Copper Long Barrel Tubular Lugs

Copper Long Barrel Tubular Lugs

Electrical Accessories India manufactures Copper Long Barrel Tubular Lugs specifically engineered for medium-voltage (MV) and high-voltage (HV) cable terminations in power transmission networks, utility substations, power transformers, gas-insulated switchgear (GIS), and submarine cable systems. The defining characteristic of a long barrel lug is an extended barrel length — typically 1.5× to 2.5× the length of a standard tubular lug for the same conductor size — which dramatically increases the conductor-to-lug contact area, reduces contact resistance, improves mechanical pull-out strength, and critically provides the required conductor engagement length for heat-shrink, cold-shrink, and push-on insulation systems used in MV/HV cable joints and terminations. Manufactured from Electrolytic Tough Pitch (ETP) copper rod (C11000 / IS 1897) with conductivity ≥98% IACS, these lugs are available from 16 mm² to 630 mm² conductor size and are priced at US$16.80/kilogram ex-Jamnagar, India.

Product Overview

Why Long Barrel? Engineering Rationale for Extended Barrel Design

Standard tubular lugs (DIN 46235 short barrel) have barrel lengths designed for LV (up to 1 kV) applications where the primary requirement is crimped mechanical connection. For MV/HV cable accessories (6 kV to 220 kV), the insulation system — whether heat-shrink (XLPE sleeve), cold-shrink (pre-stretched silicone), or slip-on/push-on type — must overlap the barrel by a defined dimension to achieve the creepage and clearance distances required by IEC 60502-4, IEC 61238-1 Part 2, and cable accessory manufacturer installation instructions. Standard barrel lugs have insufficient length for this overlap. Long barrel lugs provide the necessary extended barrel (typically 50–150 mm of bare copper barrel beyond the compression zone) so that the insulation system can terminate cleanly on the barrel and the conductor screen can be controlled at the correct position per the electric stress management design of the accessory.

Barrel Dimensions & Ratio

For a 240 mm² conductor, a standard DIN 46235 lug barrel length is approximately 76 mm, while a long barrel version extends to 120–150 mm. For 630 mm², long barrel versions may reach 180–220 mm. The exact barrel length is specified by cable accessory manufacturers (Nexans Euromold, Raychem / TE Connectivity, 3M, Prysmian, etc.) for each accessory series, and EAI manufactures against these OEM dimensional drawings. The barrel inner bore is drilled to H7 tolerance (±0.05 mm for ≤35 mm², ±0.10 mm for larger sizes) to ensure consistent crimp quality. The palm (tongue) maintains standard DIN 46235 or BS 4579 dimensions for compatibility with transformer terminal pads and switchgear bushings.

Material: ETP Copper Rod — Grade and Traceability

Long barrel lugs are machined from ETP copper rod (8–50 mm diameter, IS 1897 / ASTM B187 C11000 / EN 13601 Cu-ETP CW004A) procured from LME-certified copper refineries. Copper purity ≥99.90%, conductivity ≥98% IACS, density 8.94 g/cm³, and thermal conductivity 388 W/m·K. The high purity ensures that even at the large cross-sections used in HV terminations (240–630 mm²), the lug introduces no measurable thermal discontinuity at the cable-lug junction. Material traceability is maintained via heat number, chemical analysis report (EN 10204 3.1), and batch segregation throughout production.

Crimping Technology for Long Barrel Lugs

Long barrel lugs for MV/HV applications are crimped with hydraulic compression tools using hexagonal dies (per IEC 61238-1 / DIN 46235 / BS 8537) or indent dies. For sizes from 16 to 240 mm², hand-held hydraulic crimp tools (8–12 ton) with the appropriate die profile and die cross are used. For 300–630 mm², benchtop 12–20 ton hydraulic presses with calibrated die sets are required. The number of crimps per barrel (2–6 crimps) and crimp sequence (from conductor end toward palm) are specified by EAI in the installation instruction sheet supplied with each lug batch. Proper crimping achieves a contact resistance ≤1.2× the cable conductor resistance over 1 m per IEC 61238-1.

