Terminal Board: Wire Size Range 0.5 mm² to 150 mm²

Component Specifications

Definition

A terminal board, also known as a terminal block or connection strip, is a modular, insulated device used in electrical systems to create secure, organized connections between multiple wires. In industrial applications like main transformers, it provides a centralized point for connecting incoming and outgoing circuits, facilitating maintenance, testing, and circuit modifications while ensuring electrical isolation and safety.

Working Principle

The terminal board operates by providing metal terminals (usually made of copper or brass) embedded in an insulating base (typically thermoplastic or thermoset material). Wires are secured to these terminals via screws, clamps, or spring mechanisms, establishing electrical continuity between connected circuits while preventing short circuits and maintaining proper insulation resistance.

Materials

Base: Polyamide (PA66), phenolic resin, or polycarbonate with UL94 V-0 flame retardant rating. Terminals: Electrolytic copper (Cu-ETP) or brass with tin or nickel plating for corrosion resistance. Screws: Steel with zinc or chrome plating.

Technical Parameters

Parameter	Typical range	Notes & selection driver
IP Rating	IP20 (standard) to IP67 (protected)
Mounting Type	DIN rail (TS35/TS32), panel, or PCB
Current Rating	10A to 300A
Voltage Rating	Up to 1000V AC/DC
Wire Size Range	0.5 mm² to 150 mm²
Dielectric Strength	3000V AC for 1 minute
Insulation Resistance	>1000 MΩ
Operating Temperature	-40°C to +120°C

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 9001, IEC 60947-7-1, UL 1059, DIN 46277

Parent Products

This component is used in the following industrial products

Main Transformer

The primary voltage transformation component in a rectifier power supply system that steps down or steps up AC voltage to the required level before rectification.

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Engineering Analysis

Risks & Mitigation

Electrical shock from exposed terminals
Overheating due to loose connections or overcurrent
Short circuits from insulation failure
Corrosion leading to increased resistance

FMEA Triads

Trigger: Loose terminal screws due to vibration or improper torque
Failure: Increased contact resistance leading to overheating and potential fire
Mitigation: Use spring-clamp terminals, apply correct torque during installation, and implement regular maintenance checks

Trigger: Moisture ingress or chemical exposure
Failure: Corrosion of terminals, reduced conductivity, and insulation breakdown
Mitigation: Select IP-rated or sealed terminal boards, use protective coatings, and control environmental conditions

Trigger: Overloading beyond current rating
Failure: Melting of insulation, terminal damage, and circuit failure
Mitigation: Properly size terminal boards for expected load, install overcurrent protection devices, and monitor operating conditions

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Terminal position tolerance ±0.5mm, screw torque tolerance ±10% of specified value

Test Method

Dielectric strength test per IEC 60947-7-1, current carrying capacity test at rated current until thermal equilibrium, insulation resistance test at 500V DC

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

Check the legal entity, factory address, ownership, certifications, and direct contacts.

CNFX does not score or rank suppliers. Buyers must verify all claims and documents with the legal manufacturer before ordering.

Manufacturers of Terminal Board

Manufacturer profiles associated with Terminal Board.

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Related Components

Terminal Base

A terminal base is an insulating support structure that holds and organizes electrical terminals in motor terminal blocks, providing secure connections and circuit management.

Contact Plate

A conductive plate in motor terminal blocks that establishes electrical contact between conductors.

Marking Strip

A durable marking strip used for terminal identification in motor terminal blocks to ensure proper electrical connections and safety compliance.

Gland Body

A gland body is the main housing component of an aluminum cable gland that provides mechanical protection and environmental sealing for electrical cables entering enclosures.

Frequently Asked Questions

What is the difference between a terminal board and a terminal block?

A terminal board typically refers to a larger assembly with multiple terminals mounted on a single base, often used in panels, while a terminal block is a modular single unit that can be combined on a DIN rail. In practice, the terms are often used interchangeably.

How do I select the right terminal board for a main transformer?

Consider the transformer's voltage and current ratings, environmental conditions (temperature, humidity), required safety certifications (e.g., UL, IEC), wire sizes, and mounting method. Always consult the transformer manufacturer's specifications.

Can terminal boards be used in high-vibration environments?

Yes, but choose models with vibration-resistant features like spring-clamp terminals, locking screws, or additional securing brackets to prevent loosening.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Terminal Board