Low Grade vs High Grade Cable: The Copper Recovery Percentage Explained | Dunmow Group

Here is the single most important fact every UK insulated cable seller needs to understand: the weighbridge does not pay you for the cable; it pays you for the copper inside it. The total weight of cable you deliver is the gross commercial quantity, but the settlement reflects the proportion of that weight that is actually recoverable copper after the cable has been processed through a granulator and separator chain. That proportion, the copper recovery percentage, varies from around 15% for the lowest-grade signal cable to 70% or more for the heaviest power cable and EV charge leads. The gap is the entire commercial story of insulated cable recycling.

I have worked in liquid waste and metals recycling across Essex and the South East for many years, joining the Dunmow Group team when Dunmow acquired EWD. My day-to-day work spans hazardous liquid waste, specialty metals and the broader non-ferrous recycling chain, including the cable processing operations at the engineering end of the metals weighbridge. This article explains how cable recovery percentages work, why low-grade and high-grade cable settle so differently, what happens to your cable load after it leaves the weighbridge, and how electricians, M&E contractors, demolition firms, telecoms decommissioning specialists and other trade customers can present cable loads that achieve the right settlement.

The article is for the trade community handling continuous insulated cable volumes. The commercial decision on whether to strip cable or sell it whole is covered in Martin Whillock’s Cable Stripping vs Selling Whole pillar article. The domestic cable typology is covered in Mark Chinsky’s What “Household Cable” Means at the Scrap Yard article. This piece addresses different ground: the engineering and processing realities that determine the recovery percentage in the first place.

What “Copper Recovery Percentage” Actually Means

When insulated cable arrives at a UK recycling facility, the weighbridge records the total gross weight of the load. The cable is then processed through a mechanical chain (described in detail below) that separates the copper from the insulation, yielding clean copper granules. The ratio of recovered copper weight to the original total cable weight is the recovery percentage, also known as the copper yield or metal content.

For example: a tonne of clean twin-and-earth (T&E) installation cable typically contains 550 to 650 kilograms of copper, so the recovery percentage is 55-65%. A tonne of telephone or alarm cable typically contains 150 to 300 kilograms of copper, with a recovery percentage of 15-30%. Both loads are sold to the yard at a per-kilogram cable rate, and the rate reflects the recovery percentage the cable type is known to yield during processing. Higher-recovery cable commands a substantially higher per-kilogram rate than lower-recovery cable.

For the trade seller, this matters because it explains why cable types that look superficially similar (PVC-sheathed flex of various thicknesses) settle at materially different rates. The differential is neither arbitrary nor yard-specific; it is an engineering reality determined by what each cable type contains.

The Cable Engineering: Why Some Cables Carry More Copper

Cable types are designed for specific electrical applications, and the engineering decisions made at the design stage determine the copper-to-insulation ratio. Three factors dominate:

Conductor cross-section. The defining variable. Power cables carrying large currents require a substantial conductor cross-section (measured in square millimetres) to keep voltage drop and resistive heating within safe limits. UK domestic mains installation cable is available in 1.0 mm², 1.5 mm², 2.5 mm², 4.0 mm², and 6.0 mm² for lighting, ring main, cooker, and shower circuits, respectively. Heavy power cables used in distribution and commercial installations are available in 16 mm², 25 mm², 50 mm², 95 mm², 150 mm², and larger sizes. A larger conductor cross-section means more copper per metre of cable and a higher copper-to-insulation ratio overall.

By contrast, signal, telephone, alarm, data and decorative flex cables carry only small currents (milliamps for signal cable, low watts for alarm and lamp flex) and use small cross-section conductors of 0.22 mm² to 0.75 mm². The cables are designed to be light, flexible and inexpensive, with minimal copper and generous insulation.

Insulation thickness and material. UK domestic and commercial cable insulation is predominantly PVC, with cross-linked polyethylene (XLPE) used for higher-voltage and higher-temperature cables. Insulation thickness depends on the rated voltage: low-voltage cable uses thin insulation, while medium- and high-voltage cable uses substantially thicker insulation. Heavy power cable also typically uses additional armour layers (steel wire armour, aluminium tape, lead sheath) that add to the gross weight without contributing copper. The thicker the insulation and armour relative to the conductor, the lower the copper recovery percentage.

