A Guide to Recommended Wire Sizes For 200 Amp Electrical Service

If you need to know what the recommended wire sizes for 200 amp electrical service are we’ve got you covered. Before installing an electrical service it is important to know what size wire is needed, (see also: Electric Hot Water Heater: What Size Wire Do I Need?)so we look at what sizes are best to use.

If you need to know what the recommended wire sizes for 200 amp electrical service are we’ve got you covered. Before installing an electrical service it is important to know what size wire is needed, so we look at what sizes are best to use.

Recommended Wire Sizes For 200 Amp Electrical Service

We’ll consider how to calculate the wire size, and why it is important to know the distance that the wire has to run. Protecting the wiring is important, so we’ll consider the kind of conduit needed as well as the kind of ground rod required.

Working out voltage drop and knowing what NEC codes apply is essential to choosing the correct size of wire for 200 amp electrical service (see also: What Size Wire For A 100 Amp Service). Finally, we’ll compare the three different types of wire that you can use for your 200 amp electrical service.

Calculating Wire Size

To calculate the wire size you’ll need to know the distance that the wire has to run and the amps that it needs to carry. The voltage drop increases with the length of the wire. As the distance gets longer the resistance increases, this is known as impedance.

To counteract this the wire gauge size has to be increased. For proper performance a 3% or less voltage drop on feeder cables or branch circuits is recommended by the NEC.

As an example beginning with 120 volts at the start of a run of wire you should not have less than 116.4 volts at the other end. It should be noted that temperature can also have an effect on voltage drop.

Know Your Distance

To accurately determine the correct wire needed you have to know the distance that it has to cover. This allows you to calculate the voltage drop over that distance and hence the size of wire that you will need to use.

For #2/0 copper wire a 5% voltage drop at 200 amps can be expected. This means that your service has to provide 240 volts for this type of load.

To average a 3% voltage drop, which is the maximum allowed, you would need #2/0 copper wire for a run of 50 feet, #3/0 copper wire for 100 feet and #4/0 copper wire for 150 feet.

If you are using aluminum wire you’ll need #4/0 aluminum wire for a run of 50 feet and aluminum 300 kcmil for 100 feet. By adding 20% more amps for every 100 feet you can ensure that you are not using excessively small wires.

Types Of Conduit

The purpose of conduit is to protect the wiring from damage. The type of conduit used for the wiring will depend on whether the wires are running above ground or below ground.

Above ground installations normally use flexible and rigid conduits whereas underground installations have to use solid PVC conduit.

The minimum requirement for underground service is a 1.5 inch schedule 40 or 80 PVC conduit. However, if you are running three wires in the same conduit this will need to be increased to 2 or 2 ½ inch.

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Underground 200 Amp Wire Size For Long Runs

If you are running wires underground for 200 amp electrical service you’ll need to know what type of wire is best to use and what distance it will cover. For a maximum distance of 50 feet you can use either #1/0 copper wire or #2/0 aluminum wire.

At 100 feet use #3/0 copper wire or 300 kcmil aluminum wire, and at 150 feet use 300 kcmil copper or alternatively 600 kcmil aluminum wire. Longer distances such as 200 feet will need 500 kcmil copper or 1000 kcmil aluminum wire.

Size Of Ground Rod For 200 Amp Electrical Service

Every home needs a grounding system. The local ground in the electrical panel attaches to a conducting object that is in direct contact with the earth. Ground rods are the most commonly used grounding system for residential purposes.

A ground rod needs to be at least ⅝ inch in diameter and between 8 and 10 feet long with a clamp and an appropriate ground wire.

The ground wire for a 200 amp electrical service should be a #4 AWG copper wire or a #2 AWG aluminum wire which runs from the grounding electrode to the main power panel.

The ground rod has to be driven into the ground to at least 8 feet and then cut back close to the ground. The clamp and the wire are secured tightly to the top of the ground rod. In areas of high soil electrical resistance it may be necessary to have two ground rods.

A second ground rod is necessary where the first doesn’t meet NEC requirements of 25 Ohms or fewer. In these instances the ground rods should be at least six feet apart and connected by a grounding wire.

The material used for the ground rod is typically galvanized steel but can be stainless steel, copper, or zinc coated steel.

Working Out Voltage Drop

One of the first things you will need to do is to measure the voltage at various points along the electrical service using a voltage meter. The greater the distance from the power source such as the generator the more the voltage will drop.

Voltage drop is the loss of voltage that happens over the length of the wire due to natural resistance. The highest reading you will get comes from directly above the power source.

The lowest reading will be roughly 25–30 feet away or closest to where you want to plug in equipment. To work out the average drop for all the readings taken between these two points subtract each reading from the ones either side of it.

Distance dictates voltage drops so the further the wire has to travel the bigger the wire you will need. The NEC recommends that any setup with over a 5% voltage drop should upgrade the wire size. The gauge of the wire has to increase to offset the voltage drop.

An electrician will typically recommend adding 20% more amps for every 100 feet of distance covered.

Local Permit Requirements & Electrical Codes

Recommended Wire Sizes For 200 Amp Electrical Service

Before you decide on the material for your wiring, whether that is copper, aluminum or copper-clad aluminum you will need to look at the local permit requirements and electrical codes.

It is important to know the different regulations and rules that dictate wire installation in your local area. It may be that the local utility company requires the use of particular electrical brands or types of wiring.

NEC or National Electrical Code sets the basis for all electrical codes, but local codes can exceed these requirements. Local ordinances can either adopt or change the NEC to the needs of the area but cannot go below the requirements in them.

Minimum Requirements For 200 Amp

AWG or American Wire Gauge is the standard for sizing electrical wiring. A 200 amp electrical service requires either #2/0 AWG copper wire or #4/0 AWG aluminum or copper-clad aluminum wire.

