Home electrical projects can be interesting and fun. But they can also have you using the wrong type of wire for your connections. This is not a great idea as you have to worry about the length of the wire and the electrical loss over that distance. Plus it may not be safe to use the wrong wire.
The type of wire you should use is often debated. Some people will suggest you use AWG no. 4 wire which can handle up to 70 amps. Other people will say to use 6/3 wire which is rated for 55 amps. Both answers are correct and you should not use anything lighter than 6/3 wire for your RV 50-amp service.
To learn more about this project, just continue to read our article. It has the information you want to know about so you can do your RV wiring project correctly. Picking the right size of wire is vital to having a safe and successful use of the electricity running through the wire.
The first thing to remember when you are going wiring shopping is that the lower the gauge number the thicker the wire. The second thing to remember is that the thicker the wire, the more amperage it can handle without overheating.
The best two selections of wire you can choose will be either 4 or 6-gauge. Anything thicker than that would be over-kill for 50-amp service. If you find that the number 4 gauge wire is too expensive, the best gauge to get would be the 6/3.
This gauge of wire can handle 55 amps with ease which is 5 more than you need. The trouble with going with thinner wire like 8 gauge is that the wire is not rated for 50 amps and can overheat on you.
When it overheats, the wire can start a fire if the conditions are right. Picking the right wire is essential to protecting your property and family. Plus, 6/3 wire is used for residential wiring which the RV will fall under.
If you are in doubt, ask the electrical supply store where you are buying which gauge is best. They may say 8 gauge is good enough but it is not. There are some flaws to that wire that make using 6 gauge better.
There are some different regulations on this topic. Some new electrical regulations are saying that it is okay to use 8 gauge wires on a 50-amp circuit breaker. That is even though this wire is only rated for 40 amps.
The rule goes on to say that if the 8 gauge wire is used for electric heat-resistant flow then it can be rated for 50-amp service. However, this does not mean 8 gauge is good for motor loads.
The 6 gauge or 6/3 wire is rated for 55 amps and that is the best wire to use when hooking it to a 50-amp circuit breaker. There is no 7 gauge wire so you have to pick one or the other.
To be on the safe side, the 6 gauge is the best option of the two. This applies to three-phase circuits, single-phase circuits, and voltages of all variations and sizes.
Distance will be a factor in the size of the wire you will use. If you are only going 100 feet or shorter, then 6 gauge is the best option. If you are going longer than 100 feet, then you would need to go to the number 4 gauge to make up for the power loss over the distance
The NEC (National Electrical Code) has a good wire chart that helps explain what types of wire, conductors, and temperatures are for each wire gauge. You can read the chart at this link as well as explore the NEC code prior to starting your wiring project.
What will influence your purchase and eventual wiring will be several factors. The first will be the length of the wire you will need. When you go beyond 100 feet, new equations come into play and you will have to use a wire gauge that will help stop the 20% voltage drop that occurs.
The second will be the type of wire material inside the insulation or otherwise known as conductors. There is copper and aluminum wire. The latter is cheaper and lighter but it is also smaller than the copper wire.
By smaller, it is meant that if your project calls for 6/3 copper wire, to get the same efficiency, etc., you would have to use 4 gauge aluminum wires. Some people may recommend 8 gauge wire as it can be rated for 50 amps. However, that gauge of wire can overheat and start a fire.
It is best to go with the 6/3 wire to make sure your project and RV are safe from any risks.
No, it cannot. The 10 gauge wire is almost half the size of the 6 gauge option and it is not rated for 50 amps. This size of wire is only rated for 30 amps making it perfect if your RV only needs 30 amp service.
If you try to save money and wire 10 gauge wire to a 50-amp circuit, then you are asking for trouble. The wire will overheat and if it does not cause a fire, it will burn itself and make you replace it with the proper gauge.
It is said that the longer the run of the wire and the thicker the insulation, you can use 10 gauge wire on 40 amp services. What this means is that the 10 gauge wire is only good for 220 volts. It is not good for 240 volts of power.
If you need 220 volts, 30-amp service then the wire to use would be 10 gauge. 8 gauge is also good for this option as it is rated for 40 amps and sometimes 50 amps of service. It just depends on what the wire is going to be used for that makes the difference in the rating.
