3 Types of Copper Grounding Wire Explained

Rolls of copper wire.

Copper grounding wire is commonly found in electrical components because of its durability and conductivity. Compared to other metal conductors, it is also pretty affordable. Since electricity is so powerful, it is vitally important to use durable wires. There are a variety of different copper wires available. Three of these wires are described here.

1. Bare Copper

Bare copper is one of the more common types of copper wire that is used for grounding. Bare copper is sometimes just called grounding wire. This type of copper wire is not covered in any type of protective coating, making it completely unprotected, hence the name. This type of copper is generally used in residential homes and probably has the best conductive properties, without being protected by insulation.

Bare copper is also used as the base for most types of wire and cable. This enables these wires and cables to have grounding wires within them. Contractors like the bare copper this way because that means if it is outdoors, the bare copper is protected from the elements.

2. Green 6 THHN

Another specific type of copper wire that is used for outdoor grounding would be the Green 6 THHN wire. The green represents the fact that it is an outdoor grounding wire. This particular copper grounding wire is insulated and can be used outdoors without there being any concerns about moisture getting to the copper wire itself. Not only can this wire be considered a ground wire outdoors, but it can also serve as a conductor.

3. Gauged Copper

A close up of copper wire.

Gauged copper grounding wires vary in size. You can find them in 1/0, 2, 4, 8, 10, 12, 14 and 16 gauge. The larger the gauge number, the smaller the wire actually is. The more current you need for something, the bigger the ground copper wire must be.

  • 16 gauge is generally used for home circuits because the maximum amps allowed for any current in a home is 15 amps. So the 16 gauge wire is perfect for grounding.
  • 14 gauge is generally used for circuits that have a maximum of 25 amps going through circuits.
  • 20 amp breakers tend to need the 12 gauge copper wire for grounding. For example, GFCI outlets should use 12 gauge.
  • 10 gauge is generally used for appliances that produce 30 amps such as your washer and dryer.
  • 8 gauge is commonly used for large appliances that put out a maximum of 40 amps of circuit power.
  • 4, 2 and 1 are mostly used in the industries when dealing with large industrial types of equipment exceeding 70 amps.

Copper Grounding Wire FAQ

What kind of copper wire to use for grounding?

Bare copper wiring is the most common type used for residential grounding wire. Because it is not insulated, this wire has good conductive properties.

What is the difference between bare copper wire and green wire?

Green wires and copper wires are both used for grounding. Green wire is more often where slower conductivity is needed.

What's the difference between #1 and #2 copper wire?

Copper at scrap yards is often classified as #1 or #2. The #1 wire is clean and uncoated and usually, at least 1/16th of the inch in diameter.

The #2 copper still has a coating on it and it may also have paint or solder on it, as this is uncleaned scrap metal wire. This wire is also thinner in diameter than #1 copper wire.

Which is better stranded or solid copper wire?

Stranded copper wire is made up of small pieces of wire twisted together, while solid copper wire is a solid, one-piece wire. Because of this composition, solid wire is stronger.

Does ground wire have to be buried?

Ground wire is buried for safety reasons, because this is a live wire and electricity does travel through it. Usually, but not always, the burial and burial depth of these wires is regulated by state, city, or county building codes.

Check with the local permit office in your area to find out about specific requirements regarding ground wires.