Copper use per kilometre
Evaluate the amount of copper in an accepted screen design, rather than comparing only the purchase price of one kilogram of wire. A lower copper fraction does not, by itself, establish a lower cost for the complete cable.
APPLICATION ENGINEERING · MEDIUM-VOLTAGE CABLES
Copper-Clad Aluminum Screen Wire for Medium-Voltage Cables
Evaluate copper use and screen-wire mass against the requirements of your cable design.
Raytron develops copper-clad aluminum and copper-clad aluminum-alloy wire for project-specific evaluation in metallic wire screens. The starting point is your existing screen construction: its resistance, fault-current duty, wire dimensions, processing conditions and termination requirements—not a same-diameter substitution claim.
- At a glance
- Bare round wire · CCA and alloy-core options · Copper content stated by volume · Qualification against your cable specification
This page concerns metallic screen-wire materials. It does not approve their use as phase conductors or certify a finished medium-voltage cable.
Cable construction shown
- 1 Phase conductor
- 2 Conductor semiconductive screen
- 3 Insulation
- 4 Insulation semiconductive screen
- 5 Metallic wire screen — application discussed here
- 6 Outer sheath
Where the Wire Is Used
The metallic wire screen is positioned outside the insulation-screen system and beneath the outer cable protection in the illustrated construction. It forms part of the electrical screening and bonding arrangement of the cable. Depending on system design, it can also be required to carry fault current.
Raytron's material is the individual wire used to build that metallic screen. It is not the semiconductive insulation screen, the main phase conductor or the outer armour.
Illustrative single-core cable cross-section. The highlighted layer shows the intended material location. Wire count and layer thickness are illustrative, not a recommended cable specification; final construction and approval are project-specific.
Why Review the Screen Material?
Screen-wire mass
An aluminum-based core changes the material density. The useful comparison is the wire mass per cable kilometre after the required screen area, wire count and lay geometry have been determined—not the mass of two wires of equal diameter alone.
Processing consistency
Define the wire condition needed for paying off, screen laying, bending and termination. Diameter variation, surface defects and copper-layer integrity belong in the qualification plan alongside electrical measurements.
A documented evaluation
Use an agreed specification and sample-validation plan to decide whether an alternative is viable. Where the applicable rules or the engineering results do not support a change, retain the specified copper solution.
Material Routes for Evaluation
| Route | Core and exterior | Evaluation focus |
|---|---|---|
| Existing copper screen | Customer's approved copper-wire construction | Establish the reference design, electrical requirements and present cost per cable kilometre |
| CCA | Aluminum core with a continuous copper exterior | Copper fraction, electrical properties, geometry, wire mass and processing condition |
| Copper-clad aluminum alloy | Aluminum-alloy core with a continuous copper exterior | Alloy identity and the required balance of electrical and mechanical properties |
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Raytron uses HTCCA for a copper-clad aluminum-alloy product family. A trade name is not a substitute for a specified alloy, copper fraction, temper, test method or acceptance limit.
What to specify
| Item | How to define it |
|---|---|
| Wire diameter | Nominal diameter, tolerance and ovality; Ø1.70 mm and Ø2.00 mm may be used as example enquiry sizes, not universal design recommendations |
| Copper fraction | Explicitly state vol.% and its permitted range; use an approved conversion if a weight fraction is also required |
| Core | Aluminum or a named aluminum alloy, linked to the agreed material specification |
| Electrical property | Approved resistivity or conductivity requirement at 20°C; distinguish a requirement from a measured lot result |
| Mechanical condition | Temper, tensile strength and elongation together with the test method and gauge length |
| Copper exterior | Agreed minimum local thickness, coverage, surface quality and interface requirements |
| Delivery | Spool dimensions, wire length or net mass, payoff requirements and batch identification |
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These enquiry fields are not a declaration of standard stock or a blanket performance guarantee. Confirm available combinations during the technical review.
What to Define for a Raytron Screen-Wire Trial
| Item | What can be published |
|---|---|
| Scope of supply | A single bare round wire used to build the metallic screen, not a finished cable |
| Material route | CCA and copper-clad aluminum alloy are discussed separately; the core, copper fraction and temper follow the agreed specification |
| Specification | Diameter, tolerance, copper-layer requirement, electrical and mechanical properties, and the customer's downstream process |
| Packaging | Spool, net mass or wire length, payoff method and batch traceability |
| First-round output | Candidate specification, missing inputs, and the sample and validation scope; no prior promise of passing |
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Start with your existing copper-screen drawing. We will identify what can be compared now, which inputs are still missing, and what evidence is needed before a wire trial.
Sample scope and quantity are agreed during technical review. Production MOQ is confirmed against the material specification and supply conditions.