It can be under certain circumstances but it is best left to be used for 40 or 30-amp service and not used for 50 amps at all. When you need 240 volts and connecting to that much power, the 6/3 wire is the best option to use.
The reason for this is that 8 gauge can carry 50 amps if the temperature outside is -40 degrees F. But, if that wire is exposed to higher temperatures for a longer amount of time, then it starts to lose its conductivity.
To use 8 gauge wire you would have to make sure it is installed in a very cool, dry location. Copper wire becomes more electrically insulating as the area gets cooler.
Most people do not live or camp in -40 degrees F temperatures so sticking with 6/3 wire is the best option. That way your wire and RV, etc., are fully protected from any overheating that could possibly take place if you use 8 gauge wiring.
The choice is yours to make and the price will certainly tempt you to use the lower gauge wire instead of the best wire for the task.
Under ideal conditions, the best wire to use for 50 amps will be a 6/3 gauge wire. This is the copper version of the two possible wire types you can use. Even though copper is more expensive, it is the better of the two types.
When you are thinking of using aluminum wires for your project, then you cannot use 6 gauge wires for 50 amps. To get the same efficiency, etc., you would have to go to a 4 gauge aluminum wire.
This is up to 75 feet. At 100 feet, the charts are recommending that you go to 4 gauge copper wire and 3 gauge aluminum wire for the same project. Distance has a lot of say in which wire you will use.
If you are going to go to 200 feet, then the copper wire should be rated at 2 AWG and the aluminum at 1/0 AWG. The wire keeps getting thicker for every 50 feet beyond 200. Remember, the lower the gauge the thicker the wire. The higher the gauge the thinner the wire.
This going to a thicker wire over long distances is to protect your electrical current supply and offset the 20%+ voltage drop that occurs the further you go.
The reasoning is the same here as it is for copper wire. The further the distance you go the thicker the aluminum wire has to be. However, since 6 gauge aluminum does not work as well as 6 gauge copper you have to go to 4 gauge aluminum to get the same results.
4 gauge aluminum wire is rated for 55 amps at 140 degrees F. It is rare that you will run into hotter temperatures than that in this lifetime. That is the same rating 6 gauge copper wire has.
Then 6 gauge aluminum has the same rating as 8 gauge aluminum. The pattern continues the further you go down the gauge list. The aluminum wire will always have to be thicker than the copper wire to do the same amount of work.
Of course, for both copper and aluminum wires, there will be fluctuations in the wire size due to building code, potential voltage drops, material, duty cycle, and ambient temperature.
That means before you buy your wire, you should check the building code for your area as well as the NEC electrical code to make sure you know which wire to buy.
This length of wire is perfect for both 6 AWG copper wire and 4 AWG aluminum wire. The only time you have to worry about changing the wire gauge is when you are going longer than 100 feet in length.
For 120 or 240 volts, 100 feet is considered the rule of thumb for wire gauges. At that length, you are remaining at those gauge sizes till you get to 200 feet. Then you should be at 4 AWG and 3 respectively.
The further you have to wire, the thicker the wire has to be to accommodate the voltage drop that takes place. The 240-volt service does not need to go much lower than 3 AWG till you reach 300+ feet and the aluminum will go to 1 AWG for the same distance.
Make sure you are aware of the building code in your areas. Since different cities and states adopt different regulations, then you should contact the building code of the area you live and see what they say.
Make sure to obey the rules and regulations as inspectors can make you tear it all apart and do it all over again at your expense.
For 120-volt service, you will need to go to 1 AWG copper wire and 2/0 AWG for aluminum wire. When it comes to 240 volts, then the story is a bit different.
The copper wire rating for this distance is 4 AWG and the aluminum rating is 2 AWG. Remember, the aluminum wire always has to be one gauge thicker than the copper wire to handle the same workload and bring the same results.
There will be the same exceptions to the rules as there are for 100 or 200 feet of wire. The only difference in the wire gauge rating will be in the 240 three-phase circuits. The copper wire stays at 4 AWG but the Aluminum AWG goes to 3 instead of 2 AWG.
There are different charts you can use depending on which style of electrical current you want to use. You can look at those charts at this link. The series of charts includes the 480-volt system just in case you are working with that high of voltage and need to know which wire to use.
Also, you need to be wary of which wire you are connecting to the circuit breaker. The thinner wire is always in danger of overheating and you could end up with just melted wire, the best case scenario, or the overheating heating started a fire, the worst case scenario.
