5STP 1 Glass Cartridge Fuse - Equivalent & Substitute Parts

Part Overview

The 5STP 1 is a 1 A, 250 V AC/DC glass cartridge fuse with slow-blow response characteristics, designed for through-hole mounting in 5mm x 20mm form factor applications. Manufactured by Bel Fuse Inc., this part carries an Obsolete product status. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain resilience, and support legacy system maintenance where this component remains in active use.

Key Parameters

Parameter	Value
Current Rating	1 A
Voltage Rating (AC)	250 V
Fuse Type	Cartridge, Glass
Response Time	Slow Blow
Package / Case	5mm x 20mm (Axial)
Mounting Type	Through Hole
Operating Temperature Range	-55°C ~ 125°C
Breaking Capacity @ Rated Voltage	35 A

Substitute Part Grouping Explanation

Substitute parts for the 5STP 1 are grouped into two categories based on electrical and mechanical compatibility:

Direct Manufacturer Substitutes maintain identical electrical characteristics and mechanical form factor, enabling drop-in replacement without circuit redesign:

5STP 1-R (Bel Fuse Inc., Active status)
0034.3117.PT (SCHURTER Inc., Active status)
0217001.MXEP (Littelfuse Inc., Active status)

Parametric Equivalents share the same current rating (1 A), voltage rating (250 V), fuse type (cartridge glass), response time (slow blow), package dimensions (5mm x 20mm), and operating temperature range (-55°C ~ 125°C), but may differ in breaking capacity, melting I²t, or DC cold resistance:

5ETP 1-R (Bel Fuse Inc., Active status)
5TTP 1-R (Bel Fuse Inc., Active status)
TSC-P-1A (OptiFuse, Active status)

Substitution eligibility is determined by matching: current rating, voltage rating, fuse type, response time, package dimensions, and mounting type. Variations in breaking capacity and melting I²t do not preclude substitution when the primary electrical and mechanical parameters align.

Parameter Comparison

Part Number	Manufacturer	Current Rating (A)	Voltage Rating (V AC)	Response Time	Breaking Capacity (A)	Melting I²t	DC Cold Resistance (Ohms)	Product Status	RoHS Status
5STP 1	Bel Fuse Inc.	1	250	Slow Blow	35	2.4	0.07	Obsolete	Non-compliant
5STP 1-R	Bel Fuse Inc.	1	250	Slow Blow	35	2.4	0.095	Active	ROHS3 Compliant
5ETP 1-R	Bel Fuse Inc.	1	250	Slow Blow	150	28	0.11	Active	ROHS3 Compliant
5TTP 1-R	Bel Fuse Inc.	1	250	Slow Blow	100	8.63	0.27	Active	ROHS3 Compliant
0034.3117.PT	SCHURTER Inc.	1	250	Slow Blow	35	3.3	—	Active	ROHS3 Compliant
0217001.MXEP	Littelfuse Inc.	1	250	Fast Blow	35	1.045	0.0964	Active	ROHS3 Compliant
TSC-P-1A	OptiFuse	1	250	Slow Blow	100	2.242	—	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: 5STP 1-R

The 5STP 1-R is the direct active-status replacement from the original manufacturer, Bel Fuse Inc. It maintains identical electrical specifications (1 A, 250 V, slow-blow response, 35 A breaking capacity) and mechanical form factor. The part is ROHS3 compliant and carries expanded approval certifications (CCC, CE, CSA, cURus, IMQ, SEMKO, VDE) compared to the obsolete 5STP 1. Current inventory is 1780 units.

Secondary Recommendations: 5ETP 1-R and 5TTP 1-R

Both parts are active Bel Fuse Inc. products with identical current, voltage, and response characteristics. They differ in breaking capacity (150 A and 100 A respectively) and melting I²t values. These parts are suitable where higher breaking capacity is acceptable or required by circuit design. Both are ROHS3 compliant with strong approval agency coverage.

Cross-Manufacturer Alternative: 0034.3117.PT (SCHURTER Inc.)

This part matches the 5STP 1 in all critical electrical parameters and maintains the same 35 A breaking capacity. Physical dimensions vary slightly (5.40mm x 22.50mm versus 5.50mm x 21.00mm), requiring mechanical verification for board layout compatibility. ROHS3 compliant with cURus certification.

Note on 0217001.MXEP (Littelfuse Inc.)

This part differs in response time classification (Fast Blow versus Slow Blow). While mechanically and electrically compatible in current and voltage ratings, the faster response characteristic may alter circuit protection behavior. Use only where fast-blow response is acceptable or required.

Frequently Asked Questions (FAQ)

Q: Can I use 5ETP 1-R or 5TTP 1-R as direct replacements for 5STP 1?

A: Yes. Both parts share the same current rating (1 A), voltage rating (250 V), fuse type (cartridge glass), response time (slow blow), package dimensions (5mm x 20mm), and operating temperature range. The higher breaking capacities (150 A and 100 A) do not prevent substitution; they indicate enhanced fault-current handling capability. Verify that your circuit design does not depend on the specific 35 A breaking capacity of the original part.

Q: What is the difference between slow-blow and fast-blow response?

A: Response time determines how quickly the fuse element melts under overcurrent conditions. Slow-blow fuses tolerate temporary inrush currents and are used in circuits with inductive loads or startup transients. Fast-blow fuses respond immediately to overcurrent and are used in circuits requiring rapid protection. The 0217001.MXEP is fast-blow; all other substitutes are slow-blow. Substitution between response types requires circuit analysis.

Q: Are there mechanical compatibility concerns with SCHURTER 0034.3117.PT?

A: The SCHURTER part has slightly different dimensions (5.40mm x 22.50mm versus 5.50mm x 21.00mm). Verify that your fuse holder accommodates these tolerances. The difference is minor but may affect fit in tightly constrained board layouts.

Q: Why is the original 5STP 1 marked Obsolete?

A: The 5STP 1-R is the active replacement from Bel Fuse Inc. and is recommended for new designs and ongoing production. The original 5STP 1 remains available in inventory (935 units) for legacy system support but is no longer actively manufactured or promoted.

Q: Which substitute offers the best RoHS compliance and certification coverage?

A: All active substitutes are ROHS3 compliant. The 5STP 1-R offers the broadest approval agency coverage (CCC, CE, CSA, cURus, IMQ, SEMKO, VDE) and is the direct manufacturer replacement. The 0217001.MXEP (Littelfuse) also provides extensive certifications (BSI, CE, CCC, CSA, KC, PSE, SEMKO, UR, VDE) but differs in response time.

Q: Can I mix different substitute parts in the same circuit board?

A: All substitutes are electrically and mechanically compatible for the same circuit application. However, using different manufacturers or response times in parallel protection circuits may introduce inconsistent fault-current handling. Maintain consistency within a single design unless circuit analysis explicitly permits variation.

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