities, high sensitivity differential switches are installed in domestic installations, which guarantees adequate protection for people. A wide range of automatic switches, with various control units and the possibility of communicating with programmable controllers.

Circuit Breaker Functions

In addition to reducing the space required for protection circuits, making the process of driving motors cheaper and more efficient, the component has several functions. Therefore, the device is able to provide more stable, safe, and reliable circuits.

Overload Protection

The component can interrupt the flow of current in case of overload, by means of a thermal trigger in its contact blades. This thermal protection works from two metal sheets, with different coefficients of expansion. When an overload occurs, the temperature rises causing these blades to deform, closing the circuit.

Short Circuit Protection

It works from a coil, which when energized with a current much higher than the rated current of the equipment creates a magnetic field that activates the switch and turns off the circuit.


It keeps the motor voltage separate and at the same time turns the equipment itself on and off, replacing a switch for connection and even a contactor.

Advantages of The Circuit Breaker

Some of the advantages are that the circuit breakers are reconnectable and do not require replacement items, such as fuses. They have a high breaking capacity, which means that they can be used even in places with a high level of short-circuit current. In some cases, the component does not require other protection circuits.

The circuit breaker guarantees total protection for the motor and the electrical circuit with its thermal and magnetic triggers. Auxiliary contacts can be connected to some models, if necessary.

Therefore, the circuit breaker is still capable of withstanding starting currents, that is, currents up to ten times the rated current without affecting its protection against adversity. The most important thing is to regulate the component according to the circuit in which it will be used.

Therefore, when installing a circuit breaker, you must adjust it to the motor rating. The circuit breaker allows the current to flow without interruption during the motor starting period, where higher currents are required.

Electricity in the RV: The On-Board Battery

In the mobile home, there are two separate batteries in general, unless you have an additional body battery for increased self-sufficiency on board. One battery for the chassis and a second for the living area. This means that if the (on-board) battery in the living area should be empty, the engine will still start thanks to the other battery.

What Works In The Motorhome Only With The On-Board Battery?

  • Light: The on-board battery is used here if there is no shore power available. You almost exclusively use LEDs in vehicles, so the light uses very little of the battery.
  • Toilet flush: This is also operated by the on-board battery. So there is no mishap.
  • Herd: It runs on gas, so it doesn’t need any electricity.
  • Heating: As long as you have gas onboard and your on-board battery is not empty, the heating in the motorhome works – even without shore power. Because the 12 V supply from the living area battery is enough to operate the gas heating.
  • Fridge: In most motorhomes, the refrigerator runs on gas and is switched to electricity as soon as the vehicle is connected to an external power source. However, modern refrigerators always need electricity, even if they run on gas. However, this current can also be taken from the on-board battery.

Small automatic switches (PIA)

The circuit breakers serve to protect installation (the cables) from an overcurrent (overload) or short circuit. There will be as many PIAs as there are different circuits inside the vehicle.

Normally for RV, the cable should have a section of 2.5 mm and therefore it should have the protection of 16 Amps, which depending on the caliber of these, will fire sooner or later. The circuit breakers are available in different nominal currents (10, 16, 20, 25, 40, and 63 A).

Depending on the caliber of the circuit breakers, the trip at a different intensity, so the cable to be installed must be:

  • 10 Amps: Protects cable with a section of 1.5 mm² (Lighting)
  • 16 Amps: Protects cable with 2.5 mm² section (Power outlets)
  • 20 Amps: Protects cable with a section of 4 mm² (Kitchen appliances)
  • 25 Amps: Protects cable with 6 mm² sections (Oven and glass-ceramic)


What to Do In Case the Circuit Breaker Tripped?

Sometimes you may find yourself in the RV doing daily tasks and suddenly the power goes out. You simply go to check the mainboard, where you find that the circuit is down. After uploading it, you wait only seconds and the same thing is repeated, again the circuit breaker trips and the light goes out.

This happens because circuit breakers are designed to “jump” and cut off the power supply when some kind of fault or malfunction occurs in the electrical circuit. To solve the issue it is always better to call the specialist. Nevertheless, there are alternative solutions.

Alternative solutions

As another alternative, if you do not contact a professional electrician, what you can do is go to the mainboard to disable the thermals and differentials corresponding to the circuit. Then disconnect all the electrical appliances and enable the thermals and differentials again. Reconnect the electrical appliances one by one, verifying which appliances would be conducting a ground leakage.

In the event of detecting that an appliance has a ground leakage, do not reconnect it and take it to the corresponding technician so that they can check it and leave it in optimal condition.

Other Causes of Tripping Circuit Breakers

Short Circuit: Some indicators that this fault may be happening are:

  • Cables are damaged or melted.
  • Outlets and plugs have a burning smell or have dark stains.
  • Cracked wire insulation.

In this case, if you are going to check the aforementioned on your own, first confirm that the power is turned off in the socket where the device is connected. If you detect any of these situations then contact an electrician, as a power failure of this type is not something that should be left unresolved.

A ground fault is a type of short circuit. A quick way to detect it is by using a device called a Grounding Tester. This device is plugged into the outlet, and once connected the button is pressed. If the circuit breaker trips when pressed, then it means that the electrical circuit is working well.

If nothing happens when pressing the button then it means that there is a ground fault in the circuit. In this case, you again should contact an electrician to solve it. The good thing about a grounding tester is that it is not an expensive device, it is simple to use and it can prevent future electrical accidents.

How To Connect RV To The External Power Source?

If you want to connect your RV at parking spaces and camping areas you will need cables. It is one power cable that is long enough or you can have a cable drum. Most of these wires are adaptable to match various charging situations. Thus, they have CEE adapters. You simply use them into the outside socket of the RV.

Most models of RV and trailers have power sockets outside of the vehicle. You may have difficulties to find it in the beginning as it can be hidden under a cover at the sidewall, bottom of the floor, and the rear. They can be already connected via CEE connection sockets through 230V power supply cables.

It may happen that your default cable is rather short. You should check it before going on a long trip. Thus, you will be able to prepare by getting an additional cable drum to serve as an extension cable. It greatly solves the time when you park near power sources.

How to Install the Ground Connection in a Camper Van?

The way to install the ground connection in a home vehicle is as follows:

  • From the external charging socket, take a cable to the general protection panel.
  • From the general protection panel, start with another cable to each plug, inverter, battery charger, boiler, or any electrical element installed in the vehicle that has a terminal for grounding. Also, connect another wire to any screw on the vehicle’s chassis.
  • Join all the cables in a junction strip in the general protection panel.
  • The color of the ground wire has to be yellow/green, and the cross-section has to be equal to or greater than the current wires.