What Size Wire Is Needed For 200Amp Electrical Service

When installing a 200 amp electrical service, you need to be sure you use the correct gauge wire. You'll need a permit to do the professional installation. Many areas still allow homeowners to obtain their permits. You'll need to check with your local building department to know if you can obtain the permit or if you'll need the help of an electrician.

Installation of 200 amp electrical service needs a #2/0 AWG copper wire or #4/0 AWG for aluminum or copper-clad wire inside a 3" conduit. Wiring a 200 amp electrical service is not a DIY job. It often requires a permit and professional installation by a qualified electrician following local electrical codes.

Power is received from the utility service lines and flows through the outside electrical meter base and then into the main electrical panel located in an attached garage, basement., or interior room.

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Wire Sizes For 200 Amp Service

AWG, American Wire Gauge, is the US standard for sizing electrical wiring.

Wiring 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.

The following table reflects wiring size, length, and voltage drop:

Service or Feeder Rating
(Amperes)
Copper Wire
(AWG or kcmil)
Aluminum or
Copper-Clad Aluminum Wire
(AWG or kcmil)
10042
11031
12521/0
15012/0
1751/03/0
2002/04/0
2253/0250
2504/0300
300250350
350350500
400400600
Source: NEC

Many electrical contractors opt to use #4/0 aluminum or copper-clad wire. 

For copper wiring, you'll need a #2/0 AWG copper wire commonly used for electrical wiring because it is more heat resistant than aluminum. Copper won't rust and is resistant to oxidation. 

For aluminum or copper-clad aluminum wiring, you'll need #4/0 AWG aluminum wiring. Aluminum wiring requires a larger size wire because it has a lower conductivity than copper. Aluminum wiring requires an antioxidant coating at the connection terminals to resist corrosion. Copper-clad aluminum doesn't require an antioxidant coating at the connection terminals.

Aluminum wiring is widely used because it costs less, is lightweight, and is more flexible than copper, even though copper is considered a better conductor.

Why Use Copper Wiring

Copper wiring is preferred for wiring. Copper wiring has many benefits including:

  • Conductivity: Copper wire is second only to silver in electric conductivity. Copper can handle a higher electrical load requiring the use of less insulation and a lower wire gauge. Copper wiring is about half the size of aluminum wiring for the same conductivity.
  • Heat Resistant: Copper wire conductive properties make the wire more heat resistant than aluminum wire. Copper wire does not expand and contract like aluminum which means the wire connections remain tight on lugs.
  • Corrosion Resistant: Copper is resistant to corrosion. Patina, a tarnish that develops on copper, occurs by oxidation however does not affect the conductivity.
  • Malleability: Because copper is highly conductive, the wire strands are thinner, making the wire more malleable without the risk of breaking.
  • Distance: Copper can be used over longer distances due to its highly conductive properties and heat resistance.

Why Use Aluminum or Copper-Clad Aluminum Wire

Aluminum wire is preferred on service entrance wire for several reasons, including:

  • Budget: Aluminum wire is preferred due to its lower cost. Aluminum wiring is cheaper to produce compared to copper wire. Aluminum copper-clad is preferred but does cost more than aluminum wiring.
  • Lightweight: Aluminum is lightweight and very flexible, making it easier to work with despite the wire gauge being near twice the size of copper.
  • Faster Installation: Aluminum is lightweight and flexible, meaning you can install it faster than copper, cutting installation costs.

Aluminum wiring expands and contracts with heat which causes the wire connection to loosen over time which raises the risk of an electrical fire. Aluminum service wiring is a grouping of smaller solid aluminum strands rather than one solid wire, making the aluminum wire safe to use in residential homes.

The Distance the Service Wire is Running

When calculating wire size, you need to consider how far the service wire will run from the meter to the electrical panel. The maximum voltage drop (we will discuss shortly) allowed is 3%. The voltage drop will often determine if you can use copper or aluminum wire and what gauge is needed.

Service Wire SizeDistance (Approximate)
to Maintain 3% Voltage Drop
Copper #2/0 Wire50 feet
Copper #3/0 Wire100 feet
Copper #4/0 Wire150 feet
Aluminum #4/0 Wire50 feet
Aluminum 300 kcmil100 feet
Distances may vary by location. Check with your local building department for requirements

Aluminum and copper wire is rated for 200 amp service. However, the aluminum gauge will be higher due to its reduced conductivity properties and heat resistance. You can use copper wire over a longer distance.

What is Voltage Drop?

Voltage drop is the loss of voltage that occurs over the wire due to natural resistance. The longer a wire runs, the more voltage loss that occurs. The wire gauge has to be increased to offset the voltage drop.

The voltage at the circuit breaker should be 120 volts. Using a voltage meter, take a reading at the appliance or the farthest device. Ideally, you should not have a voltage drop higher than 3%, or 117 volts, or 233 volts from a 240-volt circuit.

Check Local Electrical Codes & Permit Requirements

Electrical codes are set by the National Electrical Code (NEC) but can vary by location. Using a qualified electrician ensures your 200 amp electric service meets local codes and permit requirements.

The 200 amp wire size referred to in this article is from the NEC code and may vary from your local building code. Your local code will adopt or alter the NEC codes to fit their requirements.

Before the utility service can connect power to the house, you'll need a Certificate of Occupancy (CO). The permit allows for a final inspection to allow the electric service to be connected. The CO is issued after the electrical work has been inspected and passed by the building inspector.

Cost to Install 200 Amp Electrical Service

The cost of installing a 200 amp service will vary based on location and material costs in your area. The cost will also be determined by the work that needs to be done. Installing a 200 amp electrical service typically includes installing a 200 amp service wire, conduit, meter base, and a 200 amp electric panel.

Based on HomeAdvisor.com, the national average cost of a complete 200 amp electric installation will cost between $1,600 and $6,100, with a median cost of approximately $3,700, includes the following:

  • 200 Amp Service Panel: Average cost ranges from $500 to $4000, with a median cost of $2000.
  • 200 Amp Meter Base: Average cost ranges from $100 to $650, with a median cost of $450.
  • 200 Amp Service Wire: Average cost ranges from $1000 to $1500, with a median cost of $1250.

According to MidPenn Electrical, a leading electrical contractor in Pennsylvania, "a new 200 amp service can cost anywhere from $3,200 to $4,000".

Conclusion

Installing 200 amp wire is not a DIY project for homeowners. Wiring a 200 amp service panel is a big project that requires the services of a qualified and certified electrician. You may require a permit to install a 200 amp service. The electric service will need to be disconnected entirely in existing homes to install the 200 amp service.

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Hubert Miles

I've been conducting home inspections for 17 years. I'm a licensed Home Inspector, Certified Master Inspector (CMI), and FHA 203k Consultant. I started HomeInspectionInsider.com to help people better understand the home inspection process and answer questions about homeownership and home maintenance.

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