[NEC] 200 Amp Service Wire: What Size For 50, 100, 150 Feet

200 amp service wires are quite big and can be used as 200 amp ground wires, or wires for 200 amp breakers. They can be either aluminum or copper 200 amp wires.

The common question for all these applications here is this:

What Size wire do I need for 200 AMP Service?

From the image above, it might look like using a #000 AWG wire for 200 amp service a.k.a 3/0 AWG might seem right because it has a 200A ampacity. But that is a wrong choice that will likely end up with you frying the wire.

In order to prevent frying a 200 amp circuit, the National Electric Code (NEC) recommends the following requirement:

Maximum loading for any branch circuit is 80% of the rating of the circuit for ampacity of wire for any load.  (NEC 220-2)

This is the recommended NEC 80% requirement for wire sizing. In other words, you’d need a wire with at least 250A ampacity to connect a 200 amp service when setting up your 200 amps breakers.

Looking at the AWG wire chart, you’d need an even bigger than #0000 AWG wire for 200 amps. Yes, that’s right – you’ll need to go beyond the AWG chart and look into the KCMIL wire chart.

Why?

KCMIL wires are typically bigger and can handle currents of 200 amps and higher.

Here is a shortlist of KCMIL wires that can be used as 200 amps service wires:

• 250 KCMIL wire with 255A amperage.
• 300 KCMIL wire with 285A amperage.
• 350 KCMIL wire with 310A amperage.
• 400 KCMIL wire with 355A amperage.
• 500 KCMIL wire with 380A amperage.

In our experience, the 250 KCMIL wire remains the perfect size wire for 200 amp service because it features 255A ampacity (a minimum of 250A ampacity requirement is satisfied).

Continue reading to discover how this 250A ampacity is calculated. On top of that, we’d also inform you why you’d need a bigger wire gauge if you want to send electricity 100 feet or 150 feet away from sub-panel. Plus, how to calculate what size wire you need in this case as well.

200 Amp Wire Gauge Calculation: What Size Wire You Need For 200 Amp Circuit?

To adequately determine the 200 amp wire gauge, you should first calculate the minimum ampacity requirements as per the 80% NEC rule.

For a 200 amp circuit, the calculation is:

200 Amp Wire = 200A × 100% / 80% = 250A Ampacity

It is always advised to leave 20% extra amps capacity for safety reasons).

That means that you can use a wire with an ampacity of 250A or higher in order to set up a 200 amp circuit.

As earlier stated, the 250 KCMIL wire is perfect for a 200 amp service since it has an ampacity of 255A.

Now, if the sub panel is some distance away like 50 feet, 100 feet, 150 feet, 200 feet etc., you will probably need to use an even bigger wire to counter the voltage drop.

The NEC 310-16 requirements cover this nicely:

How To Account For Sub Panel Being 100 Feet Away?

Truth is, electricity sent a long way from the sub panel causes voltage to drop with the distance.

To counter this drop, you need to boost the initial amps. That means that the circuit needs to handle more amps; in turn, the wire you’re using has to handle more amps.

How Much More Exactly?

According to the NEC 310-16 requirements, an estimate of 20% of the total amps for every 100 feet of a distance is recommended for a 200 amp copper or aluminum wire.

For instance,

If you want to use 200 amp service 100 feet away from the sub panel and you already know that such a circuit will need wires with at least 250A ampacity, you should increase the amps by 20% to get the true size wire for 200 amps at such a distance:

200 Amp Wire (100 ft away) = 250A × 1.2 = 300A Ampacity

Now, we need to get a wire with 300A ampacity or more. Check the KCMIL list above, and you’d agree with me that the 350 KCMIL wire is perfect for 200 amp service 100 feet away.

That’s because the 350 KCMIL wire boasts of a 310A ampacity.

You can make similar calculation for:

• 50 feet (10% addition),
• 150 feet (30% addition), and
• 200 feet (40% addition), and choose the corresponding KCMIL wire.

Hopefully, now the 200 amp wire sizing is a bit clearer.

You should also look into different amp wires and similar calculations for:

• 20 amp gauge size.
• 30 amp gauge size.
• 40 amp gauge size.
• 50 amp gauge size.
• 60 amp gauge size.
• 100 amp gauge size.

What Size Wire Do You Need for 200 Amp Service

The size of wire you’d need for the installation of your 200 amp service depends on the material of the wire you plan to use.

Let’s see some differences between aluminum or copper-clad aluminum wire and let’s see if you need to prefer one over the other.

The Length Your Service Wire Runs Matters:

GROUNDING ELECTRODE CONDUCTOR SIZING (Table 250.66)

Wire Sizes for 200 Amp Service

• Copper Wiring

Copper wiring has proven to be the best in the business and is often recommended for good reasons.

