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Product Details
Transformer Spade Connectors of Bronze
Bronze Transformer Spade Connectors — Manufacturer & Exporter from India
Electrical Accessories India manufactures and exports precision-machined bronze transformer spade connectors from Jamnagar, Gujarat — India’s foremost hub for non-ferrous precision components. These fork-terminal connectors are engineered for bolted connections on power transformer bushings, tank earthing points, substation bus bars, and switchgear terminals. Manufactured from high-conductivity bronze alloys (C95400, C83600, C90500), our spade connectors meet IEC 61238-1, IS 5561, and BS 4579 requirements, and are supplied to electrical OEMs, EPC contractors, power utilities, and distributors across 30+ countries.
Product Overview
A transformer spade connector — also referred to as a bronze fork terminal, bronze spade lug, or bronze tongue connector — is a flat, slotted terminal fitting that slides over a stud or bolt for quick, secure electrical connections. Unlike compression lugs that require crimping, spade connectors provide tool-reducible, inspectable connections with consistent contact force determined by bolt torque. In transformer applications, the bronze material is specified because it resists oxidation, maintains low contact resistance over decades of service, and withstands the thermal cycling inherent in transformer loading cycles. Electrical Accessories India produces these connectors through a combination of hot forging, CNC turning, and precision drilling on IS-1570 and UNS-designated bronze bar stock, ensuring dimensional repeatability for high-volume OEM supply.
Key Features
- High electrical conductivity: Bronze alloys C95400 and C83600 provide conductivity of 7–15% IACS, acceptable for high-current bus connections while maintaining structural rigidity.
- Corrosion resistance: Inherent bronze oxidation resistance; optional tin or nickel plating for aggressive industrial and coastal environments.
- Thermal stability: Operating temperature range −40°C to +120°C continuous; compatible with transformer oil environments.
- Spade/fork geometry: Open-slot design enables connection and disconnection without full bolt removal — critical for live-adjacent maintenance operations.
- Multiple bore sizes: Available in conductor cross-sections from 16 mm² to 630 mm² with stud holes M8 to M36.
- CNC-machined contact surfaces: Flat contact face machined to Ra ≤ 3.2 µm for uniform current distribution.
- RoHS-compliant material options: Lead-free bronze grades available on request for European export compliance.
- Custom OEM dimensions: Full reverse engineering from customer drawings or samples.
Technical Specifications
| Parameter | Specification |
|---|---|
| Material | Bronze: C95400 / C83600 / C90500 / C86300 |
| Conductor Size Range | 16 mm² – 630 mm² |
| Stud Hole Diameter | M8, M10, M12, M16, M20, M24, M30, M36 |
| Current Rating | 100A – 1000A (conductor-dependent) |
| Voltage Rating | Up to 36 kV (system voltage) |
| Operating Temperature | −40°C to +120°C |
| Surface Finish | Natural / Tin-plated (5–15 µm) / Nickel-plated |
| Contact Resistance | ≤ 10 µΩ (at rated torque) |
| Torque (M12 stud) | 25–35 Nm |
| Manufacturing Process | Hot forging + CNC machining |
| Country of Origin | India (Jamnagar, Gujarat) |
Bronze Alloy Grades & International Equivalents
| Grade (UNS) | Common Name | IS (India) | BS (UK) | DIN (Germany) | JIS (Japan) | Tensile Strength |
|---|---|---|---|---|---|---|
| C83600 | Leaded Red Bronze / 85-5-5-5 | LTB-1 | PB1 | 2.1090 | BC6 | 241 MPa |
| C90500 | Gun Metal / Tin Bronze | LTB-2 | PB2 | 2.1050 | BC2 | 276 MPa |
| C95400 | Aluminum Bronze | AB1 | CA104 | 2.0960 | AlBC3 | 586 MPa |
| C86300 | Manganese Bronze | HTB3 | HTB3 | 2.0560 | HBsC4 | 655 MPa |
Product Types and Variants
Electrical Accessories India supplies bronze transformer spade connectors in the following configurations:
- Standard One-Hole Spade: Single stud-hole, flat palm, for M8–M24 studs. Used on transformer LV bushing terminals.
- Two-Hole Long Barrel Spade: Extended barrel with two fixing holes for higher pull-out strength; used on HV bushing connections.
- 90° Offset Spade: Palm rotated 90° relative to barrel axis for right-angle cable entry on compact transformer tanks.
- Bi-metallic Spade (Al-Bronze): Aluminium barrel friction-welded to bronze spade; for aluminium conductor to bronze stud connections.
- Compression-Type Bronze Spade: Crimp barrel with spade tongue; for field-assembly terminations on XLPE and EPR cables.
- Flanged Spade Connector: Flange at palm for panel-mount grounding applications.
Applications in Industry
| Industry / Application | Specific Use |
|---|---|
| Power Transformers | LV and HV bushing terminal connections, neutral point earthing |
| Distribution Substations | Bus bar connections, earth bus terminations |
| Switchgear & Switchboards | Incoming and outgoing cable terminations in MV panels |
| Wind Energy | Turbine transformer LV connections, tower earthing |
| Solar Power Plants | Inverter transformer connections, combiner box earthing |
| Industrial Plants | Motor control centre (MCC) bus connections |
| Railways / Metro | Traction transformer terminations, depot earthing |
| Marine / Offshore | Shipboard transformer connections in corrosive environments |
Manufacturing Process
Our bronze transformer spade connectors are manufactured at our ISO-compliant facility in Jamnagar using the following sequence:
- Raw Material Procurement: Bronze bar/rod stock (UNS C83600, C95400) sourced from certified Indian and European foundries with full chemical composition certificates.