Conductor material itself. Most UK cable uses electrolytic-grade copper conductors (annealed copper, sometimes denoted as Cu-ETP), with copper purity above 99.9%. Several variants encountered in scrap loads materially affect the grading:

• Tinned copper uses an electrolytic copper conductor with a thin tin coating, common in marine, automotive and certain electrical applications where corrosion resistance matters. Tinned copper grades as clean copper recovery but at a slight discount because the tin coating dilutes the final melt purity.
• Silver-plated copper is used in high-frequency and aerospace cables. The silver content can elevate the settlement above standard copper grading, but only when the cable is identified at delivery and graded accordingly.
• Copper-clad aluminium (CCA) uses an aluminium conductor with a thin copper cladding. CCA cable is lightweight, inexpensive and increasingly common in low-cost imported audio, HDMI and some installation cable. CCA recovery yields aluminium plus a small amount of copper from the cladding, settling at a fraction of the rate of a solid-copper cable of the same dimensions. CCA misrepresented as solid copper is the most common cable-related fraud at UK weighbridges.
• EV charge leads (mode-2 and mode-3 charging cables): 2.5 mm² to 6.0 mm² conductors, three- or five-core construction. Heavy PVC-sheathed flex. Recovery typically 55-70%. The highest copper-to-insulation ratio of any common household cable.
• Heavy power and distribution cable: 16 mm² to 240 mm² conductors. Three-core or single-core construction with XLPE or PVC insulation, often steel-wire armoured. Recovery typically 50-65% (the SWA armour reduces the percentage; cable without armour runs higher).
• Twin-and-Earth (T&E) installation cable (2.5 mm² and above): UK domestic and commercial mains installation cable. Recovery typically 55-65%.
• Traction cable: heavy power cable for rail, mining, forklift and industrial traction applications. Heavy cross-section conductors with PVC or rubber insulation. Recovery typically 55-70%.
• Welding cable: very flexible, heavy-cross-section copper cable, finely stranded for flexibility. Recovery typically 60-70%.
• Twin-and-Earth (T&E) at 1.5 mm² and below: lighting circuits and small power. Recovery typically 45-55%.
• Extension leads and IEC kettle leads: moulded-plug 0.75-1.5 mm² flex. Recovery typically 40-55% (plugs and connectors reduce the percentage).
• White-goods appliance flex: captive flex on washing machines, dishwashers, and ovens. Recovery typically 45-55%.
• Lawnmower and outdoor equipment flex: heavy-duty PVC flex, 1.0-1.5 mm². Recovery typically 45-55%.
• Lamp flex and decorative cable: 0.5-0.75 mm². Recovery typically 35-45%.
• Burglar alarm cable: multi-core, fine-conductor signal cable. Recovery typically 15-30%.
• Telephone and broadband cable: indoor extension, Cat5/Cat5e/Cat6 data cable. Recovery typically 20-35%.
• TV aerial and satellite cable (RG6 coaxial): single central conductor with copper or CCA braid. Recovery typically 25-40%.
• Computer, USB, HDMI and audio interconnect cable: mixed-construction, fine-conductor cable. Recovery typically 20-35%.
• Doorbell, thermostat and signal cable (bell wire): thin two-core. Recovery typically 15-30%.
• Christmas light flex and decorative cable: very thin two-core with attached lights. Recovery typically 15-25%.
• Druid: the standard ISRI specification for low-grade insulated copper wire and cable, with a typical recovery percentage of 30% or less. The default category for fine-conductor signal, alarm and decorative cable.
• Berry-equivalent insulated: mid-grade insulated cable with a typical recovery percentage of 40-55%. Covers domestic and light commercial installation cable, extension leads and white-goods flex.
• Heavy insulated power cable: high-grade insulated cable with a typical recovery percentage of 55-70%. Covers EV charging leads, traction cable, heavy distribution cable and large-cross-section T&E.
• Bright bare copper wire (Barley): uninsulated copper wire, the premium copper grade with 100% recovery. Achieved by mechanical or manual stripping.
• Steel wire armour (SWA) and mineral-insulated cable (MICC): the armour and mineral filling add weight without adding copper. The settlement reflects this through grade reduction unless segregated.
• Plug heads, IEC connectors, junction boxes and inline switches: mixed-material components that add gross weight without adding copper content.
• CCA (copper-clad aluminium) cable misrepresented as solid copper: identified during inspection through cross-sectional examination and a weight-per-length check; settled at the correct CCA rate, not the copper rate.
• Wet, muddy, oily, or paint-contaminated cable: reduces processing yield and may require pre-processing or cleaning before granulation.
• Tangled, full-length cable runs: cutting the cable into manageable lengths (typically under 1.5 m) improves processing efficiency. Long, tangled runs slow the granulator infeed and may incur a small grading penalty.
• Mixed grades dumped in one container: the load defaults to the lower-grade rate unless segregated at source.
• Licensing: every scrap metal dealer must hold a council-issued site licence or a collector’s licence. Dunmow Group holds full site licences for each of our three Essex facilities. [2][3]
• Cashless payment (Section 12): It is a criminal offence to pay for scrap metal in cash, with no exemptions. Permitted methods are non-transferable (“crossed”) cheques or electronic transfers. For trade accounts, settlement is by monthly electronic transfer, with a full breakdown of transactions. [4]
• ID verification: dealers must verify identity (UK photocard driving licence or passport, supported by proof of address dated within the previous three months, where required) before each transaction. For trade accounts, verification is completed at account opening. [4]
• Record-keeping: every transaction is logged (seller, ID, vehicle registration, material, weight, price, payment method), and records are retained for at least three years for inspection by police or council enforcement officers. [2][4]

