What size wire for a 50 amp RV plug?

In this article, we will answer the following question: What size wire for a 50 amp RV plug? We will discuss keeping your RV connected to a source of energy and the options you have for 220V. 

What size wire for a 50 amp RV plug?

The size of the wire for a 50 amp RV service should be size 4 AWG. Cables are rated by voltages as well as the wattage for which they are to be used. A wire with a larger diameter can carry more current than a smaller one. Using the wrong size cord can cause the cord to overheat and burn out.

  • 50 Amp Aluminum Cable

Aluminium wires are classified differently from copper cables. For 50 amp aluminium wire use # 4 AWG. The smaller the number of the wire, the larger the diameter of the wire. For example No. 4 is larger in size than No. 6. Aluminium wires come in different types. The THWN and RHW types are the most commonly used. The No. 6 is good only up to 40 amps.

  • 50 amp copper wire

For a No. 6 or No. 8 copper wire, THWN can be used. No. 6 copper wire can withstand up to 55 amps at a temperature of 60 degrees Celsius (140 degrees Fahrenheit). No. 6 is highly recommended but it is best to use a larger wire.

  • Voltage drop

When calculating a circuit, pay special attention to the cable voltage drop. The voltage drop is generally caused by the resistance of the wire. The smaller the size of the wire, the greater the resistance. When selecting a cable size, if the run is more than 100 feet (3048 cm), choose a larger measurement.

How is energy generated for the RV?

Most RVs have two batteries. The engine (for starting) and an auxiliary battery (for the passenger compartment). Although it is increasingly common to equip the motorhome with a third additional battery.

The auxiliary battery generates 12v for the lights, taps, television, USB connections, but it does not generate 220v so the plugs do not work with the power of the auxiliary battery.

If we want 220v plugs to work (and use many of the appliances we use at home such as a dryer, juicer, blender, etc.), there are different alternatives:

  1. Connect the motorhome to the electrical network of a campsite or service area using the typical electrical connector cable.
  1. Install a 12v to 220v power inverter. The inverter is generally used for not very long uses, although it all depends on the power of the accessories we want to use and the inverter itself (150W, 1000W …).
  1. Use a gasoline generator. Very popular for prolonged uses.

Returning to the batteries, one of the most frequently asked questions is to know how long the auxiliary battery, of the “house”, lasts. The theoretical answer is simple: it is a mathematical formula, it charges less discharge, that is, if the consumption (of lights, television, taps) is higher than the charge, we will end up using the battery.

How long does the auxiliary battery charge?

Most of the RVs of the rental companies come equipped with the most basic accessories so consumption is low. In addition, taking into account that they are usually equipped with solar panels (or solar panels) and that having the engine started they charge both batteries, they are practically never without a charge. Solar panels are an ecological and easy way to generate more energy during your trip.

With regard to individuals, practically everyone today equips their RVs with solar panels on the roof to gain autonomy and use the devices for longer. In this way, the batteries are charging regardless of being connected by cable and without having the engine started.

Gasoline generator for RVs

They are small gasoline engines that, thanks to the alternator, generate a current close to 220v. That is, the current necessary to be able to use the plugs in the motorhome.

There are them with different powers, making it possible to turn on the lights, use the microwave, refrigerator and watch television at the same time.

The most negative thing about electric generators is that the noise can be a bit annoying. Therefore, you should make sure to buy one that does not produce little sound. Those that generate 60db or less are the most suitable.

What options are there to have 220v in an RV?

Another simple and inexpensive way to have 220V power in our motorhome or camper is the power inverter.

They are especially useful not only because they do not require any type of installation, but also because they usually include a USB input in addition to the 220V input. For them to work we will only have to connect them to a 12V socket or “cigarette lighter” that goes to an auxiliary battery. 

We can also plug it into the engine battery, but it must be on. The only downside of the inverters is that they will continue to consume battery and we will not have “unlimited” electricity as with power cables.

Another method that can be very useful is the solar panel. Although they do require installation, the truth is that it is quite easy to attach it to our vehicle, so if you feel capable you can do it yourself. 

If you have doubts, you can always consult a professional. Installing solar panels is an ecological, economical and reliable solution, and it will also give us autonomy and independence that we could not achieve otherwise. Most solar panels are universal and adapt to any type of motorhome, so you will not have compatibility problems either.

The last option is gasoline generators. A useful option if we want to charge high-performance equipment without wasting batteries or depending on any type of cable. Their downside is that they are somewhat noisy and can give off a certain smell of fuel. 

Gasoline generators can be mobile or they can be installed in the lower part of our motorhome. This last option is the most recommended as it will partially isolate us from noise and odours.

The bottom line

Now you already know how electricity works in an RV, in addition, you know alternatives to increase energy production. 

We wrote in another article about how to increase the autonomy of your RV. Make sure you check it out and let us know if you have any tips or suggestions on the content. 

FAQ on What size wire for a 50 amp RV plug?

How does the electrical system of an RV work?

The sockets that are used on a day-to-day basis are generally 220v and the RV only generates 12v. This means that during the trip, with a fully charged battery, you will probably have 2 hours with the lights on and 2 hours with the television. At the end of this time, the battery will run out

How do you recharge the battery of a motorhome? Is it necessary to plug it into 220v? 

The batteries are recharged automatically thanks to the energy generated by the motor. … Another way to charge the battery, although in this case it only affects the auxiliary, is by connecting the motorhome to 220V power.

How many solar panels are needed for a motorhome?

So with approximately 2 solar panels of 150W, it would be enough, but what about winter? In winter we have less sun, so we tend to calculate it, for security more or less in half and each plate would give us about 250W, so you would need 4 plates of 150W

How long does it take to charge a motorhome battery?

So the charging time for a 100Ah battery is 12 to 16 hours minimum and if we have two batteries, double it. If you want to recharge faster, you must install a special 20 A electronic charger.

What is a motorhome booster?

Boosters are devices that give us a large load intensity for our passenger compartment batteries regardless of all the factors that I have previously mentioned (25 or 40 amps), so that in a short time and a few kilometres we fully recharge our batteries.

How does a camper work?

The camper has a 200 amp auxiliary battery that can be recharged in the following ways: By starting the vehicle’s engine. Through the charging cable, in conventional sockets (campsites, motorhome areas, etc.). 


What was missing from this post which could have made it better?

Leave a Comment