what size wire for 50 amp rv service

What Size Of The Wire For A 50 Amp RV Service Do You Need To DIY?

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Guess what, making plugs work in your RV does not require pro-electrician skills. What size wire for 50 amp RV service? Questions like this sound too technical for RV owners, right? In this post, we are going to tackle almost everything you need to know about the RV electrical system. 

An RV is for those who are finding relaxation away from the hustle and bustle of the city. These outdoor activities are supposed to be stress-free. Your RV should be your vacation buddy, not something that will add up to your piled up stressors, especially when it malfunctions. These are things you need to know about your RV.  

How Electricity Works in an RV

Highschool formulas can come in handy in getting to know your RV. There is a solution that you have to keep in mind when knowing the maximum number of electrical devices that you can plug at the same time. The equation is: watts= amps x volts or w= a x b. Does this formula ring a bell? Watts here signifies your overall power.

Make sure you stay within the available wattage so that your circuits run efficiently. Otherwise, you might trip your RV's whole electrical system. It's a hassle when you're peacefully enjoying your vacation, and something like this happens.

What Size of the Wire for 50 amp RV Service Do You Need?

Copper wires are different from aluminum wires. Use size No. 4 AWG for a 50 amp wire. That is the size of the wire for 50 amp RV service. Large wire diameters usually come in smaller numbers. For instance, No. 2 is bigger than No.4. Take note that there are various types of Aluminum Wires. While THWN and RHW are the most common ones, 40 amp uses No. 6 wires.

Two Electrical Systems in one RV

RV owners must know that an RV consists of two electrical systems. First is the 12-volt system, which is powered by a battery. This can power appliances such as the heater, furnace, water pump, refrigerator, or even your living space inside the RV.

The 120-volt system, on the other hand, is powered by the RV electrical plug or a generator. This system powers bigger electrical appliances such as your television and your kitchen appliances that consume more electricity. The important thing is that you remember what size wire for 50 amp RV service.

Step by Step Instructions

  1. Complete Shutdown - To avoid being electrocuted, you have to turn off the main breaker to manipulate the wires in it. To do this, you have to pull the control lever down to the "off" position. You may also double check by testing some devices before proceeding to the wire manipulation.
  2. Wire Test - Pull the wires then connect all of them to the panel, which is the outside receptacle. Next, install your double-pole 50 amp breaker into your sub-service box. Please take note of the colors of the wires. These will assist you in spotting the location and the placing of the wires. 
  3. Know your Colors - Do you see the red wire? Connect it to a terminal on the outlet side of the breaker. After connecting that, proceed to the black wire. Look for the other terminal, which is located in the outlet area of the breaker. The white wire has to be connected to the neutral bus-bar. The green wire, which is the bare one, should be connected to the grounding block.
  4. Wrapping it up - The green one is the half-round receiver. Before wrapping things up by making your final connections, wire the receiver to the other side of the half-round receiver. The white-colored one is your terminal screw. You need to connect the red wire to the Y configuration and to one of the screws. On the other side of the breaker, connect the black wire to the X configuration. This is the same for the other screw on the breaker. Take note that X and Y configurations are interchangeable. 
  5. Final Test Flip the lever into "on" to switch the main breaker. After that, switch the double-pole breaker to power. This should serve as your new 50 amp outlet. Place the probes on the receivers correctly, one for the hot receiver and also on the neutral receiver. One hundred twenty volts is the expected reading. If you try placing these probes on the hot receivers, it should have a reading of 240 volts. After accomplishing all of these, especially after trying out the voltage meter, you can test it on your RV.  

Congratulations! You are now ready to go out on a road trip with your RV. Make sure the switches work smoothly, though.  


Wiring up your own RV isn't much trouble. However, it is always advisable to take precautionary measures when handling wires and electrical systems. Treat all the wires as if they're live. Recheck the switch before you open up your RV. It is also good to call a professional for help when in doubt. These skilled and knowledgeable individuals will fix your RV in no time.   

You can now readily answer questions like “what size wire for 50 amp RV service?” These basic know-hows will not be difficult to unlock with enough research and on-hand experience. Before handling your RV with care, your safety should be of utmost importance. Do not risk safety with unsure situations. 

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