For the trade seller, the engineering implication is straightforward: knowing the cable type (ideally the BS 6004 or equivalent specification it was supplied to) tells you in advance what recovery percentage to expect at settlement. The yard’s job is to verify that prediction during inspection and processing.

The Mechanical Processing Chain: How Recovery Actually Happens

This is the section that requires a processing-engineering perspective. After the cable is weighed and graded, the load goes through a multi-stage mechanical processing chain that physically separates the copper from the insulation. Modern UK cable recycling plants typically include the following stages:

1. Primary granulator (or shredder). The first stage processes the incoming cable, cutting it into small granules, typically 5 mm to 10 mm in size. The granulator uses a high-speed rotating rotor with multiple cutting blades that engage fixed counter-blades, producing a stream of mixed copper-and-insulation granules. The cutting action liberates the copper from the insulation; without granulation, the copper and insulation remain mechanically bonded.

2. Secondary granulator (refining mill). A finer cutting stage that further reduces granule size, typically to 2-4 mm. This stage maximises liberation, ensuring that even the smallest copper conductors are physically separated from the surrounding insulation. Cables with fine-conductor construction (alarm, telephone, signal cable) require more aggressive secondary granulation because the conductor diameter approaches the limit of mechanical separation.

3. Air separation (zigzag separator). The granulated mixed stream is passed through a vertical air column. Low-density insulation particles (PVC, XLPE, polyethylene) are carried upwards by the airflow, while high-density copper granules fall through and are collected at the base. This is the primary mass-separation stage, typically removing 90-95% of the insulation in a single pass.

4. Vibratory air table (density separation). The remaining mixed fraction is passed over a vibrating, slightly inclined air-fluidised table. Density differences between residual copper and trapped insulation cause the materials to separate across the table surface, with copper concentrating at the heavy outlet and insulation at the light outlet. This stage recovers copper that the primary air separation missed.

5. Eddy current separator (ECS). A high-speed rotating magnetic drum generates an alternating magnetic field, inducing eddy currents in non-ferrous metals. These currents produce a repulsive force that ejects copper (and aluminium, where present) from the conveyor stream, thereby separating residual non-ferrous metal from the remaining insulation fraction. ECS is particularly important for recovering very small copper granules and CCA aluminium that the vibratory table missed.

6. Optical sorting (premium plants). The highest-specification plants include an optical or colour sorter that identifies copper granules by their distinctive reddish colour and ejects them from the final insulation stream via high-speed compressed-air jets. Optical sorting captures fines and trace copper that mechanical density separation cannot fully recover. Modern cable recycling plants with full optical sorting achieve copper recovery rates of 99%+ from the input feedstock.