We will provide a wire size chart for both the 240 single-phase and the 240 three-phase electrical circuits. That will provide you with the best picture of what you will have to deal with.
1. 240 volt single phase
|Voltage||Distance||Copper Wire Size||Aluminum Wire Size|
|240||50 feet||6 AWG||4AWG|
|240||75 feet||6 AWG||4 AWG|
|240||100 feet||6 AWg||4 AWG|
|240||200 feet||4 AWG||3 AWG|
|240||250 feet||4 AWG||2 AWG|
|240||300 feet||3 AWG||1 AWG|
Information for both charts taken from https://portablepowerguides.com/50-amp-wire-size-chart/
2. 240 volt three phase
|Voltage||Distance||Copper Wire Size||Aluminum Wire Size|
|240||50 feet||6 AWG||4 AWG|
|240||75 feet||6 AWG||4 AWG|
|240||100 feet||6 AWG||4 AWG|
|240||200 feet||4 AWG||3 AWG|
|240||250 feet||4 AWG||3 AWG|
|240||300 feet||4 AWG||2 AWG|
As you can see, the copper wire does not need thicker wire the further it goes. It is fairly stable over long distances.
There are a couple of ground wire gauges you can use. Certainly, the 4 AWG gauge wire will work. However, this is slightly overkill and may be thicker wire than you would really need.
The ideal thickness would be 6 AWG gauge copper wire. This is the perfect size as you will be using 6/3 or 6 AWG gauge wire in your project. It is recommended that the same gauge of wire be used for hot, neutral, and ground wires.
While 8 AWG wire is rated for 50 amps some of the time, it is not recommended for use as a ground wire. If you try it, then most likely you will fry the circuit and cause a lot of damage to your electrical system in the process.
This rule is the same for 20 and 30-amp circuits. You will want the same gauge of wire for both of those systems. The 7 or 8 AWG wire is perfect for 40-amp service and possibly 30-amp. But the latter will work with 9 or 10 AWG gauge wiring.
Keep the ground wire the same gauge that the other wires have to be and you should be fine.
There should only be 4 wires in a 50-amp service. This size of service equates to 240 volts and that means you will have 2 hot wires and 1 ground as well as one neutral wire.
The most power you will get out of a 50-amp service is 12,000 volts. That should be more than enough to power all your appliances and other electrical devices requiring this much electricity.
Then almost all larger RVs use a double-hot-pole or double-bus installation. What this does is allow the RV to bring 120-volt service to two different 120-volt circuits at the same time.
This way you can always access that maximum of 12,000 volts even when you are using your computer and printer, etc. If you use a smaller gauge wire, then you run the chance of overheating that wire and causing you more problems than you want to deal with at the time.
The thing to watch out for here is not to listen to those people who say you can use different lighter gauge wires on a 240-volt, 50-amp service. While most RV outlets have 120-volt outlets, that does not mean you change the wire for the 50-amp service. That wire has to remain at 6 AWG or 6/2 gauge.
The 120-volt outlets are simply connected to one of the two hot wires in the 6 AWG wire.
If you know what you are doing, you won’t need to hire a professional to do the work. Although to pass inspection, the professional may have to do the final connections for you. Here are the steps to follow:
1. Turn off the power to the house or garage or shed you are doing the installation.
2. Look at the breaker panel for vacant breaker spots
3. Make sure the power is turned off and then install the breaker into the vacant spot
4. Connect the 50-amp electrical wires to the breaker, make sure it is 6 AWG if you are under 100 feet in length
5. Turn the power back on after putting the breaker panel back on
6. Test the outlet to make sure the power is going to the right terminals. If you haven’t cross-wired the outlet, then everything should read fine on your meter.
If you are in doubt, have a professional inspect your work to see that everything is done right. For those who do not like working with electricity, hire a professional to do all the work for you.
When you use the right equipment and the right materials, you can expect to have long-lasting electrical service. Part of the right materials is using 6/3 or 6 AWG gauge wires for your 50-amp electrical connection.
It never hurts to get advice from professionals. That way you can avoid any re-dos when inspection time comes around. Take advantage of all your resources and never go to a lighter gauge wire.
Use the right gauge of wire all the time and make sure they are all the same size when you connect them up.