Copper Threaded Transformer Studs – Manufacturer and Exporter from India
Cable Glands India manufactures and exports Copper Threaded Transformer Studs – precision-machined, high-conductivity copper studs designed for transformer terminal connections, bus bar bolting, and electrical switchgear applications. Our copper transformer studs provide reliable, low-resistance electrical contact at transformer HV and LV bushings, tap changer terminals, and distribution board bus bar connections. Available in metric, BSP, UNC, and UNF threads with custom lengths and configurations.
What Are Copper Threaded Transformer Studs?
Copper threaded transformer studs are cylindrical copper fasteners with threads on one or both ends, used to mechanically and electrically connect cable lugs, bus bars, and terminal fittings to transformer bushings and switchgear terminals. They are installed by threading into tapped holes in transformer bushings or bus bar blocks, and are used with copper or brass nuts and washers to complete the electrical joint. The use of high-conductivity copper ensures minimum contact resistance and efficient power transfer at transformer terminals.
Types of Copper Threaded Transformer Studs
- Single-Ended Stud – Threaded on one end for insertion into tapped bushing holes; plain shank on the other end
- Double-Ended Stud – Threaded on both ends for use with two nuts; ideal for connecting two conductors through a terminal block
- Stepped Stud – Different thread sizes on each end; for connecting metric bus bars to inch-thread bushings
- Flanged Stud – With an integral flange for positive stop positioning in transformer bushings
- NEMA Spacing Transformer Stud – Pre-drilled or tapped to NEMA (1/2 inch, 5/8 inch, 3/4 inch) spacing for North American transformers
- Bi-Metallic Transformer Stud – Copper body with aluminum threaded end for connecting aluminum conductors to copper terminals
Key Features and Specifications
- Material: Electrolytic Tough Pitch (ETP) Copper (99.9% Cu), Deoxidized High Phosphorus (DHP) Copper, or Oxygen-Free Copper (OFC)
- Thread Standards: Metric (M6 to M48), BSP, UNC (1/4 inch to 2 inch), UNF, and custom threads
- Length Range: 20 mm to 500 mm (custom lengths available)
- Diameter Range: 6 mm to 60 mm
- Surface Finish: Bare copper, Electro-tinned, Silver-plated, or Nickel-plated
- Conductivity: 98-101% IACS depending on grade
- Standards: ASTM B152, ASTM B187, BS EN 13601, IS 613, IS 1897, IEC 60317
- Temperature Rating: Up to 105 degrees C continuous (bare copper); up to 150 degrees C (silver-plated)
Technical Specifications – Copper Threaded Transformer Studs
| Thread Size | Stud Diameter | Length Range | Current Rating | Surface Finish |
|---|---|---|---|---|
| M10 | 10 mm | 25-100 mm | Up to 100 A | Bare or Tinned |
| M12 | 12 mm | 30-120 mm | Up to 150 A | Bare or Tinned |
| M16 | 16 mm | 40-150 mm | Up to 250 A | Bare or Silver-plated |
| M20 | 20 mm | 50-200 mm | Up to 400 A | Bare or Silver-plated |
| M24 | 24 mm | 60-250 mm | Up to 600 A | Silver-plated |
| M30 | 30 mm | 80-300 mm | Up to 900 A | Silver-plated |
| M36 | 36 mm | 100-400 mm | Up to 1400 A | Silver-plated |
| 1/2 inch UNC | 12.7 mm | 30-150 mm | Up to 200 A | Tinned or Silver |
| 5/8 inch UNC | 15.9 mm | 40-200 mm | Up to 350 A | Tinned or Silver |
| 3/4 inch UNC | 19.1 mm | 50-250 mm | Up to 500 A | Tinned or Silver |
Copper Material Grades Used in Transformer Studs
| Grade | ASTM Standard | BS or IS Standard | Conductivity | Best For |
|---|---|---|---|---|
| ETP Copper (Cu-ETP) | ASTM B152 / UNS C11000 | BS EN 13601 / IS 613 | 100% IACS | Standard transformer studs for all voltage levels |
| DHP Copper (Cu-DHP) | ASTM B152 / UNS C12200 | BS EN 12449 / IS 7608 | 97% IACS | Welding-friendly studs for fabricated transformer terminals |
| Oxygen-Free Copper (Cu-OF) | ASTM B170 / UNS C10100 | BS EN 13600 / IS 13573 | 101% IACS | High-performance, low-loss transformer connections |
| Tinned ETP Copper | ASTM B246 | BS EN 13602 | 97% IACS | Coastal and outdoor substation transformers |
| Silver-Plated Copper | ASTM B700 | BS EN 14825 | 98% IACS | High-temperature transformer terminals and HV substation |
Applications of Copper Threaded Transformer Studs
- Distribution transformer LV and HV bushing terminal connections
- Power transformer tap changer terminal connections
- Bus bar bolted joint connections in HV and LV switchgear panels
- Earthing terminal connections on transformer tanks and enclosures
- Auto-transformer and reactor terminal connections
- MV and LV switchgear terminal block connections
- Renewable energy transformer terminal connections for solar and wind projects
- Current transformer and potential transformer terminal connections
- Industrial furnace transformer and rectifier transformer connections
Why Choose Cable Glands India for Copper Threaded Transformer Studs?
- Manufactured from premium ETP copper (100% IACS) to ASTM B152, BS EN 13601, IS 613 standards
- Available in all standard thread forms: Metric, BSP, UNC, UNF, and custom configurations
- Full size range: M6 to M48 metric, lengths up to 500 mm
- Silver-plated and tinned variants for high-temperature and coastal environments
- Bi-metallic studs for aluminum-to-copper transformer terminal connections
- In-house CNC machining, thread gauging, conductivity testing, and dimensional inspection
- Material test certificates (MTC), dimensional reports, and third-party inspection available
- Fast global delivery to UK, USA, UAE, Australia, South Africa, Southeast Asia and Middle East
Frequently Asked Questions
What is the difference between a Copper Transformer Stud and a Brass Stud?
Copper transformer studs offer significantly higher electrical conductivity (100% IACS) compared to brass (typically 26-27% IACS), making them essential for high-current transformer terminal connections where minimizing contact resistance and heating is critical.
Why is silver plating used on copper transformer studs?
Silver plating prevents copper oxide formation on the contact surface which would increase contact resistance. Silver-plated studs maintain consistent low contact resistance over the transformer service life, especially at high operating temperatures up to 150 degrees C typical in power transformers.
What thread type is used for transformer studs in Indian and UK projects?
In India, metric threads (IS 1897) are standard for transformer bushing connections. In UK and Commonwealth projects, BSP threads are also common. We supply both metric and BSP threaded transformer studs and can manufacture to NEMA spacing requirements for North American transformers.
Can you supply copper transformer studs with bi-metallic ends for aluminum conductors?
Yes. We supply bi-metallic copper-aluminum transformer studs where one end has a copper thread for the transformer bushing and the other end has an aluminum thread or compression sleeve for the aluminum cable lug. This eliminates galvanic corrosion at the copper-aluminum interface.
Get a Quote for Copper Threaded Transformer Studs
Ready to source high-conductivity Copper Threaded Transformer Studs for your transformer or switchgear project? Contact our engineering team today with your specifications – thread size, length, copper grade, surface finish (bare, tinned, silver-plated), quantity, and delivery requirements. Our technical team will respond with recommendations and a competitive quote.
Email: sales@cableglandsindia.com
Phone: +91-22-43449300 or +91-22-43449323