200 Amp Electrical Service Wire Size (Complete Guide) - Home Inspection Insider (2022)

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 get 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 minimum of 1.5 inches, schedule 40 or 80 PVC conduit for underground service. However, 2 or 2.5 inches is recommended if running 3 wires in the same conduit.

Wiring 200 amp service requires an electric permit and professional installation by a qualified electrician in accordance with local electric codes.

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

Wire Sizes for 200 Amp Service

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

Wiring a 200 amp feeder requires either #2/0 copper wiring or #4/0 aluminum or copper-clad wiring. Which wire is used is determined by the voltage drop and length of the wiring.

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

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

For copper conductors, 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 diameter 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 wirings appeal widespread because it costs less, is lightweight, and is more flexible than copper, even though copper is considered a better conductor.

Why Copper Wiring is Preferred over Aluminum

Electricians and homeowners alike prefer copper wiring, particularly for branch circuits. Copper wiring has many benefits, including:

• Conductivity: Copper wire is a highly conductive metal, second only to silver. Copper can handle a higher electrical load, so you can use a smaller gauge wire. Copper wire is about half the diameter of aluminum wire 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, so the wires remain tight on lugs.

• Corrosion Resistant: Copper is resistant to corrosion. Patina is a greenish-tarnish that changes the outer color of copper. Patina forms by oxidation; however, do 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 conductors can be used over longer distances due to its highly conductive properties and heat resistance.

Pros of Aluminum or Copper-Clad Aluminum Wire

We just discussed why copper is preferred; however, copper-clad and aluminum wire sizes are more popular on service entry wire for several reasons, including:

• Budget-Friendly: Aluminum wire is preferred due to its lower cost. Aluminum conductors are cheaper to produce compared to copper conductors. Aluminum copper-clad is better but does cost more than aluminum wiring. Aluminum costs much less than copper-clad and copper wires.

• Faster Installation: Aluminum is lighter than copper and very malleable for its larger wire gauge. Electricians find is easy to work because is lightweight and feeds well through the electrical conduit which makes for faster installation and lowers material and labor costs.

Aluminum wiring expands and contracts with heat which causes the wire connection to loosen over time, raising 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 Length Your Service Wire Runs Matters

When calculating wire size, you need to know how far the service entrance wires will run from the electrical meter base to the electrical panel. The maximum voltage drop (we will discuss shortly) allowed is 3%. The distance your service entry wire needs to travel will determine whether you use aluminum or copper wire and gauge necessary.

You can use aluminum and copper for a 200 amp service entry wire. However, the aluminum gauge will be higher due to its reduced conductivity and heat resistance properties. 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 size wire gauge has to increase 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%. For a 120-volt electrical circuit, the voltage drop should be no less than 117 volts. Likewise, on 233 volts on a 240-volt electrical circuit.

How Many Wires You Need for 200 amp Service

The type of wire you need will vary depending on your electrical system. The run from the meter base to the main disconnect box or main panel is 3-wire, consisting of 2 hot wires and 1 neutral wire. The neural and ground bars have electrical bonding connecting the bars.

The feeder run from the main electrical panel to the interior distribution panel (subpanel) is 4-wire, consisting of two hot wires, one neutral wire, and one ground wire. You don’t bond the neutral and ground bars inside subpanels.

What Size Conduit You Need for 200 Amp Service

An electrical panel has knockouts for connecting electrical feeder conduit. You can use either a 2-inch or 2.5-inch conduit based on the fill space you intend to occupy inside the conduit. If 3 or more wires are inside the conduit, the maximum fill space of 40%.

In Chapter 9, Table 5A of the 2017 NEC, a #4/0 Aluminum stranded conductor takes up 176.3mm² of fill space. If you multiply 176.3mm² by four gives you a total of 705.2mm² of fill space used by the entire feeder.

According to Chapter 9, Table 4 of the 2017 NEC, a 2″, Schedule 80 PVC conduit has 742mm² usable fill.

So, a 2″ conduit will suffice, or you can upsize to 2.5″ if you wish for ease of pulling. Keep in mind that the area of the wires must be less than 40% of the internal space of the pipe when 3 or more wires are present.

What Size Ground Wire for 200 Amp Service

The NEC is the electric code used in the United States. The minimum size for a grounding wire for 200 amp is #4 AWG copper or #2 AWG aluminum, according to Article 250 of the 2020 NEC.

The size of the primary conductor may need to increase for a variety of reasons, including the length of the run, available fault current, or any number of reasons. The NEC is a safety guide. Local municipalities set and adopt code guidelines. Call a local electrician or your city for specific guidelines.

GROUNDING ELECTRODE CONDUCTOR SIZING (Table 250.66)

What Size Ground Rod for 200 Amp Service

A ground rod needs to be at least 5/8″ (0.625) in diameter and at least 8 to 10 feet long with a clamp and the appropriate ground wire. The ground rod needs to be driven 8 feet deep into the ground and cut back close to the ground. The wire and clamp are secured tightly to the top of the ground rod.

Where there is a lot of electricity in the ground, a thicker #3 size wire may be required. New code requirements require two ground rods for regions with high soil electrical resistance.

Use the correct type of grounding rod. Pipe or rebar can also be used for grounding. The grounding rod must be galvanized steel and should be at least eight feet long.

How Many Ground Rods for 200 Amp Service

A ground rod that does not meet the NEC’s 25 OHMS or less requirement necessitates using a second ground rod, with the ground rods being at least 6′ apart.

You install a ground rod for a system, and the first ground rod has a resistance of 25 ohms or more. According to the NEC, you must install a second grounding rod. On the other hand, many contractors do not take ground resistance into account. They anticipate driving two ground rods to satisfy 250.56’s standards regardless of actual ground resistance. As a result, two ground rod connections are typical but aren’t always necessary.

The NEC article 250.53(B) requires you to space grounding rods at least 6 feet apart connecting by a grounding wire. However, this spacing is a minimum. When using the typical 8-foot or 10-foot ground rod, you get the best results by spacing them at least 16 or 20 feet apart, much farther than the minimum 6-foot spacing.

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 size wire 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 connect the electric service. The CO is issued after the electrical work has passed the building inspection.

200 Amp Electrical Service Installation Costs

It’s nearly impossible to accurately price the cost of installing a 200 amp entry service in a house. We need to consider numerous factors, like location, the amount of work required, and material costs in your area. 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, the national average cost of a complete 200 amp electric installation costs $1,900 to $7,250, with average cost of $4,650, including the following:

• 200 Amp Service Panel: Average cost ranges from $750 to $2000, with a median cost of $1375.
• 200 Amp Meter Base: Average cost ranges from $150 to $400, with a median cost of $275.
• 200 Amp Service Wire: Average cost ranges from $1000 to $5,000, with a median cost of $3,000.

According to MidPenn Electrical, a leading electrical contractor in Pennsylvania, “a new 200 amp service can cost anywhere from $4,200 to $5,000“. Therefore, the HomeAdvisor cost averages seem to be reasonably accurate.

Conclusion

Installing 200 amp wire is not a DIY project for homeowners. Wiring a 200 amp 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.

Also, see our guide, Wire Size for 100 Amp Electric Service.