FT600-1250-2 Equivalent & Substitute Parts

Part Overview

The FT600-1250-2 is a 1.25A 600VAC board mount surface mount fuse manufactured by Littelfuse Inc. as part of the FT600 and Raychem series. This component is classified as obsolete, making identification of suitable substitute parts essential for ongoing system maintenance and new design implementations. The fuse is designed for telecom applications with fast blow response characteristics and operates across a temperature range of -55°C to 125°C.

Substiute Parts

FT600-1250-2

Littelfuse Inc.In Stock: 5414FT600-1250-2 Datasheet

Current PartRFQ

04611.25ER

Littelfuse Inc.In Stock: 23980204611.25ER Datasheet

DirectRFQ

TR2/TCP1.25-R

Eaton - Electronics DivisionIn Stock: 3891TR2/TCP1.25-R Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FT600-1250-2 are qualified based on the following critical parameters:

Primary Matching Criteria:

• Current Rating: 1.25A (exact match required)
• Mounting Type: Surface Mount (exact match required)
• Fuse Type: Board Mount (exact match required)
• Package / Case: 2-SMD, Square End Block (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)

Secondary Compatibility Parameters:

• Voltage Rating - AC: 600 VAC minimum (equal or higher acceptable)
• Breaking Capacity: 60A minimum at rated voltage
• RoHS Compliance: ROHS3 or equivalent
• Approval Agencies: CSA and/or UL certification

The two identified substitute parts meet these criteria with the following distinctions:

04611.25ER (Littelfuse Inc., Telelink® 461 series): Active product status with dual voltage capability (600 VAC / 80 VDC), slow blow response, and higher inventory availability.

TR2/TCP1.25-R (Eaton - Electronics Division, TCP series): Active product status with reduced voltage rating (250 VAC) and different response time specification, representing a lower-voltage alternative.

Parameter Comparison

Engineering Selection Recommendations

04611.25ER is the primary substitute for FT600-1250-2 applications. Both components are manufactured by Littelfuse Inc., share identical current ratings, voltage ratings, mounting specifications, and operating temperature ranges. The 04611.25ER maintains ROHS3 compliance and CSA/UR certifications. The primary operational difference is response time classification (slow blow versus fast blow), which must be evaluated against circuit protection requirements. The 04611.25ER is an active product with significantly higher inventory availability (239,708 units in stock).

TR2/TCP1.25-R is a secondary alternative suitable only for applications where the AC voltage requirement does not exceed 250 VAC. This Eaton component meets the current rating, mounting type, and package specifications but operates at a reduced voltage rating. The breaking capacity at rated voltage (50A) is marginally lower than the original specification. This option is appropriate for lower-voltage telecom circuit protection scenarios.

For direct replacement in 600 VAC applications, 04611.25ER is the recommended substitute. For applications operating at 250 VAC or lower, TR2/TCP1.25-R provides an alternative from an established manufacturer with active product status.

Frequently Asked Questions (FAQ)

Q: Can 04611.25ER directly replace FT600-1250-2 in all applications?

A: 04611.25ER matches all critical parameters (current rating, voltage rating, mounting type, package, operating temperature) required for substitution. The response time difference (slow blow versus fast blow) must be verified against circuit protection requirements. Both components are rated for 600 VAC and 1.25A with identical package specifications.

Q: What is the key difference between 04611.25ER and FT600-1250-2?

A: The primary difference is response time classification. FT600-1250-2 is fast blow; 04611.25ER is slow blow. Additionally, 04611.25ER includes DC voltage rating capability (80 VDC), which the original part does not specify. Both maintain identical AC voltage ratings, current ratings, and operating temperature ranges.

Q: Is TR2/TCP1.25-R suitable for 600 VAC applications?

A: No. TR2/TCP1.25-R is rated for 250 VAC maximum. This component is suitable only for applications where the AC voltage requirement does not exceed 250 VAC. For 600 VAC applications, 04611.25ER is the appropriate substitute.

Q: Are all substitute parts RoHS compliant?

A: Yes. FT600-1250-2 is ROHS3 compliant, 04611.25ER is ROHS3 compliant, and TR2/TCP1.25-R is RoHS compliant. All three components meet current environmental compliance standards.

Q: What certifications do the substitute parts carry?

A: 04611.25ER carries CSA and UR certifications. TR2/TCP1.25-R carries CSA and UR certifications. The original FT600-1250-2 carries CSA and UL certifications. Both substitutes maintain recognized safety agency approvals suitable for telecom applications.

Q: Are the physical dimensions compatible between FT600-1250-2 and its substitutes?

A: All three components use 2-SMD, Square End Block packaging. Dimensional variations are minimal: FT600-1250-2 measures 10.20mm x 3.10mm x 3.10mm; 04611.25ER measures 10.10mm x 3.12mm x 3.12mm; TR2/TCP1.25-R measures 10.29mm x 2.77mm x 2.77mm. These variations are within standard PCB footprint tolerances for surface mount applications.