Palm / Tongue Design for Transformer & Switchgear Terminals

The palm of long barrel lugs follows DIN 46235 or custom OEM dimensions for attachment to power transformer HV/LV terminal pads, switchgear bushing terminals, generator output terminals, and motor cable box lugs. Palm thickness, bolt-hole diameter (M10 to M24 for large conductors), and two-hole vs. single-hole configurations are selected based on the terminal stud specifications of the connected equipment. EAI manufactures custom palm geometries against OEM drawings for transformer manufacturers including ABB, Siemens, BHEL, Crompton Greaves, and local transformer OEMs.

Tin Plating, Nickel Plating & Silver Plating Options

Standard finish is bright bare copper with anti-tarnish lacquer. For tropical, coastal, and aggressive industrial environments, tin plating (bright tin, 10–15 µm, electrolytic) prevents cupric oxide formation at the lug-conductor interface and at the palm-terminal contact. Tin-plated long barrel lugs are standard specification for many utility procurement authorities. Nickel plating (5–10 µm) extends service temperature to 200°C. Silver plating (2–5 µm) is specified for HV compressed gas insulated switchgear (GIS) bushing connections where contact resistance must be minimized and remain stable over 30-year service life. All plating conforms to IEC 60068-2-11 salt spray test requirements.

Inspection Oil-Fill & Sealed Barrel Variants

For submarine cable and underground HV cable applications, long barrel lugs with sealed barrel tips (blind-ended barrel) prevent moisture ingress into the cable conductor under the lug. When crimped, the sealed end forms a gas-tight barrier. This is required by cable standards for some 110–220 kV XLPE cable systems where partial discharge (PD) testing of the completed joint must not be compromised by moisture at the lug-conductor interface. EAI manufactures sealed/blind-barrel long barrel lugs for submarine cable contractors and HV cable joint manufacturers.

Linked Products & Related Parts

Copper long barrel tubular lugs are used with: heat-shrink termination kits (IEC 60502-4), cold-shrink cable termination accessories, cable glands, transformer terminal pads, copper mechanical lugs, copper ring type lugs, copper stamped transformer lugs, cable screens connectors, earth continuity connectors, and SF6 switchgear bushing bolts.

Key Features

• Extended barrel length: 1.5×–2.5× standard DIN 46235 barrel for MV/HV cable accessory systems
• Conductor range: 16 mm² to 630 mm² (IEC 60228 Class 1, 2; stranded & solid)
• ETP copper C11000 / IS 1897: ≥99.90% Cu, ≥98% IACS conductivity
• Voltage capability: 6 kV to 220 kV (with appropriate HV insulation accessories)
• Palm dimensions: DIN 46235 / BS 4579 standard or custom OEM dimensions
• Bolt-hole sizes: M10, M12, M16, M20, M24
• Surface options: bare copper, tin-plated, nickel-plated, silver-plated
• Sealed (blind) barrel variants available for submarine and underground HV cables
• Compliant: IEC 61238-1, DIN 46235, BS 4579, IS 8309, IEC 60502-4
• Price: US$16.80/kilogram

Compatibility with HV Cable Accessory Systems

Long barrel lugs are a component of complete MV/HV cable termination kits supplied by Raychem (TE Connectivity), 3M, Nexans Euromold, Cellpack, GECA, and Prysmian group. These systems specify exact barrel length, bore diameter, and surface finish requirements for their heat-shrink or cold-shrink insulation kits. EAI has developed a comprehensive database of 500+ lug-accessory combinations and can manufacture lugs to any system manufacturer’s dimensional drawing within standard lead times. This makes EAI a preferred OEM supplier to cable accessory distribution companies and electrical utilities worldwide.

Superior Conductor Engagement & Crimped Joint Integrity

The longer barrel provides a larger conductor-crimp interface area. For a 240 mm² conductor, doubling barrel length from 76 mm to 150 mm approximately doubles the crimped joint contact area, reducing joint resistance and improving current-carrying capacity of the termination to match the cable’s ampacity rating. Per IEC 61238-1, type-tested long barrel lugs demonstrate contact resistance ≤1.2× cable resistance and survive 1000 heat cycles (ΔTMAX 100°C) without increase in resistance. This ensures the termination does not become a thermal hot spot in the distribution network.