For starters, its high in conductivity, flexible and is heat and corrosion-resistant.

But, copper is expensive and is a bit hard to install. Here are more truth’s you need to know about copper wiring:

High Conductivity: By nature, copper is naturally highly conductive. Only silver has been able to beat it at that.

Since it is great at conducting electricity, you’re able to use it for much longer distances, and you can use a much smaller gauge than for aluminum.

Heat and Corrosion Resistant: Although copper may undergo color change as a result of oxidation, its performance isn’t affected in any way.

Copper is corrosion-resistant and will stand the test of time. It’s also has plenty of heat resistance to aluminum. Heat doesn’t make it flex or expand nearly as much, so it stays in place.

Flexible: Since copper wire uses thinner stands, it’s much easier to control, bend and wrap without breaking anything.

In for the Distance: Again, since copper both sturdy and highly conductive, it’s better for length and doesn’t lose its voltage over longer distances.

No doubt, copper is probably the best material for wiring, but it does have downsides, which we’ll touch on in the next section.

The Short Answer: When using a 200 amp service, you’ll want a #2/0 copper wire.

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• Aluminum

Aluminum exhibits less conductivity than copper and also responds more quickly to heat and corrosion.

To make up for the lack of conductivity, you’d also require a higher gauge – i.e, a thicker wire.

But, lots of electricians opt for aluminum for a couple of reasons.

The downsides of copper are that it’s costly, heavier, and trickier to install. And that’s precisely why electricians often choose to use aluminum.

Here are the main benefits of using aluminum wiring:

Easier Installation: Because Aluminum is much lighter than copper, aluminum is fast and easy to install. If you want a job done quickly, aluminum is the solution even when you account for the higher gauge needed for proper conductivity. Since it’s so lightweight

Cheaper: It has been proven without reasonable doubt that aluminum is more affordable than copper. It works well and doesn’t break the bank.

The Short Answer: For a 200 amp service, you’ll need a #4/0 aluminum wire.

• Copper-Clad Aluminum

Copper-clad aluminum is your third favorite option, and it offers some benefits of both past options.

Let’s compare it to the other two talked about above:

Cheaper but Not Cheapest: Copper-clad aluminum is much more affordable than pure copper but more expensive than aluminum.

More Corrosion Resistant Than Aluminum: Copper-clad aluminum wire keeps the aluminum safe from corrosion. Most aluminum needs an antioxidant coating connecting to the power terminal, but copper-clad aluminum doesn’t need it.

Good Conductivity: Again, copper-clad aluminum conductivity isn’t as good as copper but much better than aluminum.

The Short Answer: Like with aluminum, you’ll need a #4/0 copper-clad aluminum wire for a 200 amp service.

Other Factors to Consider

Before finally making up your mind, consider the following:

• Voltage Drop

The voltage at your circuit breaker should read 120 volts.

Voltage drop means how much power is lost as electricity moves along the wire to your appliances and devices.

You can improve your voltage drop by increasing the gauge of your wire.

• Distance

A Copper wire is recommended if you need power across distances longer than 50 feet.

A #2/0 copper wire and a #4/0 aluminum wire can maintain less than a 3% voltage drop over 50 feet. To go beyond 50 feet, you’ll likely need a higher gauge copper wire.

• Local Building Codes

Familiarize yourself with the electrical codes in your area by checking the National Electrical Code (NEC). You also need to be sure you have all the permits required for this type of work.

How Much Does it Cost to Install 200 Amp Electrical Service?

It costs anywhere between $750 and $2,000 to install a 200-amp electrical service.

A full reset with a new circuit breaker, though, could cost up to $4,500.

Can I Run a 200 Amp Subpanel off 200 Amp Main?

Technically speaking, this is possible. However, we’d recommend looking into a 400A service. You should check the power usage overall to ensure the subpanel isn’t drawing most of the power for just one or two applications.

200 Amp Service Wire From Meter To Panel

The wire size needed for a 200 amp service is 4/0 for aluminum and 2/0 for copper.

If it’s right next to it you can run 3/0 but if it’s a ways from the meter then use 4/0 assuming you’re within a couple of hundred feet of the meter.

What Size Wire For 200 Amp Service Underground?

• 125 Amps #2 AWG #1/0 AWG
• 150 Amps #1 AWG #2/0 AWG
• 200 Amps #2/0 AWG #4/0 AWG

And if you’re going to be starting any big motor loads across the line where the starting currents can be five to ten times the running currents, you might want to go up to at least 4/0 copper or maybe 350–400MCM Aluminum.

200 Amp Service Cable Price Per Foot

Home Depot sells service cable ($4.96 /ft.) and it is available for pickup.

40 Aluminum Wire For 200 Amp Service

In the U.S. it is suggested that:

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.

If anything is unclear, you can use the comments to pose a question and we’ll try to help you out.