- Hot Forging: Billets are heated to 750–820°C and drop-forged in closed dies to produce near-net-shape blanks. Forging eliminates porosity and aligns grain structure for superior mechanical properties.
- Annealing / Stress Relief: Forged blanks are annealed at 400–500°C to relieve forging stresses and restore ductility.
- CNC Turning and Milling: Multi-axis CNC machining centres produce the palm, barrel bore, and stud slot to drawing tolerances (typically ±0.05 mm on critical dimensions).
- Drilling and Tapping: Stud holes are drilled and deburred; threaded variants are tapped to ISO 2 tolerance.
- Surface Treatment: Tin or nickel electroplating (5–25 µm) applied in-house; passivation for RoHS-compliant grades.
- Inspection and Testing: 100% dimensional inspection; electrical resistance testing on sample basis per IEC 61238-1; hardness testing per ASTM E18.
- Packaging: Polybag + corrugated box with quantity labelling; export packaging on request.
Quality Standards and Certifications
- IEC 61238-1 — Compression and mechanical connectors for power cables (1 kV–30 kV)
- IS 5561 — Electric power connectors (Bureau of Indian Standards)
- BS 4579 — Performance of mechanical and compression joints in electric cables
- IEEE 837 — Standard for qualifying permanent connections used in substation grounding
- ASTM B505 / B271 — Copper alloy continuous castings / centrifugal castings
- RoHS 2011/65/EU — Restriction of hazardous substances compliance available
- ISO 9001:2015 — Quality management system (manufacturing facility)
Why Choose Electrical Accessories India
- 30+ years of manufacturing experience in non-ferrous electrical connectors from Jamnagar, India’s precision brass and bronze hub.
- In-house CNC machining with multi-axis capability for complex geometries and tight tolerances.
- Export experience to 30+ countries including the UK, USA, Germany, Australia, South Africa, UAE, Nigeria, and Southeast Asia.
- Material traceability: Full heat-wise MTCs provided; third-party inspection (BV, SGS, TÜV) arranged on request.
- Flexible MOQ: Prototype samples to high-volume OEM supply chains.
- Technical support: Engineering team available for custom design review, application advice, and drawing approval.
Multilingual Equivalent Terms
| Language | Equivalent Terms |
|---|---|
| Spanish | Conector de paleta de bronce para transformador; Terminal horquilla de bronce; Conector tipo espada de bronce; Conector bifurcado bronce |
| Russian | Бронзовый лопаточный разъём трансформатора; Бронзовый вилочный наконечник; Бронзовый клеммный соединитель; Бронзовый плоский наконечник |
| French | Connecteur à cosse fourche en bronze pour transformateur; Borne spatule bronze; Connecteur à lame bronze; Terminal à fourche bronze |
| Portuguese | Conector espada de bronze para transformador; Terminal garfo de bronze; Conector tipo pá de bronze; Terminal bifurcado de bronze |
| Italian | Connettore a forcella in bronzo per trasformatore; Capocorda a spatola bronzo; Terminale a forcella bronzo; Connettore bronzo a paletta |
Frequently Asked Questions
What is a bronze transformer spade connector?
A bronze transformer spade connector is a fork-shaped or U-shaped terminal fitting made from bronze alloy, designed to create secure bolted connections on transformer bushings, tank walls, and substation bus bars. The spade design allows fast connection and disconnection without complete bolt removal.
Which bronze alloy grade is used for transformer spade connectors?
The most common grades are C95400 (Aluminum Bronze) for high-strength applications, C83600 (Leaded Red Bronze) for general purpose, and C90500 (Gun Metal) for corrosion-critical environments. Electrical Accessories India supplies all three grades with material test certificates.
What current rating do bronze spade connectors support?
Bronze transformer spade connectors from Electrical Accessories India support continuous current ratings from 100A to 1000A depending on cross-section area, conductor size, and alloy grade. Custom ratings are available on request.
Are bronze spade connectors suitable for outdoor and substation use?
Yes. Bronze alloys provide inherent corrosion resistance, making these connectors suitable for outdoor substations, coastal environments, and industrial yards. Optional tin or nickel plating further enhances environmental resistance.
What standards govern transformer spade connectors?
Applicable standards include IEC 61238-1, BS 4579, IS 5561 (Indian standard for electric power connectors), and IEEE 837 for permanent grounding connections.
Can these connectors be used with both copper and aluminium conductors?
Bronze spade connectors are primarily designed for copper conductors. For aluminium conductor connections, bi-metallic variants with an aluminium barrel and bronze spade body are recommended to prevent galvanic corrosion.
What is the minimum order quantity?
Electrical Accessories India accepts orders from small quantity samples for approval purposes to large OEM batch orders of 10,000+ pieces. Contact our sales team for pricing and lead times.
Do you provide dimensional drawings and material test certificates?
Yes. Dimensional drawings in PDF and DXF formats, material test certificates (MTC), and third-party inspection reports are available for all standard and custom products.
Request a Quote
For technical specifications, pricing, and lead times on bronze transformer spade connectors, contact Electrical Accessories India. Our engineering team will respond within one business day with a technical offer and dimensional drawing confirmation.
Email: sales@elecaccs.com | Tel: +91-22-43449300 | Location: Jamnagar, Gujarat, India