70, 80, 100, 125, 150, 200, 400, 600 Amp Wire Size Chart

Knowing which size to pick is important, so you can use the right one for your equipment that requires electricity. If this is your first time reading about the topic, we cover some basic things to know about it.

Summary: Buying recommendations

What electrical components do I need for a project? The rule of thumb that techs will usually go by is that for a 70 amp circuit breaker, 4-gauge copper wire is the right size to go with. For an 80 amp, you need a 4-gauge copper wire size. For a 100 amp service, you will need a 1-gauge wire size.

For 125 amps, you will need a 1-gauge copper wire size. For 150 amp, you will need a 1/0-size copper wire size. For a 200 amp service, you will need a 250 kcmil-gauge copper wire size. For a 400 amp service, you will need a 600 kcmil-gauge copper wire size. For 600 amp, you will need a 1500 kcmil-gauge wire size.

We’ve got you covered if you want to buy a circuit breaker or a sub-panel. Here are all the products we recommend based on NEC’s ampacity chart to ensure safety.

[rtbs name=”gauge-2″]

Table of Contents

circuit breaker

60 amp

As you can see, you will want a 6 gauge wire for 60 amp. If you’re more cautious, a 4 AWG is great. That is assuming the right conditions, such as temperature.

Let’s say you have an 8-gauge and a 10-rated lying around at home. You want to know if you can use these with the circuit breaker. The 8-gauge nor the 10-gauge can be coupled with this breaker. Simply take a look at the chart further down the page.

70 amp

For 70 amps, the right wire size is either a gauge 3 aluminum or a gauge 4 copper. That is, assuming there aren’t other factors impacting the performance.

The requirement depends on whether aluminum or copper is used and the ambient temperature. For a circuit breaker with this rating, you can use 4-gauge copper at an ambient temperature of 140°F.

Pros

  • We love getting deliveries from WindyNation.
  • The options go up to 100′.
  • It was received as we had hoped.

Cons

  • This product is only 25′ long.
WindyNation
You can trust WindyNation.

80 amp

The right 80 amp wire size is a gauge 4 copper wire. 80 amp service will need to be a 2 AWG if you are going for aluminum instead. Be sure you get the right one for your subpanel and breaker!

Pros

  • Here’s another option from WindyNation.
  • You can upgrade to 100′ length instead.
  • We love that it’s made in the US.
  • No one complains about receiving less than they ordered.

Cons

  • It’s only 10′ long.
WindyNation
It's 10 feet.

100 amp

The right 100 amp wire size is a 1-gauge. However, that is only if you don’t consider the material. We’ll go into a little bit more detail below.

You need to get a gauge 1 made of aluminum for a sub-panel, whereas a 3 will work if it is copper. It applies to both a breaker & sub-panel. These recommendations are based on conductor size temperature ratings of 167°F. 

Be sure to consider the table below to see the various products we recommend for sub-panels and entrance cables. When you click on the table, you may have to make the right selection to follow the electrical recommendations provided.

Pros

  • WindyNation is great.

Cons

  • It’s only 10′ long.
  • You’re suddenly paying a lot of money if you want a 100′ option.
WindyNation
Another option from WindyNation.

125 amp

The right wire size for 125 amp service is a gauge 1 copper or a 2/0 aluminum to be on the safe side. Look at the table below to see the sub panel and breaker we recommend for 125 amps of service.

Name1/0 AWG
CompanyWindyNation
FeatureFlexible Cable
Item Weight‎9.94 pounds
Length25′ – 100′

Pros

  • It does what it’s supposed to.
  • Delivery was smooth.

Cons

  • 1/0 AWG is expensive.
  • The shown product is only 25′.
  • The chosen product surprisingly had no reviews at the time we bought it.
WindyNation
It's 25 feet.

150 amp

For 150 amp, you need a 3/0 wire size made of aluminum. Otherwise, a 1/0 is the smallest you can go with when looking at copper.

Suppose you have a circuit breaker at home with this rating, and you would like to use it.

You will need 1/0-gauge copper at an ambient temperature of 167°F or 2/0-gaugaluminum at an ambient temperature of 194°F.

