What Size Wire Is Needed For 200Amp Electrical Service?

What Size Wire For 200 Amp Electrical Service? Full Guide

two Different 200 amp wires side by side

Whenever you decide to install a 200 amp electrical service, the size wire you need to use is determined by the distance of your run and the voltage drop allowable. Please note that installing a 200 amp service is not a simple DIY project and should only be done by professionals.

Determining Voltage Drop:

Using a voltmeter, measure the voltage at various points along your electrical service. The more distant from the source (such as generator or transformer) you are, the more you will find that it drops off.

Your highest reading will be from directly on top of your power source. Your lowest reading will likely be 20-30 feet away, closest to where you want to plug in equipment. Subtract each reading from its neighbor on either side until you have found an average drop for all readings taken between those two points.

Wire Sizes For A 200 Amp Service

To safely use a 200 amp electrical service, you will need to use #4/0 Aluminum, Aluminum Clad Wire, or #2/0 Copper. These are the safest wire sizes because they will allow you to use the full amperage of your electrical service without too high of a voltage drop.

Using anything smaller than #2/0 copper wire will increase your voltages (and maybe even start melting wiring). Sticking with larger wire sizes like this not only keeps your equipment running efficiently, but also increases the lifetime of both wires & connectors by preventing overheating and resistance buildup.

Why Choose Copper Wiring?

Choosing to use copper wiring will provide the best protection from surges and also protect your equipment in case of bad wiring. Copper wiring is typically cheaper than aluminum or aluminum clad wiring, so it may cost you less in the long run. Aluminum and aluminum clad wires look very similar to copper wiring in their appearance and general installation practices, but they lose more voltage over a given length of wire due to resistance. This means that if your service calculates to use #2/0 copper for 100 amps but you choose #4/0 aluminum instead, then you could be losing up to 50 amps of power because the wires are too small.

Why Choose Aluminum or Copper-Clad Aluminum Wire?

As stated above, aluminum wires lose voltage over a given length due to resistance. This can make it difficult to deliver maximum power to your home while also ensuring that bad wiring causes no damage or hurtful fires.

Another issue with longer runs of aluminum wiring is that the connection points will corrode more quickly than they would with steel and copper wiring. This corrosion can cause shorts and other electrical issues, so most installers recommend aluminum clad-copper wire (sometimes also called ACAW) in these cases because the base metal is copper and therefore does not corrode as badly when compared to aluminum alone.

Below is a list of reasons why someone would choose to use aluminum wire instead of copper wire.

  • Cost - The cost savings of aluminum wire in the long-term can be substantial. The initial cost of copper wire is more than aluminum, but when adding up all the materials and labor involved in a larger project, the price difference is negligible compared to using aluminum wire, which will save time for installers and companies.
  • Weight - Aluminum weighs much less than copper does by volume, so it's easier to transport when many miles have to be covered.
  • Corrosion Resistance - Aluminum oxidizes at a much slower rate when exposed to air when compared to copper wires. This means that aluminum will not corrode as quickly after being installed in wet or damp environments like bathrooms or kitchens where there may be exposure to water from sinks and showers.
  • Installation Time - The time it takes to install wires with aluminum is reduced because it's easier to bend and doesn't take as many fittings. This means that the cost of an installation will go down due to less time spent on installations.

Check Your Local Permit Requirements and Electrical Codes

Knowing the different rules and regulations that govern wire installation can make a big difference. Your local utility company may charge less for running the wire through conduits if you upgrade to aluminum or other more durable wiring. Be aware of any permits or fees that may be required, and whether your locality requires you to use particular brands and types of wiring. You never want to complete a wiring job only to find out that you have to remove it all and start over because it wasn't done properly or according to the electrical codes or permits.

Check the Distance of the Wire Run

When you know the distance that the wire must run, you have a better idea how much voltage drop there will be. If you want to limit any wire runs to less than 50 percent of a volt, then 200 amp service requires either #2/0 copper wiring or #4/0 aluminum or aluminum clad wiring. Which wire used is determined by the voltage drop and length of the wiring. For #2/0 copper wiring you can expect up to 5% voltage drop at 200 amps, which means your service must provide 240 volts for this kind of load. This type of wiring has a minimum breaking strength that's nearly twice as strong as aluminum.

