It is of critical importance that the inverter in an RV be correctly grounded to prevent the risk of electrocution of the inhabitants. The RV system may be an off-grid system or have the option of connecting to shore power (grid-tied), and it is important to note that both scenarios present the risk of fatal electrocution.
The inverter grounding wire to the grounding point must be of the same gauge or thicker than the battery wire. The grounding wire must be securely connected to the RV chassis using a bolt-on connection. Always follow the instruction of the inverter manufacturer on how to ground the inverter.
RV Inverters must be correctly and securely grounded to the chassis for the following reasons:
- Protecting the RV appliances from power surges;
- Grounding directs power to the AC appliances by reducing the potential of reverse current;
- Grounding stabilizes the inverter output voltage;
- Prevents the inhabitants of the RV from injury, fire, or electrocution.
Let’s review the electrical systems in an RV and discuss how to ground the RV inverter properly.
Does An RV Need To Be Grounded?
An RV does need to be grounded in some way. Failing to ground an RV will cause a condition known as ‘hot skin.’ This means that in the event of a short circuit in the RV, the metallic skin of the RV will become charged.
If someone touches the RV, they will complete the circuit between the RV skin through the person’s body to the ground. The current flowing can be sufficient to cause a fatal shock.
Grounding an RV can be achieved in several ways. The electrical outlets at campsites are already grounded inside the plug you use for the electrical hookup.
Make sure that the electrical connection point provided by the campsite is in good working order by testing it using a multi-meter.
RV campers can be hard on the electrical outlets and often force their plugs into the electrical connection point, causing the ground pin to break off, resulting in defective protection.
Off-grid power systems using an inverter must have a grounding wire installed from the inverter to the RV chassis.
Carefully follow the inverter installation manual and ensure that the grounding wire is of sufficient gauge and securely connected.
RV Electrical Systems And Their Grounding
An RV has three distinct electrical systems to power the vehicle and the coach accommodation space. The vehicle has a 12V automotive system used to power the starter motor and charges the 12V lead-acid battery and other DC loads relating to the vehicle.
The RV coach typically has a 12V DC system to power small DC loads and a 120V AC system to power the AC appliances in the coach.
The 120V AC can be provided via a power inverter that draws DC from house batteries and converts it to alternating current (AC) to power the appliances running on AC power.
See also: Solar Panels for RV Installation: A Comprehensive Guide for Beginners
Shore Power Connection
Most RVs are also fitted with a shore power connection point to plug the RV into grid-powered connection outlets available at most camping grounds and trailer parks. The RV AC systems are 30A or 50A systems.
Commercially sold RVs are fitted with a circuit breaker connection to prevent overloading the electrical system and causing damage to the components and appliances of the RV.
For true off-grid-camping, solar power generation to charge the house bank battery or a portable fuel-powered generator is possible.
Whether you are off-grid or grid-tied, the potential of electrical shocks and overloads necessitate the proper grounding of the coach electrical system.
Steps To Grounding an Inverter To An RV
- The inverter must be installed in a location that is close to the coach battery bank and the shore power connection point.
- The installation point must be cool and dry and have sufficient ventilation to allow for sufficient inverter cooling.
- The inverter must also allow for easy access to monitor or service the inverter and should have a visual display inside the coach displaying the battery state of charge and power draw on the inverter plus any error messages or alarm lights.
- The inverter must be securely fastened to prevent it from coming loose during travel. Ensure that there is some redundancy in your method of fastening. If one bolt breaks, another should hold.
- The wire gauge of the battery connection cables must be thick enough to comfortably cope with the current drawn from the batteries to the inverter.
- The positive terminal of the inverter must be connected to the positive terminal on the battery bank, and the negative terminal on the inverter must be connected to the negative terminal on the battery.
- A grounding wire with the same wire gauge as the battery connection cables must be securely connected to the RV chassis via a bolt-on connection.
- The grounding wire must be securely connected to the inverter grounding connection point.
All the components of your RV power system will require a single common grounding point on the chassis of the RV. The solar panel, battery bank, and inverter need to be connected to this single grounding point.
Check that the grounding wire connections and the battery cable connections are secure and will not rattle loose during travel.
RV Inverter Installation Advice
If you do not have experience with electricity, get a qualified electrical technician to help you with the installation. Incorrectly installed components and wiring can lead to costly failures and potentially cause a high risk of fire or electrocution.
Watch some installation videos on YouTube to help you decide on the size of the inverter and battery bank and where to install it. Get some advice from other RV owners or electrical system installers before buying any hardware.
If you feel capable of doing the inverter installation and wiring to the RV coach electrical distribution panel yourself, read the inverter manufacturer installation guide well.
Plan Battery/Inverter/Ground Connections
Draw out your wiring plan and determine the right size copper gauge wire to connect the battery to the inverter and ground the inverter to the RV metal chassis.
Do not wire your RV to have shore power and inverter power feeding the AC power outlets in the RV simultaneously, leading to a disastrous outcome. Do not run your inverter and DC to DC converter simultaneously, which will drain the battery bank very fast.
The shore power connection on your RV will be wired to connect to the grounding of the campground electrical pylon. Do not assume that the campground electrical system is faultless.
Test the voltage at the tower using a multi-meter before connecting your RV shore power cable.
References:
