Transformer Spade Terminals, Transformer Spade Connectors / Material and connection variants

C37700 Forged Brass Transformer Spades

C37700 forged brass transformer spades combine a forged copper-zinc-lead alloy body with machined terminal features. Cable Glands India offers straight inline configurations with NEMA-spaced palms for pad-mounted transformers, finished naturally or with tin plating to the purchase specification.

Price on request. Quotation depends on the approved alloy, geometry, finish and order quantity.

Product overview

Forging Brass Grade C37700

C37700 is a wrought forging-brass grade. It should not be described or ordered as a C83300, C83600 or C84400 bronze casting. Its copper, lead and zinc composition is specified for the material family, while the finished part requirements depend on the forging condition and machining drawing. Use the formal UNS designation to identify the alloy. International brass names with similar nominal chemistry require technical comparison before they can be accepted as substitutes.

Forged Blank to Finished Transformer Spade

The manufacturing route starts with suitable forging stock and a die design appropriate to the terminal geometry. The forged blank is trimmed and prepared before critical features are machined. The drawing should distinguish as-forged surfaces from finished contact faces and threads. Die parting lines must not interfere with seating or assembly. Hub-to-palm transitions, machining allowance and final dimensions should be reviewed together during part development. Forging does not remove the need for inspection of the completed terminal.

Selection Against Electrical and Mechanical Duty

C37700 may be specified where the transformer design calls for a forged brass terminal. The manufacturing process alone does not demonstrate electrical equivalence to an ETP copper spade or a cast-bronze design. Confirm the allowed material, current duty, joint configuration and mechanical loads. Natural and tin-plated finishes are available to specification, with thread fit checked in the final condition. Replacement enquiries should identify the existing material and geometry rather than choosing solely by appearance.

Key features

• UNS C37700 / CDA 377 forging brass material specification for traceable procurement.
• NEMA-spaced palm for compatible bolted terminal layouts.
• Natural and tin-plated finish options.
• Straight connection geometry for the specified transformer arrangement.
• Machined contact surfaces, bores and threads to an approved drawing.
• Configuration review for electrical OEMs, EPC contractors, power utilities and distributors.

NEMA palm and bolted contact interface

The palm provides the contact area between the transformer connector and the mating lug or busbar. Hole spacing supports interchangeability only when hole diameter, edge distance, palm thickness and terminal orientation also agree. Confirm access for sockets and spanners in the enclosure. A greater number of holes does not automatically permit a higher current or a larger number of independent outgoing circuits. The assembled connection and conductor arrangement govern the operating duty.

Natural metal and tin-plated contact surfaces

Natural finish retains the appearance of the selected base material. Tin plating provides a different surface condition for the specified joint design and handling environment. Specify preparation, coating thickness and coverage before manufacture. Threads may require allowance or masking to preserve fit after plating. Evaluate the complete joint when connecting dissimilar metals, including the conductor, lug, fasteners and environmental exposure. Do not assume that tin plating alone establishes aluminum-conductor compatibility.

Stud fit and dimensional control

The stud connection must match both the nominal size and the detailed thread designation. Pitch, class of fit, usable thread depth and entry chamfer affect assembly. Check shoulder contact and available engagement against the bushing drawing. Incorrect thread combinations can appear to start and still damage the mating terminal. Use the OEM installation procedure and specified tightening torque; neither the alloy name nor a catalog illustration defines a safe torque setting.

Technical specifications

Material composition and international designations

Composition values are weight percentages where shown. The governing purchase specification and material certificate determine acceptance, including any residual-element limits not reproduced here.

Product variants

Industrial applications

C37700 Forged Brass Transformer Spades are intended for the terminal connection zone of pad-mounted transformers. They can form part of an OEM bushing-to-lug or stud-to-palm assembly, subject to the transformer design. Utilities use approved connector configurations for equipment replacement and maintenance programs. EPC contractors specify the terminal interface alongside cables, lugs, busbars and installation hardware. Distributors should identify the actual material and thread arrangement so that a visually similar part is not supplied as an unapproved replacement.