Precision CNC Machined Bore

The barrel bore of long barrel lugs is CNC-drilled to H7 tolerance: for conductor sizes up to 70 mm², bore tolerance is ±0.05 mm; for 95–630 mm², ±0.10 mm. This precision ensures that the conductor fits the bore without excessive clearance (which would reduce compression efficiency) or interference fit (which would prevent conductor insertion). Bore surface roughness is Ra ≤3.2 µm to maximize grip on the conductor wires during crimping. The bore entry is chamfered at 15° to facilitate conductor insertion without conductor wire damage.

OEM Supply to Transformer & Switchgear Manufacturers

Power transformer manufacturers require lugs that interface precisely with their terminal pad design: palm size, bolt hole pattern, tongue thickness, and angular palm offset are defined in transformer terminal assembly drawings. EAI supplies transformer-specific long barrel lugs to transformer OEMs as a managed component with part number, dimensional drawing, and material certificate traceable to each transformer’s production record. The same supply capability extends to GIS and AIS switchgear manufacturers who procure lugs as part of their type-tested switchgear panel assembly.

Utility-Grade Quality Assurance

For power utility procurement (state electricity boards, regional transmission organizations, distribution companies), EAI provides: pre-qualification testing reports per IEC 61238-1, type test certificates, factory inspection access, independent third-party test reports from NABL-accredited laboratories, and material test certificates (EN 10204 3.1). Utility procurement specifications (RDSO drawings for Indian railways, CEA specifications, DISCOMS tender specifications) are assessed and matched at the quotation stage, with any special requirements identified and addressed before production.

Technical Specifications

Raw Material Grades & International Equivalents

Product Types & Variants

Applications in Industry

Manufacturing Process

Copper Long Barrel Tubular Lugs are manufactured through a precision subtractive machining process from ETP copper rod. Stage 1 – Rod Inspection: ETP copper rod (IS 1897/ASTM B187) is incoming-inspected for chemical composition (XRF analysis), diameter, straightness, and surface quality. Stage 2 – CNC Bar Turning: Copper rod is chucked in CNC turning centres and turned to the lug blank outer diameter with the barrel OD and shoulder profile formed in the same operation. Stage 3 – Barrel Boring: The barrel bore is CNC-drilled to the specified inner diameter, depth, and H7 tolerance using carbide-tipped drills and boring bars. The bore entry chamfer (15°) is cut in the same setup. For sealed/blind barrel variants, the bore depth is set to leave a copper wall of 2–3 mm at the sealed end. Stage 4 – Palm Milling & Drilling: The palm is CNC-milled to thickness, drilled with bolt holes (M10–M24), and deburred. Two-hole palms have bolt-hole pitch matching DIN 46235 or custom OEM dimensions. Stage 5 – Surface Preparation: Parts are alkaline-cleaned, pickled in dilute H₂SO₄, neutralized, and rinsed. Stage 6 – Surface Treatment: Bare lugs are lacquer-coated. Tin/nickel/silver plating is applied in barrel-plating or rack-plating lines to specified thickness with thickness monitoring by XRF. Stage 7 – Final Inspection & Marking: CMM dimensional inspection (bore diameter, depth, palm dimensions, bolt-hole position), contact resistance measurement, visual AQL 1.0, and marking (size, material, batch). Stage 8 – Packing: Lugs are packed individually in polybags or in bulk cartons with foam inserts for large sizes. Shipping marks include conductor size, palm bolt-hole size, finish, and batch/MTC reference.

Quality Standards & Certifications

Why Choose Electrical Accessories India

• Specialist MV/HV lug manufacturer with 35+ years supplying Indian and international utilities
• CNC turning/boring capability for precise H7 bore tolerances in long barrels up to 220 mm length
• OEM dimensional drawings accepted — 500+ cable accessory system configurations in database
• Sealed/blind barrel option for submarine and underground HV cable applications
• Silver plating capability for GIS bushing connections (2–5 µm Ag per rack-plating process)
• ISO 9001:2015 certified; EN 10204 3.1 MTCs on every shipment; NABL-accredited third-party test reports available
• Export to power utilities, transformer OEMs, and cable accessory companies in 30+ countries
• Pricing: US$16.80/kg; MOQ 50 kg per size

Frequently Asked Questions

Q1. What is the difference between a long barrel lug and a standard tubular lug?

