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
CCA Wire for MV Metallic Screens
Compare copper use, screen-wire mass and cost per kilometre for your existing cable construction.
Send your copper-screen drawing. We will help define a candidate wire specification and the material and cable tests needed for your project.
Aluminum-core and aluminum-alloy-core options are specified separately.
- At a glance
- Candidate wire specification · Cost comparison per cable kilometre · Sample and validation plan
For metallic wire screens, not phase conductors or semiconductive screens. Equal resistance alone does not establish equal fault duty.
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.
Single-core cable cross-section with the metallic wire screen highlighted outside the insulation screen.
Wire specification
Aluminum-core CCA and aluminum-alloy-core wire are specified separately. Match the individual wire, its condition and guaranteed properties to the proposed cable construction.
A candidate wire specification defines diameter, core material, temper, copper content and its measurement basis, together with electrical and mechanical requirements.
Request a candidate wire specificationCompare screen-wire cost and mass per cable kilometre
Compare Your Copper and Candidate Wire Schemes
Use actual metallic area, or count × individual wire diameter. Prices are optional. Results compare wire material per cable kilometre; they do not include the complete cable.
The example uses nominal area as actual area. Conductivity, density and copper fraction are entered separately; update them with your material data.
Model illustration
Equal-resistance resizing changes geometry. Check wire count, space, outside diameter and fault validation separately.
Candidate conductivity needed for your target
Estimated candidate R20:
The entered target exceeds the 100%IACS reference. Verify the geometry and material basis.
Estimated R20
ohm/cable km
Wire retained in cable
kg/cable km
Copper in the wire
kg/cable km
Cost not calculated: no prices entered.
Matching resistance at the reference temperature is an electrical sizing comparison. Fault thermal stability also depends on fault current and duration, permitted initial and final temperatures, the complete screen construction and its joints; it is a separate cable-design check.
Full electrical, mass and material-cost results
Scroll the results table horizontally on small screens.
| Quantity and unit | Copper baseline | Candidate scheme |
|---|---|---|
| Metallic areamm² | — | — |
| Estimated R20Ω/cable km | — | — |
| R20 margin to entered target% (model only) | — | — |
| Conductivity needed for target%IACS | — | — |
| Density usedg/cm³ | — | — |
| Wire retained in cablekg/cable km | — | — |
| Copper estimatekg/cable km | — | — |
| Copper weight fractionwt.% | — | — |
| Core estimate (component model only)kg/cable km | — | — |
| Wire to purchase at entered utilizationkg/cable km | — | — |
| Recurring wire material costentered currency/cable km | — | — |
Optional project scale and incremental validation cost
Wire-cost difference: baseline minus candidate
- Difference per cable km
- —
- Difference as % of baseline
- —
- Annual gross difference
- —
- Project net difference after entered one-time cost
- —
- Break-even cable km (positive difference only)
- —
Wire-material cost difference calculated from the entered prices, utilization and project scale.
Check the indicated inputs.
Send these inputs to develop a wire specification for your project.
Your prices stay in this browser session until you choose to submit an inquiry.
Review the transferable calculation summary
Model, Units and Assumptions
All included parallel wires share one material and path factor. Individual metallic cross-sections exclude gaps; k is wire length / axial cable length. Complex layers or different wire paths need separate construction analysis.
100%IACS reference resistivity is 0.017241 Ω·mm²/m at 20°C. A = n × π × d² / 4; R20 = 1724.1 × k / (c × A); required c = 1724.1 × k / (A × Rmax). c is entered as a percentage number, such as 65, not 0.65.
Wire mass per cable km = A × k × density. Ideal component density = f × copper density + (1 − f) × core density. Copper weight fraction = f × copper density / ideal density. A measured total density is a separate mode; it does not establish an exact component mass split.
To convert a known copper weight fraction w to volume fraction: f = (w / copper density) / [(w / copper density) + ((1 − w) / core density)]. Use matching measured inputs or clearly labelled ideal parameters, not an inferred alloy grade.
Purchase mass = retained mass / utilization. Recurring wire cost = purchase mass × price per kg + only additional costs absent from that price. No automatic scrap credit, ampacity, fault capacity, temperature, lifetime, regulatory acceptance or promised saving is calculated.
Copper equalizing tape, terminations and contact contributions are excluded from the resistance model. Finished-cable measurement and project approval remain separate.
