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MERSEN FUSE 250V 5SF 4A 5.20 MI5SF25V4
Mersen S090521 MI5SF25V4 quick-acting 5 x 20 mm glass miniature fuse rated at 4 A and 250 V AC with a 40 A breaking capacity.
Why Choose the Mersen S090521 5 x 20 mm Quick-Acting Miniature Fuse?
The Mersen S090521 is a compact and dependable 5 x 20 mm quick-acting miniature fuse designed to provide rapid overcurrent protection for electrical distribution circuits and industrial equipment. Part of the established Mersen 5SF IEC miniature fuse series, it helps protect sensitive electrical components by interrupting excessive current quickly.
Its fast-acting characteristic makes the S090521 suitable for circuits where significant start-up surges are not expected and prompt fault clearance is required. By limiting the duration of overload and short-circuit currents, the fuse helps reduce the risk of damage to wiring, electronic components and connected equipment.
Rated at 4 A and 250 V AC, the Mersen S090521 features a glass body and standard cylindrical dimensions for straightforward installation in compatible 5 x 20 mm fuse clips and holders. It is well suited to industrial control panels, instrumentation, power supplies and OEM electrical assemblies.
Key Advantages
- Quick-acting characteristic provides rapid overcurrent protection.
- 4 A current rating for industrial and electrical circuits.
- 250 V AC rated voltage for IEC applications.
- Compact 5 x 20 mm cylindrical fuse format.
- Helps minimise damage caused by sustained overloads and short circuits.
- Manufactured by Mersen for consistent electrical protection performance.
Key Features
- Mersen 5SF IEC miniature fuse series.
- 4 A rated current.
- 250 V AC rated voltage.
- Fast-acting operating characteristic.
- 40 A AC breaking capacity.
- 45.76 A²s melting I²t.
- Glass body with nickel-plated brass contact caps.
- RoHS-compliant construction.
Rapid Protection for Electrical Equipment
Quick-acting miniature fuses are designed to disconnect a circuit rapidly when current exceeds the permitted level. Their prompt response helps restrict the amount of fault energy reaching connected wiring and components, making them suitable for equipment that does not normally produce high start-up currents.
The Mersen S090521 provides reliable protection for electrical distribution circuits and industrial equipment when installed in a compatible holder and correctly selected for the circuit. Its compact construction supports straightforward replacement and integration into space-conscious electrical assemblies.
Typical Applications
- Industrial control panels.
- Electrical distribution circuits.
- Electronic power supplies.
- Instrumentation and measurement equipment.
- Automation systems.
- Control and signalling circuits.
- OEM electrical equipment.
- Industrial electronic assemblies.
Technical Specifications
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| Current | 4 A | |
|---|---|---|
| Voltage | 250 V | |
| Device Type | Fuse link | |
| Fuse Type | Miniature | |
| Fuse Size | 5x20 mm | |
| Fuse Class | Fast acting | |
| Manufacturer | Mersen | |
| Series | 5SF IEC Miniature Fuses | |
| Model | S090521 | |
| Catalogue number | MI5SF25V4 | |
| Product type | Quick-acting miniature fuse | |
| Fuse size | 5 x 20 mm | |
| Rated current | 4 A | |
| Rated voltage | 250 V AC | |
| Operating characteristic | Fast acting | |
| Breaking capacity | 40 A AC | |
| Melting I²t | 45.76 A²s | |
| Power dissipation at rated current | 0.88 W | |
| Maximum voltage drop | 0.08 V | |
| Body material | Glass | |
| Contact cap material | Nickel-plated brass | |
| Extinguishing agent | None | |
| Product diameter | 5.1 mm | |
| Product length | 20 mm | |
| Mounting type | Clip mounting | |
| Applicable standard | IEC 60127-2 Sheet 2 | |
| Product weight | approx. 1.2 g | |
| RoHS compliant | Yes |
Frequently Asked Questions
What is the Mersen S090521 used for?
The Mersen S090521 provides quick-acting overcurrent and short-circuit protection for electrical distribution circuits, industrial equipment and electronic systems.
What is the current rating of this fuse?
The S090521 has a rated current of 4 A.
What voltage is the Mersen S090521 rated for?
This miniature fuse is rated for operation at up to 250 V AC.
Is the S090521 a fast-acting fuse?
Yes. It has a quick-acting characteristic designed to interrupt excessive current rapidly and protect connected equipment.
Which fuse holder is required?
The S090521 should be installed in a compatible fuse holder or clip designed for standard 5 x 20 mm cylindrical fuses.
Trusted by Electrical Professionals Worldwide
Mersen miniature fuses are widely used by panel builders, equipment manufacturers and maintenance engineers to provide dependable, standards-compliant circuit protection across industrial and commercial applications.