Application Development Case
Starting from a Copper-Wire Screen Baseline
Illustrative engineering review—not a customer installation or field-performance report
- Application
- Metallic wire screening of a medium-voltage cable
- Development question
- Can an alternative wire construction reduce copper use or screen-wire mass while meeting the approved cable and system requirements?
The review starts with the customer's existing cable drawing and copper-screen specification. That baseline records the number and diameter of the wires, lay geometry, screen resistance, required fault current and duration, available construction space, and the proposed bonding and termination arrangement.
CCA and alloy-core alternatives are then assessed as complete candidate screen constructions. The comparison must not assume that a lower-density material can replace copper at an unchanged wire count and diameter.
Compare on the Right Basis
| Comparison | What it can tell you | What it cannot establish |
|---|---|---|
| Equal outside wire diameter | Geometric and material-mass differences | Equal resistance or equal fault duty |
| Equal screen DC resistance at 20°C | A resistance-based starting point for area selection | Equal short-circuit withstand, contact durability or cable approval |
| Qualified complete screen construction | Performance against the agreed screen and cable requirements | Universal suitability for other cable designs or markets |
Expected engineering deliverable: a candidate material specification, screen-construction comparison, sample plan and list of qualification items. This page does not claim completed customer approval or measured savings.
A Simple Resistance Example
Illustrative calculation only — not a Raytron grade specification
Assume a reference copper screen with 16 mm² total metallic wire area and 100% IACS conductivity. For illustration, assume the candidate material has 65% IACS conductivity. If the effective wire lengths and lay factors are the same, an equal-DC-resistance estimate gives:
Candidate area = Copper reference area × Copper conductivity / Candidate conductivity
= 16 × 100 / 65Candidate area ≈24.6 mm²
- Copper reference area: 16 mm²
- Reference conductivity: 100% IACS
- Candidate conductivity (assumed): 65% IACS
- Lay factor: equal
- Data status: Illustrative calculation only — not a product specification
This example explains why an equal-resistance design can need more metallic area than an equal-diameter comparison suggests. The assumed 65% value is not a product guarantee. Final wire count, diameter and area must also account for tolerances and the actual cable construction.
Equal DC resistance is not proof of equal short-circuit withstand. Thermal evaluation requires additional material and construction inputs; the review must not simply reuse a copper short-circuit coefficient for a composite material.
From Enquiry to Qualification
-
1 — Confirm the permitted material route
Identify the target market, cable specification, utility or customer requirements and any material restrictions. Resolve an explicit copper requirement before developing a substitution proposal.
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2 — Establish the design baseline
Record the current screen construction and the required resistance, fault duty, bonding arrangement, connection method and dimensional limits.
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3 — Define and test the candidate wire
Agree the copper fraction, core material, diameter, mechanical condition, surface requirements and sample test plan. Verify results against the specification rather than against an unlabelled catalogue average.
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4 — Validate in the cable construction
Evaluate screen laying, bending, screen continuity, connection compatibility and the applicable electrical, thermal and environmental duties. The scope and responsible test provider are agreed with the cable manufacturer.
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5 — Release only against approved requirements
Use the approved material specification, qualification evidence and batch-control plan for subsequent supply. A successful wire test alone does not qualify every finished cable design.
What the Validation Plan Should Cover
| Review area | Required question |
|---|---|
| Electrical | Does the completed screen meet its resistance requirement at the specified reference temperature? |
| Fault duty | What current must this screen carry, for how long, and under which thermal limits? |
| Service operation | Are induced screen voltages, circulating-current losses and thermal effects acceptable for the actual frequency, cable geometry and bonding arrangement? |
| Geometry | Will the number, diameter, spacing and lay of the wires fit the cable construction? |
| Mechanical | Can the wire tolerate the intended laying, bending and termination operations? |
| Copper coverage | Are local minimum thickness, continuity and interface integrity consistent with the agreed specification? |
| Connections | Have the actual earthing and termination components been evaluated for this composite wire? |
| Environment | Are cut ends, moisture exposure and relevant material interfaces addressed in the cable and accessory design? |
| Traceability | Can the sample and production lots be linked to their material and inspection records? |
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Three distinctions matter here: total system fault current is not the current allocated to this screen; material resistivity (Ω·mm²/m) is not the finished screen resistance (Ω/km); and a 20 °C reference value is not the operating or fault temperature. The cable or system designer confirms the applicable method and parameters.
A copper exterior does not automatically establish compatibility with every copper-wire connector. Corrosion-control measures must preserve the electrical continuity required by the bonding design.
