SPIDER Automation | F20AL250V 20A Fast-Acting Glass Fuse | 5 × 20mm Overcurrent Protection
The SPIDER Automation F20AL250V 20A Fast-Acting Glass Cartridge Fuse is an overcurrent protection component designed to interrupt excessive current in compatible electrical and electronic circuits. It carries a nominal 20A current rating and a stated 250V voltage rating, with a fast-acting response characteristic for applications requiring prompt interruption during qualifying overcurrent and short-circuit conditions. Its cylindrical 5 × 20mm glass-tube construction supports installation in compatible cartridge fuse holders.
The fuse features a glass body with silver-plated end caps and a stated typical cold resistance of 0.013Ω. Its low-breaking-capacity classification is an important selection consideration: the fuse must only be used where the prospective fault current is within its rated interruption capability. Matching the fuse’s current rating, voltage rating, response characteristic, physical dimensions and breaking capacity to the protected circuit is essential for appropriate protection.
Product Overview & Protection Function
A cartridge fuse is a sacrificial protection device that interrupts an electrical circuit when excessive current causes its internal fuse element to operate. Once the element opens, the circuit path is interrupted, helping prevent continued fault-current flow through connected wiring and electronic components.
The F20AL250V is specified as a 20A fast-acting fuse. Its response characteristic is intended for applications where a time-delay fuse is not suitable. The 20A rating represents the nominal fuse current, not an unrestricted operating-current guarantee under every ambient temperature or installation condition.
Technical Features & Construction
- Glass-Tube Body: Provides a transparent cylindrical enclosure for the internal fuse element.
- Silver-Plated End Caps: Provides plated terminal surfaces for electrical contact with compatible fuse-holder terminals.
- Fast-Acting Fuse Element: Designed to respond to qualifying overcurrent conditions without the intentional time delay associated with slow-blow fuse types.
- 5 × 20mm Cartridge Format: Provides a compact cylindrical form factor for compatible fuse holders and equipment.
- 20A Nominal Current: Defines the fuse’s stated rated current for circuit-selection purposes.
- 250V Voltage Rating: Provides the stated voltage rating; the applicable AC or DC rating should be verified for the intended circuit.
- Low Breaking Capacity: Requires careful matching to the prospective fault current at the installation point.
- Typical Cold Resistance: The stated resistance is 0.013Ω under cold conditions and should not be treated as the fuse’s resistance during operation.
Electrical Selection & Fuse Compatibility
Selecting a replacement fuse requires more than matching its physical size or nominal current. The 20A current rating, 250V voltage rating, fast-acting characteristic and breaking capacity must all be compatible with the protected circuit. A fuse with the correct 5 × 20mm dimensions but a different response characteristic or inadequate breaking capacity may not provide the intended protection.
The low-breaking-capacity classification is particularly important in circuits where a high prospective short-circuit current may be available. The fuse should only be installed after confirming that its interruption capability is suitable for the actual circuit fault conditions. The supplied voltage specification does not explicitly distinguish AC from DC, so the appropriate rating for the intended supply type must be confirmed before use.
Applications
This 20A fast-acting glass cartridge fuse can be considered for compatible equipment and electrical assemblies requiring replaceable 5 × 20mm overcurrent protection, provided the circuit’s voltage and prospective fault-current conditions fall within the fuse’s verified ratings.
- Electronic Equipment Protection: Provide replaceable overcurrent protection in compatible electronic equipment.
- Power Supply Assemblies: Protect suitable power supply circuits where the current, voltage and breaking-capacity requirements match.
- Electrical Control Equipment: Use in compatible control assemblies designed for 5 × 20mm cartridge fuses.
- Electrical Instrumentation: Provide fuse protection in equipment with a matching fuse-holder configuration and electrical requirements.
- Repair and Maintenance: Replace an existing cartridge fuse when its original specifications and holder compatibility are confirmed.
- Low-Voltage Electronic Assemblies: Use in suitable circuits where the fuse’s verified voltage and fault-interruption ratings are appropriate.
- Power Distribution Subassemblies: Protect compatible circuit branches where the prospective fault current remains within the fuse’s breaking capacity.
- Industrial Electronic Equipment: Integrate into compatible equipment designed around the specified cartridge fuse format and ratings.
Package Includes
- 1 × F20AL250V 20A Fast-Acting Glass Cartridge Fuse (5 × 20mm)
Product Specifications
| Parameter | Specification |
|---|---|
| Product Type | Glass cartridge fuse |
| Fuse Marking / Model | F20AL250V |
| Current Rating | 20A |
| Voltage Rating | 250V (AC/DC designation not provided) |
| Blow Characteristic | Fast Acting |
| Breaking Capacity Classification | Low breaking capacity |
| Fuse Body Material | Glass |
| End Cap Finish | Silver-plated |
| Fuse Format | Cylindrical cartridge |
| Nominal Size | 5 × 20mm |
| Specified Length | 20.22mm |
| Body Diameter | 5mm |
| Typical Cold Resistance | 0.013Ω |
| Approximate Product Weight | 1g |
| Mounting Arrangement | Compatible 5 × 20mm fuse holder |
| Package Quantity | 1 fuse |
Installation & Operating Recommendations
- Verify the Voltage Rating: Confirm that the 250V rating is appropriate for the intended supply type. Do not assume that an unspecified 250V rating automatically applies to both AC and DC circuits.
- Check Prospective Fault Current: Because this is a low-breaking-capacity fuse, verify that the available short-circuit current at the installation point is within its rated interruption capability.
- Match the Original Fuse: Confirm the 20A rating, fast-acting response, voltage rating, breaking capacity and 5 × 20mm dimensions before replacement.
- Use a Compatible Fuse Holder: Ensure that the holder is designed for the 5 × 20mm cartridge format and is suitably rated for the circuit.
- Account for Startup Current: Check normal operating and inrush-current behaviour to avoid unwanted fuse operation.
- Disconnect Power Before Replacement: Isolate the equipment and verify that it is de-energised before removing or installing the fuse.
- Investigate Repeated Fuse Failure: Identify the underlying overload or short circuit before fitting another fuse.
- Never Bypass the Fuse: Do not bridge the fuse holder or substitute a higher-current fuse to prevent repeated interruptions.
