SINOFUSE RSZ307-4-S5P Series 1000VDC High-Speed Fuse

The SINOFUSE RSZ307-4-S5P Series is a high-speed DC fuse family designed for high-current electrical protection applications. According to the current SINOFUSE manufacturer product information, the series is rated at DC 1000V and covers a current range from 1250A to 1600A.

The RSZ307-4-S5P Series uses the aR utilization category and has a manufacturer-listed breaking capacity of 50kA. It is relevant to electrical protection applications involving lithium battery cabinets, high-voltage DC systems (HVDC), charging infrastructure, and data center power equipment.

This technical guide explains the RSZ307-4-S5P electrical specifications, protection characteristics, application considerations, model identification, and important requirements for engineering selection and replacement.

RSZ307-4-S5P Series Technical Specifications

Manufacturer: SINOFUSE
Series: RSZ307-4-S5P
Product Type: High-speed DC fuse
Rated Voltage: DC 1000V
Manufacturer-Listed Current Range: 1250A to 1600A
Utilization Category: aR
Breaking Capacity: 50kA
Reference Standards: IEC 60269 and GB/T 13539
Application Areas: Lithium battery cabinets, HVDC systems, charging infrastructure, and data center electrical equipment

Technical Note: These specifications reflect the manufacturer's current published series information. Exact mechanical dimensions, installation requirements, electrical performance characteristics, and certification status should be verified for the selected part number using applicable manufacturer documentation.

Key Characteristics

High-speed DC fuses are used where protection against substantial short-circuit currents is required. Electrical performance must be evaluated according to the characteristics of the protected circuit.

The RSZ307-4-S5P Series provides the following manufacturer-listed characteristics:

DC 1000V rated voltage
High-current ratings within the published 1250A–1600A range
aR partial-range high-speed protection
50kA manufacturer-listed breaking capacity
Applications involving high-voltage DC distribution and power-electronic equipment

Understanding the aR Utilization Category

The SINOFUSE RSZ307-4-S5P Series uses the aR utilization category.

The aR category identifies a partial-range high-speed fuse intended to interrupt fault currents within its specified operating range.

This protection characteristic is relevant to power-electronic applications where high fault currents and current-limiting performance must be considered.

However, aR fuses should not automatically be treated as complete full-range overload protection devices.

Depending on the electrical installation, additional protective devices or appropriate protection coordination may be required to address overload currents and fault conditions outside the fuse's specified interruption range.

DC 1000V Rating and Breaking Capacity

The manufacturer specifies a rated voltage of DC 1000V and a breaking capacity of 50kA for the RSZ307-4-S5P Series.

Breaking capacity is an important parameter when selecting a fuse for high-current DC systems. It describes the fault-current interruption capability under the applicable manufacturer test conditions.

Engineers should verify that the selected fuse is suitable for the prospective short-circuit current of the installation.

For DC applications, additional factors may include the circuit time constant, operating voltage, fault-current characteristics, and the manufacturer's specified test conditions.

Engineering Note: An older 2020 design-verification document references a 50kA breaking capacity at a 10–15ms time constant. Because that document was issued for temporary design verification, those historical test conditions should not be assumed to represent the current finalized specification without manufacturer confirmation.

RSZ307-4-S5P Model Range

The current SINOFUSE product overview identifies a rated-current range from 1250A to 1600A.

Apexon Supply lists the RSZ307-4-S5P-1250A1000V model in its product catalog.

For other current ratings within the manufacturer-listed series range, the exact model designation, technical specifications, and availability should be confirmed before ordering.

RSZ307-4-S5P 1250A 1000V Model

The RSZ307-4-S5P-1250A1000V is a DC 1000V high-speed fuse model within the manufacturer's currently published series current range.

For product information and purchasing inquiries, visit:

SINOFUSE RSZ307-4-S5P 1250A 1000V High-Speed Fuse

Manufacturer Specification Revision Note

An earlier RSZ307-4-S5P design-verification specification, revised in June 2020, identified a broader preliminary current range from 800A to 1800A.

That document explicitly stated that it was a temporary design-verification specification with a validity period of three months and that the formal technical parameters could be revised.

The manufacturer's current public series overview identifies a narrower 1250A–1600A current range.

Therefore, models or installation parameters appearing only in the older preliminary specification should be verified with SINOFUSE before being used for current engineering selection.

Typical RSZ307-4-S5P Applications

High-Voltage DC Distribution Systems

High-voltage DC distribution equipment requires protective devices selected according to the system's operating voltage, continuous current, prospective short-circuit current, and protection coordination requirements.

