Copper Clad Aluminium (CCA) Wire
Copper clad aluminium wire is an aluminium core with a metallurgically bonded copper skin, typically 10 % or 15 % copper by volume. It weighs about 40 % as much as copper wire of the same diameter, keeps a solderable copper surface, and at radio frequencies carries current almost entirely in the copper layer. Metline supplies CCA wire in hard and annealed classes for coaxial cable, braiding and winding wire to cable makers worldwide.
- Copper content
- 10 %, 15 % (20 % CCAM)
- Classes
- A (annealed), H (hard)
- Diameter
- about 0.08 – 8 mm
- Standard
- ASTM B566
What CCA wire is and why it is used
CCA wire is made by bonding a copper sheath to an aluminium rod and drawing the composite down to wire size. The common route wraps copper tape around a clean aluminium rod, seam-welds it and then draws the bimetal through successive dies, so the copper and aluminium deform together and stay bonded. The copper fraction is fixed by volume and stays the same at every diameter.
The result combines properties of both metals. The aluminium core keeps weight and metal cost low. The copper surface gives good contact resistance, can be soldered and crimped like copper, resists oxidation better than bare aluminium, and dominates conduction at high frequency because of the skin effect.
CCA is not a replacement for copper everywhere. Its DC resistance is about 1.5 times that of copper at equal diameter, it is weaker and less fatigue-resistant than copper, and the aluminium core can corrode if exposed at a cut end in damp conditions. It is chosen where its weight, cost or high-frequency behaviour gives a clear benefit.
CCA wire types and specification
| Type | Description | Copper by volume |
|---|---|---|
| CCA 10A / 10H | Copper clad aluminium, annealed / hard drawn | about 10 % (8 – 12 %) |
| CCA 15A / 15H | Copper clad aluminium, annealed / hard drawn | about 15 % (13 – 17 %) |
| CCAM (CCAA) 10A, 15A, 20A | Copper clad aluminium-magnesium alloy core, higher strength for fine wire | 10, 15 or 20 % |
| Tinned CCAM (CCAAT) | CCAM with a tin coating for solderability and corrosion protection | 10, 15 or 20 % |
Specification summary
- Cladding
- Electrolytic copper (Cu-ETP / C11000)
- Core
- Electrical aluminium such as 1060 or 1350; Al-Mg alloy for CCAM
- Temper
- Hard (H) or annealed (A)
- Diameter
- About 0.08 – 8.25 mm
- Packing
- Spools, reels or coils
- Standards
- ASTM B566; SJ/T 11223 used for CCA and CCAM in some markets
Copper thickness and volume ratio
Specifications control both the average copper fraction and the thinnest point of the copper layer, expressed as a percentage of wire diameter (d). The thinnest-point rule matters because a thin spot exposes aluminium during stripping or crimping.
| Type | Class | Copper at thinnest point | Copper volume ratio |
|---|---|---|---|
| CCA | 10A, 10H | ≥ 1.75 % of d | 8 – 12 % |
| CCA | 15A, 15H | ≥ 2.50 % of d | 13 – 17 % |
| CCAM / CCAM tinned | 10A | ≥ 2.00 % of d | 10 – 12 % |
| CCAM / CCAM tinned | 15A | ≥ 3.25 % of d | 15 – 17 % |
| CCAM / CCAM tinned | 20A | ≥ 4.50 % of d | 20 – 22 % |
A worked example: a 1.0 mm CCA 10 % wire has a copper layer about 26 µm thick. The skin depth in copper is about 21 µm at 10 MHz and under 7 µm at 100 MHz, so at cable-TV and broadband frequencies practically all the current flows in copper. That is why CCA performs almost like solid copper as a coaxial centre conductor.
Resistivity, density and mechanical properties
| Type | Class | Max resistivity at 20 °C (Ω·mm²/m) | Approx. conductivity (% IACS) | Density (g/cm³) |
|---|---|---|---|---|
| CCA | 10A, 10H | 0.02743 | ≈ 62.9 | 3.32 (±3 %) |
| CCA | 15A, 15H | 0.02676 | ≈ 64.4 | 3.63 (±3 %) |
| CCAM | 10A / 15A / 20A | 0.0279 / 0.0270 / 0.0262 | ≈ 61.8 / 63.9 / 65.8 | 3.32 / 3.63 / 3.94 |
| CCAM tinned | 10A / 15A / 20A | 0.0284 / 0.0275 / 0.0267 | ≈ 60.7 / 62.7 / 64.6 | 3.32 / 3.63 / 3.94 |
| Copper, annealed (reference) | — | 0.01724 | 100 | 8.89 |
| Aluminium 1350 (reference) | — | 0.0282 | ≈ 61 | 2.70 |
Density follows directly from the copper fraction: 10 % copper gives about 3.32 g/cm³ and 15 % about 3.63 g/cm³, against 8.89 g/cm³ for copper. A kilogram of CCA 10 % therefore contains about 2.7 times the length of a kilogram of copper wire of the same diameter.