For retrofit work, check the existing terminal drawing, enclosure clearance and conductor approach before ordering. Confirm corrosion exposure, operating temperature and fault duty with the equipment owner. Installation and maintenance should follow the applicable equipment instructions with the system isolated and made safe.

Manufacturing process

1. Confirm C37700 forging stock, finished condition and drawing.
2. Develop the forging blank and establish machining allowances.
3. Hot forge the approved blank and trim flash as required.
4. Prepare the forging and inspect drawing-critical regions.
5. Machine contact faces, NEMA-spaced holes and the specified stud thread.
6. Deburr, clean, finish naturally or tin plate, and inspect the completed spade.

Production release should connect the drawing revision to the material lot, machining setup and inspection plan. Changes to palm thickness, bore geometry or hole layout can affect both mechanical fit and the thermal performance of the assembled joint. Agree first-article checks for a new design before repeat quantities are released. Pack contact surfaces to limit damage during transport and keep natural and plated batches clearly identified.

Quality standards and documentation

NEMA spacing describes the mounting interface; it is not a standalone certification of the finished connector. Standards listed here are specification references to be agreed for the order. No universal UL listing, IEC approval, ISO certification or blanket environmental-compliance claim is implied for every custom variant. If regulated-substance requirements apply, identify the destination market and required declaration before selecting a lead-containing alloy.

Why choose Cable Glands India

This product range brings material selection, connection geometry and finish into one drawing-based inquiry. Buyers can compare bronze, copper, forged brass and cast brass versions within the same transformer terminal family. A clear specification helps procurement teams obtain comparable quotations and helps engineering teams separate material identity from assembly performance. State the required inspection records, marking and packaging at the quotation stage so the supply scope is reviewable before manufacture.

Questions and answers

Is C37700 a casting grade?

C37700 is a wrought forging-brass designation. This product uses a forged and machined route. A brass casting must be specified under an appropriate cast-alloy grade instead.

Are these connectors suitable for pad-mounted transformers?

They are intended for pad-mounted transformer terminal connections where the approved bushing, stud, palm, conductor and enclosure arrangement matches the connector drawing. Confirm electrical duty, clearances and mechanical loading with the transformer OEM before release.

Are the mounting holes NEMA spaced?

Yes. The palm uses a NEMA-spaced mounting arrangement. Specify the exact hole count, center-to-center dimensions, hole diameter and orientation on the order drawing; the phrase NEMA spaced alone is not a complete interface specification.

Can I order natural and tin-plated finishes?

Yes. Both natural metal and tin-plated finishes can be specified. State coating thickness, coverage, masking, contact-surface requirements and inspection criteria. Tin plating does not change the underlying alloy designation.

Which stud threads can be supplied?

The family includes nominal 3/8, 1/2, 3/4 and 1 inch stud interfaces, with UNC, UNF, UNEF or UNS forms where the drawing requires them. Confirm diameter, pitch, class, engagement length and thread direction; not every diameter uses every series as a standard combination.

What is the current rating?

There is no single current rating for all geometries. The assembled connection must be assessed for conductor size, contact area, temperature rise, installation torque and fault duty. Request the test requirements for your approved design instead of selecting by alloy or hole count alone.

Are installation bolts and washers included?

Specify the complete hardware bill of materials in the inquiry. Inclusion, bolt material, coating, washer arrangement and approved tightening torque must be confirmed for the supplied assembly.

Can a similar international alloy be substituted?

Use the specified grade and product form as the procurement baseline. A proposed substitute needs a comparison of chemistry, mechanical properties, conductivity, casting or wrought condition and the governing standard, followed by customer approval.

What information is needed for a quotation?

Send the drawing and revision, alloy, quantity, stud thread, palm dimensions, NEMA hole pattern, finish, inspection documents and delivery destination. Identify prototype quantities separately from repeat production requirements.

Related transformer terminals and connectors

• C83300 Bronze Terminal Spades for Transformers
• C84400 Bronze Spade Connectors
• C83600 Transformer Spade Terminals
• Copper ETP Transformer Spade Connectors
• Transformer Spade Terminals from Brass Casting
• Bronze Stud Connectors for Transformers