200 amp

The right 200 amp wire size is 250 made of aluminum or a 3/0 made of copper. Here’s a table with the different sub-panel and breakers we recommend for this power level.

Pros

  • It arrived as intended.
  • No complaints about the product we received.
  • The price was fair, everything considered.

Cons

  • It’s not always available for purchase on Amazon.
  • Alternatives are hard to find on Amazon.
Nassau Electrical Supply
It's thick cable.

300 amp

For 300 amp service, you will want copper wire size 500 kcmil to handle the load.

400 amp

The right 400 amp wire size requires an aluminum wire size of 1000 kcmil. In contrast, a copper 600 kcmil can handle that amount of power. Take a look at the NEC electrical cable chart below.

600 amp

The right wire size for 600 amp service is at least 1500 kcmil assuming a temperature of 167°F for the conductor.

Full wire size chart

Check the chart below to find the right wire size for 70 or 80 amps. We have the right wire size for you if you need something more substantial, like 100, 125, or 150 amps. Scroll down further if you need the wire size for 200, 300, 400, or 600 amps.

 Max amp forAluminumMax amp forCopper Our recommendation
WirGauge167°F194°F140°F167°F194°F 
1420202520
12202525253020
10303530354030
8404540505540
6506055657550
4657570859565
375858510011075
2901009511513090
1100115110130145100
1/0120135125150170120
2/0135150145175195135
3/0155175165200225155
4/0180205195230260180
250205230215255290205
300230255240285320230
350250280260310350250
500310350320380430310
600340385355420475340
750385435400475535385
1000445500455545615445
1250485545545590665405
1500520585585625705435
1750545615615650735455
2000560630630665750470

What is a gauge?

The gauge is the diameter of the product. This determines how much electrical current it can safely carry. If you have ever been to the electrical section of a hardware store, you will notice it comes in several options.

extension cord

Instead of referring to its actual thickness, people use its gauge. 6 and 4 are just some of the numbers you’ll encounter. You could also come across gauges like 1/0, 2/0, and 3/0.

It is inversely proportional to the diameter. It means the higher the number, the smaller the diameter. If it is not written on the product itself or is unclear, you can use a thickness tool to determine it. Getting the right diameter is important because it determines the maximum current it can safely handle. Using an incorrect one could lead to serious problems in the long run. So before deciding which to buy, consider how much electrical current it can handle by identifying the devices you will use.

The United States and 65 other countries use the AWG as the unit of measure. Other countries use the Imperial Standard, defined by the British Board of Trade.

Make sure to read two of our other resources on Thermo King alarm codes and an in-depth look at welding gas or welding glasses.

Choosing the right one

truck transporting wire

They usually burn if you use the incorrect one. It is advisable to know the correct one to prevent this from happening. The bad thing is that most people are not aware that your choice makes a difference. People often make the connections themselves without consulting or calling a licensed electrician. It could lead to serious issues when done incorrectly. He’ll have all the necessary information and be able to pull the necessary permits. There are many reasons and situations where you want to hire a pro.

They have all their information in order and know everything there is to know about wiring size requirements and breaker amps. For instance, would you have thought about the importance of a grounding electrode, and do you know what romex wire is?

When the setup involves the circuit breaker, you should take extra precautions. Installing the right components will greatly prevent common issues from happening. In most cases, issues arise because of an incorrect one. The different electrical components always need to be compatible with one another.

If you have a 60 amp circuit breaker for your water heater, read the next section as we guide you to understand the basics. We’ll ensure you know which products go with your clothes dryer or air conditioner.

electrical tools

What happens when you choose the wrong one

It is a common misconception for people to think that as long as the ends of the wire fit a connector, there will be no issues. It is not the case for circuit breakers. People unaware of their importance often use too small gauges to connect their circuit breakers. Smaller diameter ones are cheaper than the bigger ones. Unaware people often go for the cheaper ones, thinking it will not make any difference. Sadly, it will only cost them more in the long run.

Using a larger one for your circuit breaker is often the best way to go. The only negative effect this has is your budget, which will cost you more upfront. When picking a larger one, you spend more than what you may need. However, it will not cause any damage to your circuit breaker. Instead, it can better handle the electrical current flowing through it.