| Diameter (mm) | Tensile, class H min (MPa) | Tensile, class A min (MPa) | Elongation, class H min (%) | Elongation, class A min (%) |
|---|---|---|---|---|
| 0.080 – 0.120 | 205 | 172 | 1.0 | 5 |
| 0.121 – 0.360 | 207 | 172 | 1.0 | 5 |
| 0.361 – 0.574 | 207 | 172 | 1.0 | 10 |
| 0.575 – 2.05 | 207 | 138 | 1.0 | 10 – 15 |
| 2.06 – 3.67 | 200 – 172 | 138 | 1.0 | 15 |
| 3.68 – 5.19 | 166 – 152 | 138 | 1.5 | 15 |
| 5.20 – 8.25 | 138 – 110 | 138 | 1.5 | 15 |
Mechanical limits are summarised by diameter band; within a band the hard-drawn minimum falls as diameter increases. Confirm the exact table of the specification on your order.
CCA compared with copper and aluminium wire
| Property | Copper | CCA 10 % | Aluminium 1350 |
|---|---|---|---|
| DC resistance, same diameter | 1.0 × | about 1.55 – 1.6 × | about 1.64 × |
| Weight, same diameter | 1.0 × | about 0.37 × | about 0.30 × |
| Surface for joining | Copper | Copper | Aluminium (oxide) |
| Solderable | Yes | Yes | Not with standard methods |
| High-frequency performance | Reference | Close to copper above about 5 – 10 MHz | Lower |
| Flex and fatigue life | Best | Lower than copper | Lowest |
For DC and power-frequency use, CCA needs a larger diameter than copper for the same resistance, which offsets part of its weight advantage. For RF and high-frequency winding wire the trade-off is far better, because the copper skin carries the current.
Where CCA wire is used, and where it is not
- Coaxial cable: centre conductors of CATV, satellite and antenna cables
- Braided shields: CCA braid gives a solderable, light shield
- Magnet and winding wire: enamelled CCA for loudspeaker voice coils, small motors, transformers and induction coils where low mass matters
- Audio and video cables: signal conductors where weight and cost are priorities
- Automotive and aerospace harnesses: selected signal and light-duty circuits
- RF and high-frequency conductors: where skin effect concentrates current in the copper layer
Drawing, enamelling and termination
CCA rod and wire can be drawn further on standard copper drawing lines with die sequences adjusted for the softer core, and annealed in-line. Enamelling and tinning lines handle CCA much like copper wire, which is why it substitutes easily in winding wire production.
For termination, crimp terminals rated for CCA or for aluminium conductors are preferred; soldering works on the copper surface but heavy heat can soften the core. Seal cut ends in damp locations so the aluminium core is not exposed to moisture. Store spools dry, because condensation on the copper surface causes tarnish that complicates enamelling and soldering.
How to order
- SpecifyType and copper percentage, class (A or H), diameter and tolerance, coating, spool type and net weight per spool.
- ConfirmWe confirm resistivity, mechanical limits, certification and delivery terms (EXW, FOB, CIF or DAP).
- InspectDiameter, copper ratio, resistivity, tensile and elongation reported on the certificate.
- ShipSpools in cartons or pallets, wrapped against moisture.
References and standards
- ASTM B566 – Standard Specification for Copper-Clad Aluminum Wire
- SJ/T 11223 – Copper clad aluminium wire (industry standard)
- ASTM B230 – Aluminum 1350-H19 Wire for Electrical Purposes
- ANSI/TIA-568 – Commercial Building Telecommunications Cabling Standard
Copper clad aluminium (aluminum) wire: FAQ
What does 10 % or 15 % mean for CCA wire?
It is the copper share of the cross-section by volume. CCA 10 % has a thinner copper layer and is lighter; CCA 15 % has a thicker layer, slightly lower resistivity and better tolerance to stripping and crimping.
What is the difference between class A and class H?
Class A is annealed: softer, with higher elongation, for winding and stranding. Class H is hard drawn: stronger, for coaxial centre conductors and applications needing stiffness.
How much lighter is CCA than copper?
CCA 10 % has a density of about 3.32 g/cm³ against 8.89 g/cm³ for copper, so it is about 37 % of the weight at the same diameter, giving roughly 2.7 times the length per kilogram.
Can CCA wire be soldered?
Yes. The copper surface solders with normal fluxes and alloys. Avoid prolonged heat, which can soften the aluminium core, and seal cut ends in humid locations.
Is CCA suitable for Ethernet or building wiring?
Generally no. Data-cabling standards specify copper conductors, and CCA has higher resistance that causes heating under Power over Ethernet. Building wiring codes usually require copper or approved aluminium conductors.
What is CCAM wire?
CCAM (also written CCAA) uses an aluminium-magnesium alloy core under the copper. The alloy core is stronger, which suits very fine wire for braids and high-speed drawing.
Sourcing CCA wire?
Send your type, copper ratio, class, diameter and spool requirements. We will reply with availability, certification and a delivered price.