SINOFUSE identifies HVDC applications among the relevant operating scenarios for the RSZ307-4-S5P Series.

Lithium Battery Cabinets

Lithium battery cabinets can involve substantial DC operating and fault currents, particularly in high-capacity electrical installations.

Fuse selection should account for the battery system voltage, current levels, prospective fault current, and coordination with other protection devices.

Engineers should verify that the selected RSZ307-4-S5P model meets the electrical and mechanical requirements of the specific installation.

Charging Infrastructure

High-power DC charging infrastructure requires appropriate electrical protection for its distribution and conversion circuits.

SINOFUSE identifies charging infrastructure as an application area for the RSZ307-4-S5P Series.

Selection should consider circuit voltage, continuous load current, prospective fault current, operating temperature, and equipment protection requirements.

Data Center Power Equipment

High-current electrical distribution and power conversion equipment used in data center infrastructure may require fast-acting protection against electrical faults.

The RSZ307-4-S5P Series is included in the manufacturer's data center application portfolio.

Suitability should be verified according to the specific DC system configuration and equipment requirements.

I²t Characteristics and Protection Coordination

When selecting a high-speed fuse for electrical protection applications, engineers may need to evaluate the fuse's pre-arcing I²t and total clearing I²t characteristics.

Pre-Arcing I²t: The current-squared integral accumulated before the fuse element melts.

Total Clearing I²t: The current-squared integral accumulated throughout the complete interruption process.

These characteristics can be important when coordinating fuse protection with power-electronic devices, conductors, and other electrical components.

Model-specific I²t values should be obtained from the applicable current manufacturer specification. Values from preliminary or superseded documents should not be substituted without verification.

Mechanical Dimensions and Mounting Requirements

Mechanical compatibility is an important part of fuse selection, especially for replacement applications in high-current DC equipment.

Engineers should verify the following installation parameters:

Overall fuse dimensions
Terminal configuration and contact dimensions
Mounting-hole and threaded connection requirements
Required installation hardware
Manufacturer-recommended tightening torque
Electrical clearances and insulation requirements
Contact resistance and thermal operating conditions

The manufacturer's preliminary 2020 design-verification document includes an M12 mounting arrangement and a recommended torque value. These historical installation details should be confirmed against a current approved dimensional drawing before installation.

Operating Conditions and Thermal Considerations

The operating environment can affect fuse selection and performance.

High-current DC fuse installations should be evaluated with consideration of:

Continuous operating current
Ambient temperature
Enclosure temperature and ventilation
Terminal connection resistance
Heat generated by nearby components
Installation altitude
Applicable current-derating requirements

The manufacturer's current operating-temperature limits and applicable correction factors should be verified using the latest model-specific technical documentation.

RSZ307-4-S5P Selection Checklist

Before selecting an RSZ307-4-S5P fuse, engineers and industrial procurement professionals should verify:

Exact Model: Confirm the manufacturer part number.
Rated Voltage: Verify the DC operating voltage.
Rated Current: Select the appropriate model for the intended load.
Breaking Capacity: Evaluate the prospective short-circuit current and applicable test conditions.
Protection Category: Confirm aR fuse coordination requirements.
I²t Characteristics: Review applicable manufacturer performance data.
Mounting Requirements: Verify dimensions, terminals, hardware, and torque.
Thermal Conditions: Consider ambient temperature, enclosure conditions, and current correction.
Certification Requirements: Verify applicable approvals for the exact part number.
Replacement Suitability: Confirm both electrical and mechanical compatibility.

Browse SINOFUSE RSZ307-4-S5P Fuses

Apexon Supply provides a dedicated product collection for the SINOFUSE RSZ307-4-S5P Series.

Explore the collection for listed models, product information, and sourcing inquiries:

Browse SINOFUSE RSZ307-4-S5P 1000VDC High-Speed Fuse Collection

Related SINOFUSE Technical Resources

Explore additional SINOFUSE fuse series and technical information:

Series Selection Note: RSZ307-4-S5P, RSZ307-5-W7P, and RSZ307-5-DAV are separate fuse families. Similar current ratings or voltage levels do not establish electrical or mechanical interchangeability.

Industrial Sourcing and Technical Support

Apexon Supply supports industrial buyers with SINOFUSE product identification, specification review, model selection, technical cross-reference, and international sourcing coordination.

For RSZ307-4-S5P product availability, technical information, or quotation requests, please provide the exact model number, required current rating, quantity, and available equipment or application information.

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