When you’re going with a copper or aluminum wire longer than 100 ft, you’ll want to make sure to consider the voltage drop.

subpanel

But if you find yourself having the incorrect one, here are the things that might happen.

Consequences
Drop-in performanceMelted insulation
FireDamaged equipment

A drop in performance

If you connect appliances to a circuit breaker using too small one, achieving peak efficiency may be impossible. The appliances can only receive a part of the energy required to operate at peak performance. In effect, your appliances will be unlikely to achieve their optimal performance.

two subpanels

You may have a 15 amp circuit breaker that you need to use for light fixtures at home. At best, using anything less than the recommended 14-gauge could lead to performance issues. For electric furnaces, you need at least a 4 because of the amount of current they consume.

Make sure to see what the requirement are, whether you are welding or powering a metal lathe. If not, you might be using the wrong cord. It could lead to suboptimal performance, at best.

It can start a fire

Incorrect wire size and amp rating causing burning wire

Fire is the worst-case caused by a burning electrical component that starts. Although modern circuit breakers have safety measures, they may not be enough if the load is too much.

A common safety measure for modern circuit breakers is the trip mechanism. When the circuit breaker experiences an overload, it will trip to cut the current from passing through. It helps prevent any damage from happening. However, having a trip mechanism does not fully prevent a fire from happening.

Melted insulation

smaller diameter can handle less current, making them more resistant to energy flow. If the diameter is way smaller for your circuit breaker, the current flowing is more than it can handle. Due to high resistance, heat generates and will eventually lead to melting.

Damage to the equipment

Aside from performance drop issues and the possibility of starting a fire, using a smaller one may damage your equipment. When the power supply is not stable, it may bust your equipment.

Standard wire gauge chart

lawn mower cord

You should know that it is important to have a licensed electrician handle any electrical work. It helps to know some basic electrical things, such as the right gauge. The chart electricians use as their reference will differ depending on the region.

Using a standard measurement instrument is easy to answer your questions about the product’s diameter. We use the AWG system in the United States to determine it. The AWG defines the diameter of solid round wires, otherwise known as the gauge. Given the various conditions, the capacity is the highest current it can handle. The material it was made from, and the ambient temperature is important factors.

When referring to the table below, note that the AWG value is opposite to the diameter. A higher AWG refers to a smaller diameter. It means an 8-gauge can support a higher capacity than a 10. The chart below defines the diameter in inches and millimeters. The chart should help determine which one to choose.

The one with the largest diameter is the 0000, while the smallest is the 40. The former lets more energy flow through it at any given time than the smaller ones will.

Standard wire gauge chart

Frequently Asked Questions

Let us look at other queries and questions that commonly pop up in electrical work.

bathroom being installed

Wire versus Cable

Both of the above terms may seem interchangeable to many folks, but few know the significance of each. The basic wire is one conductor, whereas a cable has many different conductors grouped. An outer layer of the sheath protects the cables. The wire usually goes bare or has a PVC coating on top to protect and prevent accidents.

The wire unit is the gauge or thickness we have referred to above. In the case of the cable, the measuring unit is the total number of wires a cable consists of and their thickness.

Wires carry small electrical loads and transmit telecommunication signals and other small parts like bulbs and vehicle parts. On the other hand, the cables transport huge loads of electrical currents.

The cable types include coaxial cable and twisted pair cable. It can also include multi-conductor cable and fiber-optic cable. A multi-conductor table means joining many different cables. Its goal is to reduce noise and cross-talk. Coaxial cables consist of two conductors running parallel to them, one inside and one outside. These are generally used in televisions. You’ll generally find the twisted pair type wherever data and telecommunication transportation is required. Since the twisting of the two conductors reduces noise, it is perfect for transmitting data signals through long distances.

electrician installing an outlet

Is it ‘Gauge’ or ‘AWG’?

American Wire Gauge is often referred to as AWG. It is the standard used in most of North America and refers to thickness. It is used to denote the current carrying capacity of the wire and the cross-sectional area. Using this standard means you can purchase a 14 AWG wire from two different vendors. You will find they are the same thickness. The ‘gauge’ can be used as a shortened way of expressing AWG, but the seller must always confirm this. Sometimes manufacturers use the term ‘gauge’ to market cables that are certainly not in AWG units.