Who Provides the Inputs and Evidence?
| Work | Main inputs | Delivery evidence | Suggested responsibility |
|---|---|---|---|
| Design baseline | Current drawing, wire count and diameter, lay construction, target market | Baseline conditions and a list of missing inputs | Cable manufacturer provides; both parties confirm |
| Candidate wire | Core material, copper fraction, temper, electrical and mechanical requirements | A sample specification confirmed by both parties | Raytron and the customer confirm together |
| Material inspection | Samples, test methods and sampling plan | Agreed dimensional, copper-layer, electrical and mechanical records | Raytron provides within its actual capability and as commissioned |
| Cable and accessory validation | Trial cable, connectors, bonding arrangement, fault and environmental conditions | Agreed trial or test records | Cable maker, accessory supplier or an accredited body, per project division |
| Supply release | Approved specification, acceptance results, traceability requirements | Approved status and batch-control requirements | The customer's authorised party approves; the supplier releases accordingly |
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This is a suggested collaboration arrangement. The actual test scope, executing body and approval responsibility are agreed per project. Raytron does not claim to perform all finished-cable or high-current type tests itself, and no third-party qualification is created on a customer's behalf.
Evidence and Technical Documents
A useful qualification package can include the agreed wire specification, core-material identification, copper-fraction basis, cross-section measurements, electrical and mechanical results, sample identification and the approved downstream test plan.
Read technical documents against their stated status: design requirement, illustrative calculation, measured result or approved qualification result. The availability and scope of project-specific reports are confirmed during the review.
Related resources
How to read a document status
- Design requirement
- Illustrative calculation
- Measured lot result
- Approved qualification result
No measured or approved performance record is published on this page. Only the illustrative calculation above is shown.
Standards note
| Standard source | What the page may state | What cannot be inferred |
|---|---|---|
| ASTM B566-04a(2025) | Scope and classes of bare round CCA wire; the copper volume fraction and temper must be specified | That any alloy core, copper fraction or size automatically belongs to an approved class |
| IEC 60502-2:2014+AMD1:2024 CSV | Its published scope covers completed power cables at 6–30 kV, corresponding to Um 7.2–36 kV, and their construction, dimensions and tests | That any MV cable, application or CCA substitution is automatically compliant |
| IEC 60949:1988 with applicable contract amendments | A reference for thermally permissible short-circuit current calculation | That pure-copper parameters alone prove short-circuit equivalence for a composite material |
| Applicable parts of IEC 60287 | A reference for steady-state current rating and loss evaluation | A thermal performance guarantee without validating the model, material parameters and actual installation |
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These references are not interchangeable approvals and do not, by their names alone, establish suitability of a particular alloy-core wire or finished cable. Review against the applicable standard version in the project contract.
Application note · Content updated 2026-09-27
Frequently Asked Questions
Can CCA replace copper screen wire at the same diameter?
Not automatically. Material conductivity, wire count, lay geometry and the required screen resistance must be considered. Fault duty, termination compatibility and the permitted cable construction also need separate evaluation.
Is the metallic screen the same as the semiconductive insulation screen?
No. They are different parts of the cable construction. This page addresses the individual metallic wires, not the semiconductive material around the insulation.
What is the difference between CCA and copper-clad aluminum alloy?
The core material differs. An alloy-core product must be identified by its approved material specification, electrical properties and mechanical condition. Do not select it by the HTCCA trade name alone.
Does equal DC resistance prove equal short-circuit performance?
No. Short-circuit performance also depends on thermal properties, permitted temperatures, fault duration, construction and connections. Equal resistance is only one input to the assessment.
Is 10% copper the same as 10% copper by weight?
No. This page specifies copper fraction by volume unless explicitly stated otherwise. Weight fraction uses the densities of copper and the selected core material and must be labelled separately.
Does a copper exterior make every copper-wire termination suitable?
No. The connector, contact arrangement, mechanical loading and environmental conditions must be evaluated for the actual composite wire and cable system.
Does this page certify an IEC-compliant finished cable?
No. It describes a screen-wire application and qualification approach. Finished-cable compliance requires the relevant construction, tests and approvals; a bare-wire material result is not a finished-cable certificate.
What should I send for an initial review?
Describe the target market and cable specification, your current screen construction, and any known resistance and fault-duty requirements. A partial specification is enough to start identifying the missing design inputs.
Review Your MV Screen-Wire Requirement with Raytron
Share your current screen construction and target requirements. We will clarify the candidate wire specification, missing design inputs and sample-evaluation scope.
Start with what you know. Send a brief description of your screen-wire requirement; the technical details below are optional.
Submitting information starts an engineering review; it does not approve a material substitution.
Technical references and scope
- Eland Cables — purpose of a metallic screen in MV cables External reference
- IEC 60949 — thermally permissible short-circuit current calculation (scope) External reference
- ASTM B566-04a(2025) — bare round copper-clad aluminum wire (scope and classes) External reference
- IEC 60502-2 — power cables with extruded insulation (scope) External reference
These are scope references for public standards and resources. They do not constitute certification of a material or a finished cable.