1/4″ x 3″ Copper Flat Bar (C110) – High Conductivity Copper Strip

Copper Flat Bar (C110) – High-Conductivity Copper Strip

Our copper flat bar, also called copper strip or copper busbar, is made from C110 (C11000 / ETP) copper with a minimum copper content of 99.9% and conductivity of 100% IACS. Its rectangular cross-section provides a large surface area for carrying current and dissipating heat, which is why flat copper is the standard material for busbars, grounding straps and power connections in electrical systems of every size.

The bar is smooth, straight and easy to work. It can be cut, punched, drilled, bent on edge or on the flat, and soldered or brazed, so it fits comfortably into panel building, switchboard assembly, DIY electrical projects and metal fabrication. Each listing in this category represents a specific thickness, width and cut length, so you can order precisely the size your design calls for.

Key Features and Benefits

• Rectangular copper bar in C110 / ETP grade, minimum 99.9% copper.
• Very high electrical conductivity (100% IACS minimum) for efficient current carrying.
• Large, flat contact surfaces for secure bolted connections and good heat dissipation.
• Excellent formability: can be bent, punched, drilled and shaped with standard workshop tools.
• Good corrosion resistance; the surface can be tinned, silver-plated or left bare.
• Readily solderable and brazeable for permanent joints.
• Wide range of thicknesses, widths and lengths to match your current-capacity and space requirements.

Typical Properties of Copper C11000 (ETP)

• Copper content: 99.90% minimum (including silver), with a small controlled oxygen content of about 0.02–0.04%.
• Electrical conductivity: 100% IACS minimum in the annealed condition – the international benchmark for electrical-grade copper.
• Thermal conductivity: approximately 391 W/m·K at room temperature.
• Density: approximately 8.89 g/cm³ (0.321 lb/in³).
• Melting point: approximately 1,083 °C (1,981 °F).
• Corrosion resistance: excellent resistance to atmospheric exposure, fresh water and many non-oxidizing chemical environments.
• Related designations: C11000, Alloy 110, ETP (Electrolytic Tough Pitch) copper, Cu-ETP / CW004A, UNS C11000.

Common Applications

• Busbars and power distribution: switchboards, control panels, battery connections, inverters and distribution cabinets.
• Grounding and bonding: earthing straps, ground bars, lightning-protection systems and equipotential bonding.
• Industrial electrical equipment: transformers, motors, generators, welding equipment and furnaces.
• Renewable energy and EV systems: battery interconnects, solar installations and charging equipment.
• Thermal applications: heat spreaders, heat sinks and conductive thermal bridges.
• Fabrication and decoration: architectural trim, custom brackets, craft projects and restoration work.

Choosing the Right Size

The current-carrying capacity of a copper busbar depends mainly on its cross-sectional area, the ambient temperature, the allowed temperature rise, how the bar is mounted and whether it is enclosed. Thicker and wider bars carry more current and run cooler. When bending flat bar, use a gradual radius and avoid sharp kinks to prevent cracking; bending on the flat is generally easier than bending on edge. For bolted joints, drill clean holes, remove burrs and keep the contact surfaces clean and flat. Always consult a qualified electrician or engineer when sizing busbars for a specific load.

Cutting, Handling and Ordering Notes

Dimensions are nominal and listed in inches. As with all drawn and rolled copper products, small dimensional tolerances apply, and the surface of the metal naturally develops a darker oxide patina over time without affecting performance. Wear gloves when handling to keep the surface clean, store the material in a dry place, and keep it separated from steel and other dissimilar metals during storage to avoid surface staining. If you need a quantity, length or size that is not listed, please contact us and we will be glad to help.