A long barrel lug has an extended barrel (1.5×–2.5× the length of a standard DIN 46235 lug for the same conductor size). The longer barrel is required for MV/HV cable termination systems where insulation accessories must overlap the bare copper barrel by a defined length to maintain creepage and clearance distances. Standard barrel lugs are for LV (<1 kV) applications only.

Q2. For which voltage levels are long barrel lugs required?

Long barrel lugs are typically required for cable systems from 6 kV (6.6 kV) upward. Below 1 kV, standard DIN 46235 or short barrel lugs are used. The exact barrel length required for 6 kV, 11 kV, 22 kV, 33 kV, 66 kV, 110 kV, and 220 kV is defined by the cable accessory manufacturer’s installation instructions for the specific termination kit series.

Q3. What is the price of copper long barrel tubular lugs?

Long barrel copper lugs are priced at US$16.80 per kilogram. Due to the extended barrel length, long barrel lugs are heavier than standard lugs for the same conductor size, and therefore slightly higher cost per unit. Contact EAI for a size-wise price list and per-unit weight table.

Q4. Can EAI manufacture long barrel lugs to a cable accessory manufacturer’s drawing?

Yes. EAI maintains an OEM drawing database covering 500+ cable accessory system configurations from Raychem (TE Connectivity), 3M, Nexans Euromold, Prysmian, Cellpack, and others. New drawings are tooled within standard lead times of 4–6 weeks from drawing approval.

Q5. Are sealed (blind-end) barrel lugs available for submarine cable applications?

Yes. EAI manufactures sealed/blind barrel long barrel lugs with a solid copper wall at the barrel end (2–3 mm minimum thickness). The sealed end prevents moisture ingress into the conductor under the lug and is required for some 110–220 kV submarine cable systems and direct-buried cable installations where the partial discharge test on the completed joint must not be affected by moisture.

Q6. What plating is recommended for GIS bushing connections?

Silver plating (2–5 µm) is recommended for connections to SF6 Gas Insulated Switchgear (GIS) bushings. Silver plating provides stable low contact resistance over the 30-year GIS service life and prevents fretting corrosion at the palm-bushing interface. Tin plating is used for standard AIS and transformer connections. Nickel plating is used in high-temperature or marine environments.

Q7. What crimp tools are recommended for long barrel lugs in the 240–630 mm² range?

For 240–630 mm², a benchtop hydraulic press with 12–20 ton capacity and hexagonal or indent die sets (per DIN 46235 or manufacturer specification) is required. Multiple crimp operations (3–6 crimps) are needed per barrel, starting from the conductor end and progressing toward the palm. EAI provides a crimping parameter sheet (number of crimps, die reference, crimp force) with each large-conductor lug shipment.

Q8. What is the minimum order quantity?

MOQ is 50 kg per size/finish combination. For HV cable accessory OEM supply, project-specific quantities are quoted against the project bill of materials. Sample orders (5 kg per size) are accepted for type testing.

Q9. Are material test certificates (3.1 MTC) provided?

Yes. EN 10204 Type 3.1 material test certificates covering chemical composition (Cu, Pb, Bi, etc.) and mechanical properties (tensile strength, elongation) of the raw copper rod are provided standard on every commercial shipment. NABL-accredited third-party chemical analysis reports are available on request.

Q10. What international equivalent standards cover long barrel lugs?

IEC 61238-1 (Part 1 and Part 2), DIN 46235 (extended barrel dimensions), BS 4579, IS 8309, and IEC 60502-4. National utility specifications (CEA India, RDSO India, BS EN 62067, IEC 60840) may additionally apply depending on the end application voltage and country.

International Equivalent Terms

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Request a Quote

Contact Electrical Accessories India for pricing and specifications on Copper Long Barrel Tubular Lugs. Specify conductor size (mm²), required barrel length (or cable accessory system reference), palm bolt-hole size, palm configuration, surface finish, and quantity. Project-specific pricing for utility tenders and transformer OEM supply available.

Jamnagar, Gujarat, India | Export to USA, Europe, Middle East, Africa, Southeast Asia | Price: US$16.80/kg

📧 Email: info@elecaccs.com | 🌐 Contact Us

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