The chain produces two streams: clean copper granules (the recovered metal, sold into the secondary copper market) and clean insulation granules (the recovered plastic, sold for plastic recycling or, depending on quality, routed to energy-from-waste).

The critical point for the trade seller is this: the chain has limits. Even modern optical-sort plants do not recover 100% of the copper from heavily contaminated or fine-conductor cable. The recovery percentage quoted at the weighbridge reflects realistic plant yields for each cable type, not theoretical maximums. Fine-conductor cable (alarm, telephone, very thin flex) yields less because the small conductor diameter approaches the limit of mechanical liberation; some copper exits the plant trapped within fully encapsulated insulation fragments and is not recovered.

Low Grade vs High Grade Cable: The Structured Comparison

The recovery percentage classification broadly divides UK insulated cable into low-grade and high-grade categories. The structured comparison:

HIGH-GRADE CABLE (Recovery percentage 50-70%, premium ISRI grading)

MEDIUM-GRADE CABLE (Recovery percentage 35-55%, mid-range ISRI grading)

LOW-GRADE CABLE (Recovery percentage 15-35%, ISRI Druid specification)

For the trade seller handling continuous cable volumes, the operational implication is clear. Segregating high-grade from low-grade at source captures the price differential between the categories, which is material at any meaningful tonnage. The yard cannot pay a high-grade rate on a mixed load because the average recovery percentage is dragged down by the low-grade content. Twenty minutes of segregation in the van or skip pays back at settlement.

ISRI Grading Alignment

UK scrap yards align their insulated cable grading with the international ISRI/ReMA non-ferrous specifications. The principal cable grades for trade settlement:

Source segregation by cable type before delivery brings each portion of the load into its proper ISRI alignment, with the settlement reflecting the actual recovery rate the cable will yield.

What Contaminates a Cable Load and Reduces the Recovery Percentage

Even within a clean cable load, contamination reduces the effective recovery rate:

The single most consistent piece of advice from my processing-engineering perspective: clean cable, cut to length, segregated by recovery category, presented dry, with non-cable components removed, captures the recovery percentage the cable type can actually yield. Everything else causes either grading reduction or processing inefficiency.

The Law: Scrap Metal Dealers Act 2013

Every legitimate transaction involving insulated cable in England and Wales is governed by the Scrap Metal Dealers Act 2013 (SMDA 2013), which came into force on 1 October 2013 in direct response to the UK cable theft crisis. The Act is particularly relevant to cable because copper-stripped infrastructure theft (railway signalling cable, street lighting cable, telecoms cable, copper grounding) was a primary driver of the legislation. [1][2]

Four core requirements apply to every legitimate cable transaction:

For weighbridge operators at Dunmow Group, the SMDA verification process is the safeguard for both legitimate sellers and the wider community. Cable theft from railway infrastructure, street lighting, telecoms and substations carries severe enforcement consequences; legitimate trade and demolition contractors with documented provenance pass through the weighbridge without difficulty.

How a Cable Weighbridge Transaction Should Work

At a properly run facility, the process is the same every time. If a buyer skips a step, it is a signal that something is wrong.

1. Weighed in (gross). The loaded vehicle is weighed on a calibrated weighbridge.
2. Identity verified. The seller presents photographic ID. For trade accounts, credentials are verified.
3. Cables are inspected and graded. A trained operator inspects the load, identifies the dominant cable types, checks for CCA indicators, verifies that non-cable components are within acceptable limits, and assigns the appropriate grade categories (high-grade, medium-grade, low-grade Druid, or mixed). Segregated loads are recorded separately.
4. Material discharged. Each grade is tipped into its designated bay for downstream processing.
5. Weighed out (tare). The empty vehicle is reweighed; net weight is gross weight minus tare.
6. Ticket issued and payment processed. The weighbridge ticket records all transaction details, including the grade-by-grade breakdown. Payment is processed by electronic transfer, normally on the same day, at our Chelmsford metals facility.

For trade accounts, the entire transaction takes minutes, and the settlement appears on the monthly statement.

