Definition: A fully sealed structure where the fuse element (melt) is enclosed within a non-conductive housing, typically made of ceramic, glass, or reinforced plastic. The housing may be filled with arc-quenching materials (e.g., quartz sand, nitrogen) or hermetically sealed.

Key Features:

No exposed live parts; fully isolated from the external environment.

Modular design with standardized terminals (e.g., blade-type, bolted connections) for easy installation.

Examples: Cartridge fuses (e.g., ANSI/JIC types), high-voltage enclosed fuses (e.g., RN series), and EV fuses.

Definition: A non-sealed structure where the fuse element is exposed or partially enclosed, with minimal or no protective housing. The element is often visible and directly exposed to the surrounding air.

Key Features:

Simple design with basic support structures (e.g., clip-mounted wire fuses).

No arc-quenching materials; relies on air for heat dissipation and arc suppression.

Examples: Glass tube fuses (common in low-voltage circuits), open-wire fuses in old-fashioned panel boards, and some low-power electronic fuses.

Arc Management:

The sealed housing contains arc energy and prevents sparking to the external environment.

Quenching materials (e.g., quartz sand) rapidly cool and extinguish arcs, reducing the risk of phase-to-phase short circuits or explosions.

Safety Benefits:

Ideal for high-energy circuits (e.g., high voltage, high current) where arc flash hazards are significant.

Complies with strict safety standards (e.g., UL 248, IEC 60269) for industrial and hazardous environments.

Arc Management:

Arcs are released into the air, potentially causing flame ejection, metal vaporization, or surrounding material ignition.

Limited arc suppression capability; prone to prolonged arcing in high-current faults.

Safety Risks:

Unsuitable for circuits with high short-circuit currents or flammable environments (e.g., explosive atmospheres, fuel systems).

High risk of operator injury from arc flash during failure.

Sealed Against External Factors:

Resistant to moisture, dust, corrosive gases, and mechanical impacts.

Suitable for harsh environments such as outdoor power grids, industrial plants, and mobile vehicles.

Longevity:

Protected melt reduces oxidation and contamination, extending service life.

Vulnerable to Environment:

Exposed elements are prone to corrosion (e.g., rust from moisture), mechanical damage (e.g., vibration), or contamination (e.g., dust accumulation).

Limited lifespan in outdoor or high-humidity settings.

Application Restrictions:

Primarily used in controlled environments (e.g., indoor low-voltage circuits, electronics) with minimal environmental stress.

High-Capacity Performance:

Capable of handling high voltages (up to 110kV in power systems) and large currents (up to thousands of amperes).

Designed for industrial, utility, and transportation applications (e.g., data centers, EVs, substations).

Key Specifications:

High breaking capacity (e.g., 100kA or more) to interrupt severe faults.

Low-to-Medium Capacity:

Typically rated for low voltages (≤600V AC/DC) and small currents (≤100A).

Suitable for low-power applications like household appliances, small electronics, and lighting circuits.

Limitations:

Inadequate for high-energy faults; may fail catastrophically under overload.

Standardized Replacement:

Modular designs allow quick replacement without special tools (e.g., pull-out cartridges).

Some types include visual indicators (e.g., colored flags) to signal burnout.

Safety During Maintenance:

No exposed live parts during replacement, reducing 触电 risks (when properly de-energized).

Manual Handling Risks:

Exposed elements require direct contact during replacement, increasing the chance of electric shock or physical injury.

No standardized terminals; may require soldering or rewiring (e.g., in glass tube fuses).

Inconvenience:

Often requires circuit disassembly for inspection, leading to longer downtime.

Higher Cost:

Complex manufacturing (e.g., hermetic sealing, arc-quenching materials) increases production costs.

Premium for safety features and environmental durability.

Long-Term Value:

Reduces maintenance costs and downtime in critical systems.

Lower Cost:

Simple design and minimal materials make them inexpensive (e.g., glass fuses cost pennies each).

Trade-offs:

Higher risk of system damage or safety incidents in demanding applications.

Enclosed fuses are preferred for high-risk, high-energy applications where arc suppression, environmental protection, and reliability are non-negotiable.

Open fuses suit low-cost, low-power scenarios with minimal safety or environmental demands.