Fusible Core: Voltage Rating Up to 600V AC/DC

Q: What is the primary function of a fusible core?

The primary function is to provide fail-safe thermal protection by melting at a predetermined temperature to interrupt electrical circuits, preventing equipment damage or fire due to overheating.

Q: How do you select the correct melting temperature for a fusible core?

Select based on the maximum safe operating temperature of the protected equipment, typically 10-20°C above normal operating temperature but below the damage threshold of components.

Q: Can a fusible core be reset or reused after activation?

No, fusible cores are one-time-use devices. After melting, they must be replaced to restore protection, ensuring reliability and safety.

Q: What industries commonly use fusible cores?

Common in electrical equipment manufacturing, automotive systems, industrial machinery, HVAC systems, and consumer appliances where thermal management is critical.

Component Specifications

Definition

A fusible core is a precision-engineered thermal release element used in industrial machinery and electrical systems. It consists of a metal alloy core with a precisely calibrated melting point, housed within a protective casing. When ambient or operational temperatures exceed the predetermined threshold, the core melts, triggering a mechanical or electrical disconnection to halt equipment operation, thereby preventing thermal damage, fire hazards, or system failures. This component is critical in applications requiring fail-safe thermal protection.

Working Principle

The fusible core operates on the principle of phase change at a specific temperature. Under normal operating conditions, it remains solid and maintains circuit continuity. When temperature rises to its designed melting point (e.g., due to overload, short circuit, or environmental factors), the core material undergoes a solid-to-liquid phase transition. This melting action either breaks an electrical connection directly or activates a secondary mechanism (like a spring release) to open the circuit, interrupting power flow and stopping the machine to prevent overheating.

Materials

Typically made from eutectic alloys such as tin-lead (Sn-Pb), bismuth-based alloys (e.g., Bi-Pb-Sn-Cd), or lead-free alternatives like tin-silver-copper (Sn-Ag-Cu). The alloy composition is precisely formulated to achieve a specific melting temperature range (e.g., 70°C to 200°C). The casing is often ceramic, glass, or heat-resistant polymer to contain the molten material and provide electrical insulation.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Dimensions	Diameter: 5mm to 20mm, Length: 10mm to 50mm
Response Time	< 5 seconds at threshold temperature
Current Rating	1A to 30A
Voltage Rating	Up to 600V AC/DC
Housing Material	Ceramic or high-temperature polymer
Melting Temperature	70°C to 200°C (customizable)
Operating Temperature Range	-40°C to +85°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 8820, DIN 72581-3, IEC 60269

Parent Products

This component is used in the following industrial products

Thermal Release Element

A safety component within a spring actuator that disengages or releases the actuator mechanism when a predetermined temperature threshold is exceeded.

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Engineering Analysis

Risks & Mitigation

Incorrect melting temperature selection leading to premature failure or inadequate protection
Material degradation over time affecting response accuracy
Improper installation causing mechanical stress or poor thermal coupling
Environmental contaminants altering melting characteristics

FMEA Triads

Trigger: Alloy composition deviation during manufacturing
Failure: Melting point shifts, causing early or delayed activation
Mitigation: Implement strict quality control on raw materials and use calibrated testing (e.g., differential scanning calorimetry) for each batch.

Trigger: Thermal cycling or vibration in operation
Failure: Mechanical fatigue or cracking of the housing, compromising insulation
Mitigation: Design with robust, vibration-resistant casings and perform lifecycle testing under simulated operational conditions.

Trigger: Exposure to corrosive environments
Failure: Corrosion of alloy or housing, altering thermal properties or causing electrical leakage
Mitigation: Use corrosion-resistant materials (e.g., stainless steel casings, inert alloys) and apply protective coatings where applicable.

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Melting temperature tolerance typically ±5°C or ±3%, as per ISO 8820 standards for thermal protectors

Test Method

Testing involves controlled heating in an oven or bath with temperature monitoring per IEC 60269, measuring activation temperature and time, followed by electrical continuity checks.

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.

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Manufacturers of Fusible Core

Manufacturer profiles associated with Fusible Core.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the primary function of a fusible core?