The Trade Account Advantage for Cable Sellers

For electricians, M&E contractors, demolition firms, telecoms decommissioning specialists, infrastructure contractors and cable jointers who generate insulated cable continuously, a trade account is the operational solution. A Dunmow Group trade account offers:

• Pre-verified ID and account details: no repeated verification on each visit.
• Monthly statement settlement for all non-ferrous and cable deliveries, eliminating per-visit administration costs.
• Priority weighbridge access at our Chelmsford metals facility.
• Roll-on, roll-off (RoRo) containers are delivered to depot, site or yard for trade operators with continuous output, available in 20, 30 and 40 cubic yard capacities. For sites generating heavy power cable, telecoms decommissioning waste or large infrastructure cable, dedicated cable containers prevent load mixing with general scrap.
• Multiple containers for grade segregation on sites generating both high-grade and low-grade cable, allowing each grade to be loaded into a separate container and settled at a distinct rate.
• Scheduled business collections for premises with continuous cable output (electrical contractor depots, M&E workshops, and telecoms maintenance hubs).
• Mixed-load handling for trade operators generating cable, copper, brass, aluminium and ferrous from the same job. One drop, one ticket, grade-by-grade settlement.
• Waste Transfer Notes and ISO-certified documentation are standard, covered by our ISO 9001/14001/45001 accreditations. [5]
• Chelmsford Metals: Regiment Business Park, Eagle Way, Chelmsford CM3 3FY. Mon to Fri 7:30 am to 4:30 pm.
• Colchester (Brightlingsea): Morses Lane, Brightlingsea CO7 0SD. Mon to Fri 7:30 am to 5:30 pm, Sat 7:00 am to 12:30 pm.
• Clacton: Gorse Lane Industrial Estate, Stephenson Road, Clacton-on-Sea CO15 4XA. Mon to Fri 7:30 am to 5:30 pm, Sat 7:30 am to 12:30 pm.
• Passion: We care that each cable seller leaves the weighbridge with the correct grade, weight and price. Cable grading is a technical discipline that rewards processing-engineering experience; my team and our weighbridge operators bring that expertise to every transaction.
• Innovation: Calibrated digital weighbridges, grade-by-grade live ticketing, CCA verification during inspection, electronic same-day settlement and a digital customer portal reduce paperwork and increase transparency. When the cable load contains a mix of types, our weighbridge team identifies the dominant grades and clearly explains the grading decision. The downstream processing chain (granulator, separator, eddy current, optical sorter) recovers copper at rates that justify the trade seller bringing the cable to us whole.
• Trust: Fully licensed under the Scrap Metal Dealers Act 2013, ISO 9001/14001/45001 certified, Environment Agency-permitted as a metals recycling facility, and aligned with the international ISRI/ReMA non-ferrous cable specifications. Every payment is electronic, every transaction is logged, and every grade is defensible.
• Community: Essex is our home. The electricians, M&E contractors, demolition firms, telecoms decommissioning specialists and infrastructure contractors across our county are the backbone of our cable weighbridge, alongside the larger commercial accounts. Cable theft is a community problem; the licensed weighbridge is the protection.
• Hard Work: A tight, professional operation that delivers value for money without compromising accuracy, safety or compliance. Cable processing is a technical exercise that rewards experience and proper plant; that is what our weighbridge team and our downstream processing partners do for each tonne of cable.

This is what running a tight ship looks like on the customer side: fast, easy, reliable, and fully compliant for every transaction.

Dunmow Group: Where Your Cable Becomes Same-Day Cash

We operate three scrap metal weighbridge facilities across Essex (Chelmsford, Colchester/Brightlingsea, and Clacton), accepting all categories of ferrous and non-ferrous metal, including the full range of insulated cable. Our dedicated metals weighbridge at Chelmsford handles the highest volume of cable, with grade-by-grade inspection, CCA verification of suspicious loads, and same-day electronic payment to the seller’s nominated account. [6]

That same-day payment is the operational standard we hold ourselves to. Do what we say. It is the first of our three customer commitments, and on the cable weighbridge it means a clear grade-by-grade ticket, an accurate weight, a verified grade, a fair price, and payment processed before the seller leaves the site.

