Brass Bushing & Connection Hardware Used in Transformer Assemblies

In power and distribution transformers, bushing and connection hardware forms a critical interface between electrical conductors, insulation systems, and the transformer tank. These components must maintain reliable electrical conductivity, mechanical strength, and sealing integrity while operating under thermal cycling, vibration, and long service life expectations.

Brass remains a widely used material for such hardware due to its balance of conductivity, corrosion resistance, machinability, and dimensional stability.

Typical Brass Components Used in Transformer Bushings

Transformer OEMs commonly specify custom-machined brass parts, manufactured strictly as per drawings, including:

• Bushing flanges and mounting rings

• Threaded brass bushings and adapters

• Terminal interfaces and connector blocks

• Earthing lugs and grounding hardware

• Sealing-related rings, inserts, and collars

These components are usually integrated with porcelain or composite bushings and must align precisely with insulation clearances and sealing surfaces.

Why Brass Is Preferred for Bushing Hardware

Brass offers several advantages in transformer applications:

• Good electrical conductivity suitable for current-carrying interfaces

• Excellent corrosion resistance, particularly in oil-filled and outdoor environments

• Stable machining behavior, allowing tight tolerances and repeatability

• Compatibility with sealing systems, reducing galling and surface damage

Depending on the application, different brass grades may be specified to meet mechanical or conductivity requirements.

Manufacturing Considerations for Transformer OEMs

Bushing and connection hardware is rarely a catalog item. Most transformer manufacturers require:

• Manufacturing strictly to approved drawings

• Controlled tolerances on mating and sealing surfaces

• Burr-free edges to avoid insulation damage

• Consistent surface finish for electrical and sealing performance

• Full material traceability with test certificates

First Article Inspection (FAI) is typically required before serial production, especially for HV applications.

Batch Sizes and Supply Expectations

Transformer programs often involve low to medium batch sizes, with repeat orders over long product life cycles. Suppliers must be capable of supporting:

• Engineering revisions

• Prototype and pre-series quantities

• Stable repeat production for approved parts

Consistency across batches is often more critical than high-volume output.

Brass bushing and connection hardware plays a vital role in transformer reliability and safety. Precision machining, correct material selection, and strict adherence to drawings are essential to ensure long-term performance in demanding electrical environments.

For transformer OEMs, partnering with manufacturers experienced in custom, drawing-based brass components helps ensure reliability, compliance, and continuity of supply throughout the product lifecycle.