GSAP 1.25-R Equivalent & Substitute Parts

Part Overview

The GSAP 1.25-R is a 1.25 A ceramic cartridge fuse rated for 250 V AC operation, manufactured by Bel Fuse Inc. This component is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system maintenance and component procurement. The fuse is designed for through-hole mounting in 3AB, 3AG form factor applications requiring slow-blow response characteristics.

Substiute Parts

GSAP 1.25-R

Bel Fuse Inc.In Stock: 789GSAP 1.25-R Datasheet

Current PartRFQ

03251.25MXP

Littelfuse Inc.In Stock: 105103251.25MXP Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the GSAP 1.25-R is determined by strict equivalence across the following electrical and mechanical parameters:

• Current Rating: 1.25 A (exact match required)
• Voltage Rating - AC: 250 V (exact match required)
• Fuse Type: Cartridge, Ceramic (exact match required)
• Response Time: Slow Blow (exact match required)
• Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (Axial) (exact match required)
• Mounting Type: Through Hole (exact match required)
• Operating Temperature Range: -55°C ~ 125°C (exact match required)

The substitute part 03251.25MXP from Littelfuse Inc. meets all mandatory electrical and mechanical criteria for direct substitution. This part maintains identical current and AC voltage ratings, ceramic cartridge construction, slow-blow response, and physical form factor specifications.

Parameter Comparison

Engineering Selection Recommendations

The 03251.25MXP from Littelfuse Inc. is the qualified substitute for the obsolete GSAP 1.25-R. Selection is based on the following engineering criteria:

• Electrical equivalence: Identical current rating (1.25 A) and AC voltage rating (250 V)
• Mechanical compatibility: Matching 3AB, 3AG form factor and through-hole mounting configuration
• Thermal performance: Identical operating temperature range (-55°C ~ 125°C)
• Regulatory compliance: Both parts hold CE, CSA, and PSE certifications; the substitute additionally carries UL approval
• Product availability: The substitute is in active production status with confirmed inventory, whereas the original part is obsolete
• RoHS compliance: Both parts meet ROHS3 requirements

The substitute part's additional DC voltage rating (125 V) and enhanced DC breaking capacity (10 kA) provide expanded application flexibility without compromising AC circuit performance.

Frequently Asked Questions (FAQ)

Q: Can the 03251.25MXP be used as a direct replacement for the GSAP 1.25-R?

A: Yes. Both parts share identical current rating (1.25 A), AC voltage rating (250 V), ceramic cartridge construction, slow-blow response, and 3AB, 3AG physical form factor. Mechanical and electrical compatibility is confirmed.

Q: What is the significance of the DC voltage rating difference?

A: The GSAP 1.25-R does not specify a DC voltage rating, while the 03251.25MXP is rated for 125 V DC. This additional specification in the substitute part does not affect AC-only applications and provides expanded capability for dual-voltage circuits.

Q: How do the melting I²t values compare?

A: The GSAP 1.25-R has a melting I²t of 25, while the 03251.25MXP has a melting I²t of 24. This minor difference (4%) falls within acceptable tolerance for slow-blow ceramic fuse characteristics and does not impact substitution validity.

Q: Are there differences in DC cold resistance?

A: The GSAP 1.25-R has a DC cold resistance of 0.248 Ohms, while the 03251.25MXP measures 0.268 Ohms. This 8% difference is within normal manufacturing tolerance for ceramic cartridge fuses and does not affect circuit performance in standard applications.

Q: What certifications apply to both parts?

A: Both the GSAP 1.25-R and 03251.25MXP hold CE, CSA, and PSE certifications. The substitute additionally carries UL approval, providing broader regulatory acceptance in North American markets.

Q: Why is the original part listed as obsolete?

A: The GSAP 1.25-R is classified as obsolete by the manufacturer, indicating discontinued production. The 03251.25MXP remains in active production, ensuring long-term availability and supply chain continuity.