Overview of 50-Amp RV Electrical Systems

It is important to have a full understanding of how different RV electrical systems operate, including the different outside electrical sources available at campgrounds. With the installation of more residential appliances, RV electrical systems need power to keep everything running smoothly. 50-amp power cords may be needed to meet the demand of RV electrical systems and all appliances inside the motor home, especially if 2 roof air conditioners are needed.

Today’s average roof air conditioner can draw up to 14 amps. Using two air conditioners and other electrical equipment requires more than a 30-amp system. 50-amp plugs have 4 terminals a ground, a neutral, and two hot legs on opposite of each other on the plug.

If the campground source does not have a 50-amp plug in, an adapter can be installed to the plug for 30-amp service. A 30-amp plug in will limit the amount of power you get inside your RV, almost cutting the flow of the current by half. A 30-amp plug will only have three terminals, a neutral, a ground, and one hot leg. It is always best to plug RV electrical systems with 50-amp power cords into 50-amp power sources; however, if only a 30-amp plug is available, you will have to manually limit the amount of electricity used in your RV. This means possibly not running one of the air conditioning units and connecting RV electrical systems through a 50-amp adapter to step down the system to a 30-amp service.

When at home you can plug RV electrical systems into a plug in the garage or outside of the home, however, you need to be careful not to overload your home’s power system. Typical residential outlets are only 15-amp and require adapters to reduce the plug. If plugging into a 15-amp outlet, you will need to understand your power requirements and probably only run the refrigerator. Many residential outlets are connected together or “ganged” to other outlets so other appliances such as a refrigerator, freezer, or air compressor may also be connected to that circuit. It is best to bring in a certified electrician to install a dedicated plug in your garage that is at least 20-amp to be used for your RV. Verify what appliances you will be running inside your RV and consult your electrician for the proper amperage.

Know the different types of plugs and adapters required to step down power sources to fit your RV’s needs. A good understanding of the 50-amp electrical service in your RV will help you avoid any problems when traveling down the road.

5 Responses to “Overview of 50-Amp RV Electrical Systems”

1. Jack Stackman September 23rd, 2016

   This is a poor description of RV service. One could be led to believe there is NOT 240 volts at the distribution panel. If there wasn’t, the neutral would be overloaded. Bottom line is, watching videos such as this is not going to make you knowledgeable enough to keep you and the coach safe.

   Reply

2. Alva Jim September 21st, 2016

   Will a 30A, 110V plug in service run a residential fridge, one A/C unit and a water heater?

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   • Customer Service October 4th, 2016

     Thanks for visiting the RV Repair Club site and the opportunity to assist with your 30 amp power draw question. It is possible to run those components on a single 30 amp circuit, however you need to know what each appliance draws and what else is drawing from the system. Newer AC units will draw up to 14 amps but not all of the time, just during peak temperatures. An electric water heater will draw approximately 12 amps, but only for the 10 minutes it’s heating water. A residential refrigerator will depend on the size and should have a sticker that states amp draw. Most common are 6.5 amps, however this is at start up of the compressor and will run much less when it settles into cooling mode. So you see that with everything starting and running at the same time, you could exceed the 30 amp capacity. However, another thing to keep in mind is your 12-volt converter will periodically draw 6-9 amps when charging the battery/s which will be required even when connected to shoreline power as your lights, vents, water pump, furnace fan, and even the refrigerator on 120-Volt AC all use 12-volt power. Then you have the TV, radio, microwave, you get the picture. You will need to understand the draw of each of your appliances and do some energy management. You might want to invest in an Energy Management System (EMS) from Intellitec which automatically shuts down appliances as the microwave kicks in, or AC units etc.

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3. Don Christiansen September 21st, 2016

   I don’t think this video has a clear explanation between the power difference between 30 amp and 50 amp services. For example, on a 50 amp service each hot leg is delivering 50 amps at 120 volts. That works out to 2x50x120 = 12,000 watts. On a 30 amp service there is one leg carrying 30 amps. That works out to 1×30 x120 = 3600 watts. Quite a difference.

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4. Tom Stalnaker September 21st, 2016

   “It is important to have a full understanding of how different RV electrical systems operate.” That is especially true if you are writing articles about electrical systems. This writer apparently does not. His statement that “A 30-amp plug in will limit the amount of power you get inside your RV, almost cutting the flow of the current by half.” is not correct. Since a 50 amp connection is effectively two 120 volt 50 amp supplies, dropping back to a 30 amp (120 volt) supply cuts to less than 1/3 of the power available in a 50 amp (240 volt) connection.

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