Wire inspection
Wire inspection covers dimensions, copper-layer continuity, electrical resistance and mechanical properties against the selected specification.
Discuss inspection requirementsWire inspection and finished-cable qualification address different requirements: material properties, cable processing, connections and service duty.
From drawing review to cable validation
1. Drawing and cost review
- Your team
- Current copper-wire arrangement or drawing, target market, known resistance and quantity.
- Raytron technical support
- Candidate wire specification, resistance and mass comparison, and a sample trial proposal.
- Next stage
- Agree the application, candidate material and sample task before ordering a trial.
2. Wire and machine trial
- Your team
- Agree trial quantity, spool, process checks and the cable-machine trial owner.
- Raytron technical support
- Agree inspection items, sample charges, responsibilities and the adjustment route if a trial does not meet the agreed requirements.
- Next stage
- Meet the agreed wire and processing criteria. Wire results alone do not release a finished cable.
3. Cable and accessory validation
- Your team
- Cable maker and project parties confirm fault, connection and environmental test scope, institution, costs and release owner.
- Raytron technical support
- Provide the agreed material inputs for the project validation plan.
- Next stage
- The responsible project parties approve the finished-cable and accessory evidence; timing is agreed per project.
Samples and supply conditions
The quotation sets sample quantity, charges, packaging, delivery and joint requirements for the selected wire specification.
Discuss sample quantity and supply conditionsAgree laboratory samples, machine trials and production orders separately. Validation responsibilities, costs and timing are confirmed with the project parties.
Detailed engineering inputs, the 16 mm² copper / 65% IACS model example, test methods and responsibilities
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.
Screen-Wire Options
| 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 |
Scroll this table horizontally to see all columns.
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 |
Scroll this table horizontally to see all columns.
Send the wire construction and dimensions to define the proposed supply specification.
What to Define for a Raytron Screen-Wire Trial
| Item | What to agree |
|---|---|
| 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 |
| What the review returns | A candidate wire specification, screen-construction comparison and sample-test plan. |
Scroll this table horizontally to see all columns.
Start with your existing copper-screen drawing. Our technical team can compare resistance, material mass and construction options, then develop a sample-test plan.
Sample size, packaging and test requirements follow the selected wire construction. The quotation defines quantity and delivery for the order.
Example: Reviewing a Copper-Wire Screen
Starting from a Copper-Wire Screen Baseline
Illustrative design review
- Application
- Metallic wire screening of a medium-voltage cable
- Design 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 |
The review returns a candidate material specification, screen-construction comparison, sample plan and qualification items.
A Simple Resistance Example
Design calculation — example inputs
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: Design calculation — example inputs
This example explains why an equal-resistance design can need more metallic area than an equal-diameter comparison suggests. The calculation uses 65% IACS as the candidate input. 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.
Engineering responsibilities
| Work | Main inputs | Delivery evidence | Suggested responsibility |
|---|---|---|---|
| Design baseline | Current drawing, wire count and diameter, lay construction, target market | Cable drawing and design requirements | 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, for the material inspection specified in the order |
| 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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The cable manufacturer, material supplier and selected test provider define the test scope and responsibilities for the cable design. Finished-cable and accessory qualification follows the project specification.
Wire inspection 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.
The wire specification defines the required properties and inspection methods. Lot records identify the sample, test conditions and measured results; cable qualification addresses the complete construction.
Related resources
Technical document types
- Design requirement
- Illustrative calculation
- Measured lot result
- Approved qualification result
The resistance example above uses stated calculation assumptions. Material inspection and cable qualification use the selected construction and test conditions.
Standards note
| Standard source | Relevant scope | Product and design scope |
|---|---|---|
| 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 2026-10-20
Share the drawing-review checklist with your team
These two-page checklists cover inquiry inputs, model assumptions, inspection methods, trial steps and project responsibilities.
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.
Looking for Low-Voltage Concentric Neutral Wire?
Concentric neutrals in service cables have a different duty and specification. See the dedicated low-voltage application for its utility references and resistance inputs.
Explore LV concentric neutral wireReview 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 a screen-wire review
Choose a quotation, a sample request or a specification recommendation. Add the drawing and details you have in the shared inquiry form.
The inquiry form accepts one drawing or specification up to 20 MB. File content and type are checked before notification. Keep source requirements separate from your calculated scheme and project inputs.
Email and WhatsApp open a draft; you decide what to attach and send.
Raytron — Engineering Every Micron.
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.