Terminal Screw: Torque Range 0.5 Nm to 2.5 Nm

Component Specifications

Definition

A terminal screw is a precision-engineered fastener designed specifically for electrical connections in motor terminal blocks. It functions as the clamping mechanism that physically secures wire conductors to the terminal block's conductive elements, ensuring reliable electrical contact and mechanical stability. These screws are engineered to withstand vibration, thermal cycling, and electrical current while maintaining consistent torque and contact pressure.

Working Principle

The terminal screw operates on the mechanical clamping principle. When tightened, it applies controlled pressure to compress the electrical conductor against the terminal block's contact surface, creating a low-resistance electrical path. Proper torque ensures optimal contact pressure—too little causes high resistance and overheating, while too much can damage conductors or strip threads. The screw's design often includes features like captive washers or flanged heads to distribute pressure evenly and prevent loosening from vibration.

Materials

Typically made from brass, copper alloys, or stainless steel (e.g., 304/316 SS) with optional plating (tin, nickel, or silver) for enhanced conductivity and corrosion resistance. Insulation components may use nylon or PBT.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Length	6mm to 20mm
Head Type	Pan head, flanged, or countersunk
Drive Type	Slotted, Phillips, or hex socket
Thread Size	M3 to M6 common
Torque Range	0.5 Nm to 2.5 Nm
Voltage Rating	Up to 1000V AC/DC
Temperature Range	-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 898-1, DIN 934, IEC 60947-1

Parent Products

This component is used in the following industrial products

Motor Terminal Block

A motor terminal block is a standardized electrical component that provides secure, insulated connection points for motor winding leads.

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Terminal Blocks/Connectors

Electrical connection interface for temperature sensor wiring in industrial control modules

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Engineering Analysis

Risks & Mitigation

Over-tightening causing thread damage
Under-tightening leading to high resistance and overheating
Corrosion in humid environments
Vibration-induced loosening

FMEA Triads

Trigger: Incorrect torque application
Failure: Poor electrical contact or mechanical damage
Mitigation: Use calibrated torque tools and follow manufacturer specs

Trigger: Material corrosion
Failure: Increased resistance or connection failure
Mitigation: Select plated or stainless-steel screws for harsh environments

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Thread tolerance per ISO 965-1, dimensional accuracy within ±0.1mm

Test Method

Torque testing per ISO 898-1, electrical continuity testing, salt spray testing per ISO 9227 for corrosion resistance

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

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Manufacturers of Terminal Screw

Manufacturer profiles associated with Terminal Screw.

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Related Components

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.

Current Sense Resistor

A precision resistor used to measure current flow in electrical circuits by converting current to a measurable voltage drop.

Frequently Asked Questions

What is the recommended torque for a terminal screw?

Torque varies by size and material but typically ranges from 0.5 Nm for M3 screws to 2.5 Nm for M6 screws. Always follow manufacturer specifications to avoid overtightening or loose connections.

Can terminal screws be reused?

Limited reuse is possible if threads and clamping surfaces are undamaged, but replacement is recommended after multiple cycles to maintain reliability, especially in high-vibration environments.

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 Screw