LA70Q4504 Fuse Cartridge Equivalent & Substitute Parts

Part Overview

The LA70Q4504 is a 450A cartridge fuse rated for 700 VAC / 650 VDC operation, designed for bolt mount installation in industrial and electrical applications. This part is classified as obsolete, making identification of suitable substitutes necessary for ongoing system maintenance and component procurement.

The LA70Q4504 features a cylindrical design with blade terminal (bolt) mounting, a breaking capacity of 100 kA at rated voltage, and ROHS3 compliance. With 633 units currently in stock, this part remains available but requires alternative solutions for new designs or long-term supply assurance.

Substiute Parts

LA70Q4504

Littelfuse Inc.In Stock: 665LA70Q4504 Datasheet

Current PartRFQ

L70QS450.X

Littelfuse Inc.In Stock: 785L70QS450.X Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LA70Q4504 is determined by the following critical parameters:

• Current Rating: Must match 450A
• Voltage Rating - AC: Must match or exceed 700 VAC
• Voltage Rating - DC: Must match or exceed 650 VDC
• Fuse Type: Must be Cartridge
• Mounting Type: Must be Bolt Mount
• Package / Case: Must be Cylindrical with Blade Terminal (Bolt)

The L70QS450.X meets all substitution criteria. While dimensional differences exist between the main part and substitute, both maintain compatible bolt mount interfaces and cylindrical blade terminal configurations suitable for the same mounting infrastructure.

Parameter Comparison

Engineering Selection Recommendations

The L70QS450.X is the manufacturer-recommended substitute for the LA70Q4504. Selection of this substitute is supported by the following factors:

• Electrical Compatibility: The substitute maintains identical current rating (450A) and AC voltage rating (700 VAC), with DC voltage rating increased to 700 VDC, exceeding the original 650 VDC requirement.
• Product Status: The L70QS450.X is classified as Active, ensuring continued availability and supply chain stability compared to the obsolete LA70Q4504.
• Regulatory Compliance: Both parts maintain ROHS3 compliance. The L70QS450.X carries expanded approval certifications (CE, cURus, UR) compared to the LA70Q4504 (UR only).
• Mechanical Interface: Both parts utilize bolt mount installation with cylindrical blade terminal configuration, maintaining compatibility with existing mounting infrastructure.
• Dimensional Variance: Physical dimensions differ between the two parts. System integration must account for the substitute's smaller diameter (2.000" vs. 2.500") and greater length (7.090" vs. 2.843").

Frequently Asked Questions (FAQ)

Q: Can the L70QS450.X directly replace the LA70Q4504 in existing installations?

A: Electrical substitution is valid based on current rating, voltage ratings, and fuse type compatibility. However, dimensional differences require verification that mounting space and bolt terminal positioning accommodate the substitute's 2.000" diameter and 7.090" length specifications.

Q: What is the significance of the increased breaking capacity in the L70QS450.X?

A: The L70QS450.X provides 200 kA AC breaking capacity compared to the LA70Q4504's 100 kA. This represents enhanced fault current handling capability and does not restrict substitution in applications designed for the original 100 kA specification.

Q: Are there compliance differences between the two parts?

A: The LA70Q4504 carries UR approval. The L70QS450.X carries CE, cURus, and UR approvals, providing broader regulatory recognition. Both maintain ROHS3 compliance.

Q: What is the response time characteristic of the L70QS450.X?

A: The L70QS450.X is classified as Fast Blow, indicating rapid response to overcurrent conditions. The LA70Q4504 response time specification is not provided in available documentation.

Q: How do the operating temperature ranges compare?

A: The L70QS450.X specifies an operating temperature range of -55°C to 125°C. The LA70Q4504 operating temperature specification is not provided in available documentation.