For commercial trade customers with active sites generating significant cable volume, we deliver RoRo containers (20, 30 or 40 cubic yards) directly to site, schedule pickups around your programme, and settle your trade account on monthly terms. For mixed high-grade and low-grade strip-outs, we can deliver multiple containers in coordinated drops so each grade lands in its own container and settles at the correct rate.

Our Commitment: PITCH in Practice on the Cable Weighbridge

Our five core values, Passion, Innovation, Trust, Community, Hard Work (PITCH), are how we run the metals and processing operation, not a poster on the wall.

Choosing Dunmow Group means choosing a partner that is safe and compliant, delivers great value, and makes the entire cable recycling process fast and easy for trade customers. We hold ourselves to three operational drivers for every weighbridge ticket.

The Bottom Line

Insulated cable grading at the UK weighbridge is fundamentally about copper recovery percentage, not gross cable weight. The recovery percentage is an engineering outcome of three factors: the conductor cross-section (larger is more copper-rich), the insulation thickness and material (more insulation dilutes the percentage), and the conductor material itself (tinned copper, silver-plated copper, and copper-clad aluminium all grade differently from standard electrolytic copper). The processing chain (granulator, separator, eddy current, vibratory table, optical sorter) recovers copper from the insulation, with yields ranging from 99%+ on clean feedstock to materially lower on heavily contaminated or fine-conductor loads.

The structured low-grade vs high-grade comparison is the practical answer for trade sellers. High-grade cable (EV charge leads, heavy power, T&E, traction, welding cable) recovers at 50-70% and settles at premium insulated rates. Medium-grade cable (extension leads, white-goods flex, lawnmower flex, light installation cable) recovers at 35-55%. Low-grade cable (alarm, telephone, signal, decorative, Christmas lights) recovers at 15-30% and settles under the ISRI Druid specification. Segregation at source by recovery category is the operational lever that captures the differential.

What matters in every cable transaction is weighing at a licensed, calibrated, professionally run facility, with valid ID, traceable payment, grade-by-grade inspection, and a ticket that breaks the load down by recovery category. That is what we do at Dunmow Group, and it is why commercial trade customers handling cable across Essex consistently recover more value through our weighbridge than they would with a mixed-grade settlement elsewhere.

Bring your cable to Dunmow Group at Chelmsford, Colchester or Clacton and weigh in with confidence. For commercial strip-outs, infrastructure decommissioning and ongoing trade volumes, open a trade account and we will deliver the containers to you.

Chelmsford: 01245 466646 | Clacton: 01255 360031 | Colchester: 01206 307070 | dunmowgroup.com | WhatsApp: 07902 802802

References & Citations

[1] BBC News: Cable theft delays on railways fall sharply (80% reduction following SMDA 2013, illustrating the broader effectiveness of the Act in cable theft prevention specifically). https://www.bbc.co.uk/news/uk-29109733

[2] Scrap Metal Dealers Act 2013 | legislation.gov.uk. https://www.legislation.gov.uk/ukpga/2013/10/contents

[3] Dunmow Group: Certifications & Permits. https://www.dunmowgroup.com/about-us/documents/

[4] Home Office Supplementary Guidance: Cashless payment (Section 12) and identity verification under SMDA 2013. https://www.gov.uk/government/publications/scrap-metal-dealers-act-2013-supplementary-guidance/scrap-metal-dealers-act-2013-supplementary-guidance-accessible

[5] Dunmow Group: ISO 9001, ISO 14001, ISO 45001 accreditations. https://www.dunmowgroup.com/about-us/documents/

[6] Dunmow Group: Scrap Metal Recycling Essex. https://www.dunmowgroup.com/scrap-metal-essex/

[7] Recycled Materials Association (ReMA, formerly ISRI): ISRI Scrap Specifications, non-ferrous cable codes including Druid (insulated cable) and Barley (bare bright copper wire). https://www.isrispecs.org

[8] British Standards: BS 6004 Electric cables. PVC insulated and PVC sheathed cables for voltages up to and including 300/500 V, for electric power and lighting. The standard underpinning UK domestic and commercial mains installation cable.

[9] British Standards: BS 7671 Requirements for Electrical Installations. IET Wiring Regulations 18th Edition. The standard underpinning UK electrical installation practice and cable specification.

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