What is a breaker box/sub-panel? What is the difference between a Main Panel and Sub-panel?

The main panel is also known as the service entrance panel. Here the power company’s current first enters the home and is further distributed to the rest of the household. It’s also the first safety net that protects your home from any kind of electrical damage or fires. Suppose you suspect any faults in the circuit. You can directly switch off the main panel and take your home out of the power grid of the electricity supplier.

wire spool and subpanel

The sub-panel is like a miniature main panel that doesn’t have a direct connection to the power utility company. It feeds off the main panel’s current. Its purpose is quite similar to the main panels in that it protects appliances from shorting or faulting. They also contain circuit breakers and fuses to detect any electricity surcharge and immediately stop the current to avoid fires. But then how are sub-panels different?

Sub-panels are different as they take their power from the main panel. Their main purpose is to help you organize your home’s electrical circuit in a manageable manner. You could also use a sub-panel to avoid overcrowding in the main panel. Overloading is a serious fire hazard. You can avoid this by distributing your home into the area, each having its sub-panel.

electrician working

Subpanels can also isolate certain areas that have different power usage. For instance, a garage workshop will put a great load on the main panel with its heavy machinery. You can avoid this by setting up a separate sub-panel for the garage. You can isolate the area with the problem and turn off the respective area’s sub-panel in any short or fault. At the same time, the rest of the house can remain powered as usual.

lawn mower extension cord

What is the National Electrical Code?

The NEC is used as a benchmark for safe electrical installation and inspection in all 50 United States of America. It is part of the publication by the National Fire Protection Association. Although it is not established by federal law, all states commonly follow it.

electrician installing 200 amp wire

Basic NEC rules and Codes

  • Size of circuit breaker: For non-motor loads, the maximum loading for a breaker is cut off at 80%. Under no circumstances can the breaker be larger than the ampacity unless it is for motor loads.
  • General design guidelines: lights and outlets should be set up on different circuits. This will allow maximum loading on light circuits and leave capacity for other outlets.
  • Outlets circuits must have GFI protection if located in residential locations. Any place with portable equipment and machinery must also have GFI outlets. This includes any garage areas and workshops. It can also include shops and warehouses. Each piece of fixed machinery like drill presses or welding machines must also have its GFI-protected circuit.
  • Service size: The minimum service for a very small building is 100 A and 20 circuits. It is advisable to do load calculations for larger places.
  • Underground – Use XLP-USE for underground wiring, with AWG copper minimum.
  • Protecting cables and conduits: Conductors must be inside a cord or trench. They can also be inside a raceway or cable tray.
  • Outdoor receptacle: Each home must have one front and one rear receptacle, which is easily accessible. It is advised it should be located no more than 6 and a half feet above the ground.
  • Receptacles used to supply power to the pumps and motors of spas and pools must be at least 10ft away from the pool if without GFCI. If the receptacle is GFCI protected, it can be located no closer than 6ft.
  • Light fixtures located outdoors do not require GFCI protection.
  • Low voltage light fixtures should not be any nearer than 5ft to indoor water structures like spas and pools.
  • Telephone and other types of wiring should be located at least 10ft away from the top of the water surface of indoor water structures.
  • Underground wiring must be covered with conduit.
  • Buried underground or exposed wiring must always be listed for its use. UF cable type is best known for underground purposes as it can be dug and settled underground without the use of a conduit.
  • Wiring carrying equal to or less than 30 volts must be located 6 inches deep underground.
wires

There’s so much information when it comes to electricity, including grounding rods, materials, & branch circuits. We hope this post has helped you learn a thing or two. Here’s a variety of questions we get asked a lot that could help you get started on your DIY project, if you’re doing the job yourself. Make sure you get the conductor sizing right, whether it’s 4/0 aluminum wire or 3/0 copper wire.

outdoor cord on the floor

It is an essential skill if you’re just getting into electrical wiring and systems know-how. Now you know the basic steps to reading an online wire size chart.

Read a wire size chart using the above values.

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