200 amp wire size – Gauge, Length & Voltage

200 amp wire size

Which is the ideal wire gauge, voltage, and length for a 200 amp circuit?

Key Takeaways

  • A 2-gauge wire is ideal for a 50-amp panel.
  • The neutral and hot wires should be the same size to ensure they transmit the same current.
  • According to the NEC 310-16 rule, you should increase the amps for a 200 amp by 20% for every 100 feet. This will help account for the voltage drop.

Understanding the correct wire size and proper grounding for your purposes is essential in helping avoid negative consequences. According to the National Electric Code (NEC), the load capacity placed on any branch circuit is 80% of the circuit’s ampacity load rating. 

In this case, the Amp Service Wire Size must be at least a 2/0 AWG of copper wire when installing a 200-amp panel.

It’d help if you wired larger than a 4/0 AWG when using copper-clad or aluminum. Before determining if the 200 amps wire is best for you, think about a few things.

  • What length does a typical 200-amp service wire size require?
  • How do you plan to account for any voltage drops that may occur when running the wire?
  • What intended voltage will you apply to the wire?

Keep reading to learn more about the correct wire size for a 200-amp circuit.

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Wire Size for 200 Amp 350 Feet

If you intend to consume energy on a sub-panel that is far away, be sure to take the voltage drop into account. The voltage will decrease with distance while transferring power from the sub-panel. As a result, your wire must handle more amps in the circuit. 

According to the NEC 310-16 rule, you must roughly increase the total amps for a 200 amp aluminum or copper wire by 20% for every 100 feet of distance. You can use this rule to determine the size of a 200 amp wire for a distance of 200 feet or more. That indicates that if you have 350 feet distance, the decrease would be around 70%.

Now that you wish to transfer 200 amps. Here is a brief description of the calculation’s steps:

200A / 0.57 = 350 A. 

To account for the 80% NEC rule, multiply by 1.25, giving 438A. 

You’ll be searching for a wire that can carry 438A of current. You must cope with the extra current when you boost the amps to compensate for the voltage drop. Therefore, a larger-sized conductor wire is required to ensure safety.

Related: 50 amp wire size – Gauge, Length & Voltage

2/0 Copper Wire for 200 Amp Service

You must use 2/0 AWG copper wire to securely install a 200 amp electrical service. The ampacity of 2/0 AWG copper wire is 175A at 75 °C. These are safe options since you can use the entire electrical service without experiencing an excessive voltage drop. 

Any copper wire smaller than 2/0 AWG will result in higher voltages which may lead to melting. To avoid resistance and overheating building, using bigger wire sizes is recommended. It helps maintain the effective operation of the equipment and lengthen the connectors and wires’ lifespan. 

The finest surge protection comes from copper wiring, which also shields your electronics from faulty wiring.

Since copper wiring is often less expensive than aluminum-clad or aluminum wiring, you can pay less over time. In terms of standard installation techniques and appearance, aluminum and aluminum-clad wires closely resemble copper wiring. However, they lose more electricity over a particular wire length due to resistance. 

Therefore, most cables with a specific amperage rating will no longer be able to handle that amperage safely if you use the wire over an excessively long distance.

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Service Rating (AMPS) Copper conductor (AWG) Aluminum (AWG/KCMIL)
100 4 2
150 1 2/0
200 2/0 4/0
250 4/0 300

100 Amp Vs. 200 Amp Wire Size

A 200 amp panel is significant, while a 100 amp panel is less. A larger panel means you will have many extra spaces in your panels. 

A 200 amp panel is generally suitable for anywhere from 40 to 50 circuits. Older residences with lower electricity usage mostly use 100 AMP panels. It doesn’t necessarily indicate they are unsafe, even though they are occasionally viewed as outdated when matched to more contemporary residences with a larger capacity.

A 100 AMP panel consists of either a 20-space or 30-space panel. The amount of electricity you use will determine whether you require a 200 AMP panel or a 100 AMP panel. Households under 3,000 square feet may typically use 100 AMP as long as they don’t use electric heat or air conditioning.

200 Amp Wire Size Aluminum

You’ll need 4/0 AWG aluminum safely using a 200 amp electricity supply. Due to resistance, aluminum wires and clad lose voltage after a certain length. Therefore, providing your home with the optimum power might be challenging while preventing any harm or dangerous fires from being started by poor wiring.

Copper is less conductive than aluminum, which also reacts to corrosion and heat more quickly. You also require a thicker wire gauge to compensate for the reduced conductivity. Some electricians prefer aluminum wires. 

Copper is considered more pricey, heavy, and challenging to install, making aluminum a popular choice among electricians.

Aluminum Service Wire Pros 

  • A larger gauge but still lightweight makes it easier to install. 
  • It is also more affordable than copper wire.


  • It is corrosive. Hence, bare wiring must have an antioxidant coating to prevent fire dangers.
  • Any temperature change might cause contraction and expansion, resulting in connectivity issues that could catch fire.
  • Any terminals, lugs, screws, and connectors for particular parts must be aluminum-rated.
  • Due to corrosion or other damages, it may have to be replaced sooner than copper.

3/0 Copper Wire for 200 Amp Service

According to the NEC’s minimum specifications, a 3/0 copper conductor is typically needed for a 200-ampere feeder. A copper device grounding conductor of at least 6 AWG size is required.

Suppose the feeder ground fault conductors were to be expanded in size from 3/0 copper to 250 KCMIL copper. In that case, that’d necessitate a proportional increase in the size of the device grounding component.

Copper Wire Pros

  • Allows for thinner gauge and longer runs with minimal voltage drop
  • Lighter copper stands that are more flexible make bending simpler
  • It’s more durable to install since it’s heat and corrosion-resistant. 


  • High prices hence costlier to install 
  • It’s heavier, making installation more difficult.

200 Amp Sub-Panel Wire Size

According to the NEC 310-16 rule, you must roughly increase the number of amps for a 200 amp aluminum copper wire by 20% for every 100 feet. For instance, you may run a 200 amp connection 100 feet from the sub panel. A  circuit like this needs wires with a minimum ampacity of 250A.

Additionally, to have the proper size wire for 200 amps for that distance, you must raise the amps by 20%:

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

It’d help if you used a 300A ampacity wire or higher. The 350 KCMIL wire is ideal for 100 feet distance, 200-amp service, as seen from the KCMIL list. That is a result of its 310A ampacity.

200 Amp Wire Size Ground

A grounding system safeguards you from fatal electric shocks and fire only when correctly installed by a professional. It’s essential to use the proper size of grounding wires and size as well. A grounding wire with a 125A current rating may be a different size than one with a 100A or even 150A current rating.

The following table shows the grounding wire size requirement for a 200 Amp service:

Copper Wire Aluminum Wire

 Some of the factors to consider while purchasing a grounding are. 

  • Neutral and Hot Wires Must be Uniform.

The neutral and hot wires must have the same gauge since they must transmit the same current.   The neutral wire returns the hot wire’s current to the appliance. Thus, using identical-sized cables for the two makes it logical. 

  • Bigger Wires Are Recommended

There’s no restriction on the grounding wire’s size. A more significant ground line won’t ultimately cause any damage to your electrical system. It will increase your costs because smaller gauge wires are cheaper than higher gauge cables. 

Final Thoughts 

If you’re looking for the proper wire size, length, and voltage for a 200-amp circuit, you must consider various factors to ensure you get it right. For example, you should consider the distance between the source and the appliance you want to power. Your wire choice should account for the voltage drop over a distance.

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