Service Wire Size Distance to average a 3% Voltage Drop
Aluminum 300 kcmil100 feet
Aluminum #4/0 Wire50 feet
Copper #4/0 Wire150 feet
Copper #3/0 Wire100 feet
Copper #2/0 Wire50 feet

Cost to Install 200 Amp Electrical Service

The cost to install a 200 amp electrical service will always vary depending on many different factors. These factors will be listed below.

  • Electrician will determine the cost of wiring based on their average rates in your area.
  • The size of the service box, whether it's a 100 or 200 amp panel is another factor that can increase or decrease the cost to install a 200 amp electrical service.
  • Another factor is how much work must be done to prepare for the installation (moving building structures, drywall tools).
  • More factors include if it's overhead or underground service, and any other services either preceding or following this one (circuit breaker panels, storm panels).

A 200 amp electrical service will require aluminum clad wiring, #4/0 aluminum, or #2/0 copper wiring.

The cost of installing these wires is usually between $1,000 and $1,500 for overhead systems and $1,500 to $3,000 for underground systems.

If the wires are too small they can create circuit breaker problems when they heat up during operation. If the wire is too big it won't allow adequate voltage drop so that equipment can operate properly. That's why this job is left up to an electrician because he or she has all of the tools needed to complete this task correctly by understanding all of the factors involved and the equipment that will be connected to the line.

How many amps can you put on a 200 amp panel?

The amount of amps you can run at any given time on a 200 amp panel is determined by the voltage drop.

Typically, the maximum voltage drop in a residential electrical system should not exceed five percent. That means if you have 100 amps available at 208 volts, the total load on the line shouldn't be more than 2000 watts. Like I said earlier though, this will all depend on how big your service is and how much wire is needed for that service.

How do I calculate wire size?

Calculating wire size is fairly simple, but in order to do so you need to know the distance the wire will run and the amps it is expected to carry. You can find out how far your wire needs to be by multiplying the length of each wall by 2, then add 10% for trusses/ducts/stove runs, etc.

For example: If you have a room that is 14 feet x 20 feet with 5 foot of overhang on one end.
  • 14x20 = 280 feet

280ft x 1.1 = 308ft of wire needed.

If you are running more than one line, just add them all up at the end. When doing this make sure you get #2 copper for between 150-200 amps or #4/0 aluminum or aluminum clad for 200 amps or more.

To help you get an idea of how far your wire will need to run, see the example below:

2x4 wall - 80ft (16ft on center)

5x8 Wall - 200ft (20 ft on center)

6 x 12 Metal Building - 240 ft (20 ft on center).

You can find out the amps by checking the nameplate on your equipment and adding them together. For example: If I'm pulling 120 volts and i am running two electric baseboard heaters each drawing 30 amps, all together 60 amps would be my total. Please note that if you are pulling 240 volts the calculation is different so check with an expert before attempting this yourself.

What's the difference between 100 and 200 amp service?

The major difference between these two amp service is the fact that the 100 amp service is more susceptible to overloading. A 200 amp service on the other hand is able to handle a higher overload capacity.

In order to determine the need for a 100 amp service or a 200 amp service, you will first have to find out how many amps of current is being used. An electrician will be able to help you with this determination and install the correct wiring required for your household appliances and equipment.

200 Amp Wire Size

The best wire to use for 200 amps is #2/0 AWG. For the most demanding of situations, #1/0 AWG is recommended. These wires will have a thicker covering with a copper core in the middle to handle 200 amps of current safely and efficiently.

If you do not plan on installing a large washer and dryer at the same time as using your electrical appliances, then a 100 amp wire is going to be fine for your household usage.

A general rule to follow with wiring is that it should be 12-gauge or larger. A 12-gauge cable has more than enough capacity for any home appliance and even multiple smaller appliances being used simultaneously.


To use a 200 amp service, you need #2/0 or #4/0 wiring. Contact an electrician for more information. Making sure you have the right wire size will ensure that your electrical equipment operates properly and does not cause a dangerous situation.

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