Bare copper wire is copper conductor with no insulation or jacket, used mainly for grounding, bonding, and other jobs where exposed metal contact is intended — not for hot or neutral power wiring.
A copper wire with no jacket shows every scratch, every nick, every spot of corrosion the moment it happens. That is the point. Utilities and electricians run bare copper where visible condition matters more than protection, and where the metal is supposed to touch earth, metal conduit, or a ground rod directly.
This is a narrow-purpose material. It is not a substitute for insulated wire, and treating it like one is where people get themselves into trouble with inspectors and with their own safety.
What Is Bare Copper Wire Made Of?
Bare copper wire is a solid or stranded copper conductor with no PVC, XLPE, rubber, or thermoplastic jacket over it. The copper is the insulation-free element — the conductive path itself.
Two form factors cover nearly every real application. Solid bare copper is one continuous copper strand and is used for straight runs where flexibility isn’t needed. Stranded bare copper is multiple copper strands twisted together and is used where the wire has to bend around corners, route through tight spaces, or take vibration.
A related variant, tinned bare copper, has a thin metal coating over the copper. That coating is not insulation — the conductor is still classified as bare.
Insulated wire differs on every count. It carries a jacket that provides shock protection, abrasion resistance, and color coding, usually green or green-and-yellow when the wire is a grounding conductor.
What Is Bare Copper Wire Used For?
Bare copper wire is used for grounding electrode conductors, equipment grounding conductors, bonding jumpers, grounding grids, and lightning-related bonding where direct metal-to-metal or metal-to-earth contact is intended.
Grounding applications account for the overwhelming share of bare copper in the field. In these systems, low impedance and easy visual inspection matter more than a protective jacket, and bare copper delivers both. Monroe Engineering notes that bare copper is commonly selected where direct earth contact and a low-impedance fault-current path are required.
Bare copper is also permitted as an equipment grounding conductor and as a grounding electrode conductor under NEC-based guidance, with bare listed as an acceptable identification method for EGCs and explicitly permitted for GECs.
Bare copper is generally not used as a hot or neutral conductor. Insulated wire is required for general branch-circuit wiring, and bare copper should not be assumed acceptable in those roles.
If you’re sourcing the material for a grounding or bonding project, this roundup of tested bare copper wire options covers gauges and form factors.
| Property | Bare Copper Wire | Insulated Wire |
|---|---|---|
| Jacket | None | PVC, XLPE, rubber, or thermoplastic |
| Typical role | Grounding, bonding, earthing grids | Hot, neutral, branch-circuit power |
| Shock protection | None from the wire itself | Provided by the insulation |
| Color coding | Not applicable | Often green or green/yellow for grounds |
| Damage visibility | Immediate — copper is exposed | Hidden under the jacket |
| Moisture and abrasion resistance | None beyond the copper itself | Added by the insulation |
| Direct earth contact | Permitted where local code allows | Usually avoided for raw earth contact |
Does Bare Copper Wire Need Physical Protection?
Yes — bare copper grounding conductors still require physical protection in some routes. A bare copper grounding electrode conductor smaller than 6 AWG, or any grounding conductor subject to physical damage, must be protected in a raceway or enclosure under NEC-based guidance.
Local codes govern when bare conductors are permitted in concrete, masonry, soil, panels, and similar environments, so the installed location decides whether a raceway is required.
Insulated grounding conductors are often preferred when identification, separation, or extra protection is needed. Electro Specialties’ grounding specification calls out copper-only grounding conductors for direct contact with earth or building materials, a reminder that the bare-versus-insulated decision follows the environment.
Solid vs. Stranded Bare Copper: Which Fits Your Job?
Solid bare copper fits simple straight runs, while stranded bare copper fits bends, vibration, and direct-burial or utility-style applications.
Grounding articles and specs commonly reference stranded bare copper for grounding and bonding work. One specification document reviewed lists grounding wire sizes such as No. 4 or No. 6 AWG copper for bonding conductors, and 28 kcmil / 14 strands of No. 17 AWG copper for bonding cable.
Match the form factor to the route. If the wire has to snake through a panel or follow a curved conduit, stranded wins. If it runs in a straight line from point to point, solid is fine.
Check your local code before installation either way — it takes precedence over any general guidance on when bare copper is permitted.
FAQs
Can you use bare copper wire for outlets or light switches?
No. Bare copper is not an acceptable hot or neutral conductor for branch circuits. It is permitted as a grounding conductor, where it connects equipment or a grounding electrode to earth. For the current-carrying conductors feeding outlets and switches, insulated wire is required by code.
Is bare copper wire safe outdoors or buried in soil?
Bare copper is used in direct-earth applications where local code allows it. Grounding electrode conductors and grounding grids are common examples. Copper-only grounding conductors are specifically called out for direct contact with earth or building materials in at least one grounding specification.
Why is grounding wire often green if bare copper works?
Green or green-and-yellow insulation marks a grounding conductor for identification and adds protection against moisture and mechanical wear. Bare copper is accepted for grounding in many cases, but insulated grounding wire is often preferred where separation from other conductors or extra durability matters.
References & Sources
- Monroe Engineering. “What Is Bare Copper Wire?” Defines bare copper wire and its grounding and bonding applications.
- Electro Specialties. “Grounding Specification.” Covers grounding conductor materials, sizes, and direct-earth contact.
- Helukabel. “Earthing Cables.” Describes earthing and grounding conductor types and identification.