These are the safest wires to use as they permit the use of full amperage of the electrical service without too high a voltage drop. If anything smaller than these wires are used it will increase the voltage and potentially cause wires to melt.

By using the correctly sized wires you are protecting your electrical services but also increasing the lifespan of your wires and connectors by preventing resistance buildup and overheating.

The length of wiring needed, and the associated voltage drop will determine which wire is used. Longer run will require thicker gauge wire while runs above 100 ft will move from AWG to kcmil wire which is thicker for use over greater distances.

How Is 200 Amp Electrical Service Different?

The difference between 100 amp and 200 amp electrical service is that the latter can handle a higher overload capacity. The 100 amp service is more susceptible to being overloaded. To find the right service you will need to know how many amps of current are being used.

The recommendations for the wire sizes for 200 amp electrical service are made with the 83% standard in mind. This means that the wire’s ampacity shouldn’t be less than 83% of the main service’s rating.

Although this rule only applies to services which are rated between 100 and 400 amps. The sizing also only applies to single phase services not triple phase.

Choices Of Wire Type

When choosing which type of wire to use for 200 amp electrical service you will have a choice of three, copper wire, aluminum wire and copper-clad aluminum wire.

Copper Wiring

Copper wiring is the preferred choice for many electricians particularly for branch circuits. This is because copper wire has many advantages and benefits including providing the best protection against surges. In the event of bad wiring it will also protect your equipment.

The high conductivity of copper wire makes it second only to silver for this purpose. As it is so conductive the size of wire needed is smaller than that needed for other materials such as aluminum.

Its conductivity also gives copper high heat resistance, more so than aluminum. This means that it doesn’t expand and contract, so cables stay tightly in place with no movement.

As a metal copper is corrosion resistant and will only develop a greenish tarnish which doesn’t interfere with its conductivity.

Copper wire is a more affordable option as due to its excellent conductivity it can handle a higher electrical load with half the diameter of aluminum wire. Due to its ability to be thin while still being conductive it is also a very malleable material with less risk of breaking.

For the purpose of distance copper can be used for longer expanses due to its superior conductivity.

Pros

  • Highly conductive material
  • Heat resistant
  • Corrosion resistant
  • Malleable
  • Better over long distance

Cons

  • More expensive to install
  • Heavier than aluminum

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Aluminum Wire

Aluminum wire has benefits over copper that are worth considering. It is a cheaper alternative to copper and in the long term the savings can be substantial. In addition it is a lighter material. Having said that, aluminum is less conductive and ductile than copper.

For installation aluminum is easier to install as it is highly bendable as well as being very light. This reduces the amount of time that a typical installation will take.

However over a given length it does lose voltage and due to its tendency to corrode more quickly the connection points are at greater risk than with copper wire. This kind of corrosion can cause shorts and other electrical problems.

Aluminum is more susceptible to heat and this expansion and contraction can work connections loose making the possibility of fire hazards greater. It is also necessary to have all the lugs and connectors aluminum rated when using aluminum wire.

Pros

  • Lighter material
  • Easier to bend
  • Lower cost than copper

Cons

  • Prone to corrosion
  • Susceptible to heat

Copper-Clad Aluminum Wire

As a compromise between the two previous types of wire copper clad aluminum wire features the best of both. It has a lower level of conductivity than pure copper wire as it is basically aluminum wire wrapped in a coating of copper.

However, it does cost less than pure copper wire and is still lightweight. This makes it slightly easier to install. Copper-clad aluminum wire is very versatile and is used in a variety of applications.

As the core of this wire is made from aluminum it isn’t as strong as copper wire and is prone to breaking. Additionally, despite being more conductive than aluminum wire it is still not as conductive as pure copper wire.

Pros

  • Cheaper than pure copper wire
  • Lightweight and easy to install
  • Versatile

Cons

  • Not as strong as copper
  • Lower conductivity

Conclusion

The recommended wire sizes for 200 amp electrical service will depend on the distance of the run of wire. A minimum requirement is #2/0 AWG copper wire or #4/0 AWG aluminum or copper-clad aluminum wire.

The material that the wire is made from will also determine the size that is used. Aluminum wire will typically be of thicker gauge than copper wire as it is less conductive than copper.

We hope that this guide to the recommended wire sizes for 200 amp (see also: What Size Wire For 50 Amp RV)electrical services has been useful and that you have found it informative and helpful.

Frequently Asked Questions

How Far Can You Run Wire Before Voltage Drop?

For a 120 volt circuit you can run 50 feet of 14 AWG cable without going over the 3% voltage drop permitted. For the same circuit you can use 60 feet of 12 AWG wire and 76 feet of 8 AWG wire.

What Is The Advantage Of 200 Amp Service?

A 200 amp service panel will provide more electrical current than a 100 amp panel and allow you to safely power larger electrical appliances or multiple smaller appliances simultaneously.

What Is The Maximum Amperage For 200 Amp Service?

A 200 amp service panel will support up to 48,000 watts of power. However, it is not recommended that you run your system at full capacity, 80% is recommended. The demand on a 200 amp panel shouldn’t exceed 160 amps.

Eddie Meyers
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Eddie Meyers
My name is Eddie, and I am an RV enthusiast! I have enjoyed traveling all my life, and want to give my family the same opportunities to see as much of the world as possible. As I’ve gotten older, I’ve discovered how great RVs can be for vacations with a young family. Here at RV Lifestyle Experts, I want to share my experiences, the tips I’ve picked up along the way. I hope that our guides can encourage you to try the RV lifestyle. I promise you that you won’t regret it!
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