1. Introduction
This manual provides essential information for the safe and effective use of the Littelfuse Bussmann SC-30 Fuse. It covers product overview, safety guidelines, installation, and specifications. Please read this manual thoroughly before handling or installing the fuse.
2. Safety Information
WARNING: Electrical shock hazard. Always disconnect power before installing or replacing fuses. Installation should only be performed by qualified personnel.
- Ensure the power supply is completely disconnected and locked out before any work involving fuses.
- Never touch electrical components with wet hands or while standing on wet surfaces.
- Always use fuses with the correct voltage and amperage ratings for the circuit they are protecting. Using an incorrect fuse can lead to equipment damage, fire, or personal injury.
- Do not bypass or tamper with fuses.
- Wear appropriate personal protective equipment (PPE), such as insulated gloves and safety glasses, when working with electrical systems.
3. Product Overview
The Littelfuse Bussmann SC-30 is a Class G, time-delay cartridge fuse designed for general purpose basic protection against overcurrents. It is rated for 30 Amperes and suitable for both AC (480V) and DC (300V) applications. The time-delay characteristic allows for temporary overcurrents, such as motor starting surges, without blowing, while still providing protection against sustained overloads and short circuits.
Figure 3.1: Front view of the Bussmann SC-30 fuse, showing the green label with "BUSS Class G Fuse Type Ampere SC-30 Time-Delay" markings.
Figure 3.2: Side view of the Bussmann SC-30 fuse, displaying detailed specifications including "General Purpose Basic Protection Time-Delay Class G Fuse SC-30 480Vac AC IR 100kA 300Vdc DC IR 10kA".
4. Installation
Follow these steps for proper installation of the SC-30 fuse:
- Verify Compatibility: Ensure the SC-30 fuse matches the required amperage and voltage ratings for your specific electrical circuit and equipment. Refer to your equipment's documentation.
- Disconnect Power: Absolutely ensure all power to the circuit where the fuse will be installed is turned off and locked out. Use a voltage tester to confirm the circuit is de-energized.
- Remove Old Fuse (if applicable): Carefully remove the existing fuse from its holder. Note its orientation if it's a specific type.
- Insert New Fuse: Insert the Bussmann SC-30 fuse into the fuse holder. Ensure it is seated firmly and correctly. Do not force the fuse.
- Restore Power: Once the fuse is securely in place and all safety checks are complete, restore power to the circuit.
- Test Functionality: Verify that the protected equipment operates as expected.
Note: Fuses are designed for one-time use. A blown fuse must be replaced with a new one of the identical type and rating.
5. Operating Principle
The Bussmann SC-30 fuse functions as a sacrificial device designed to protect electrical circuits from overcurrent conditions. When the current flowing through the circuit exceeds the fuse's 30 Ampere rating for a sustained period (due to an overload) or instantaneously (due to a short circuit), the metallic element inside the fuse melts, creating an open circuit. This action interrupts the flow of electricity, preventing damage to wiring, equipment, and reducing the risk of fire.
As a time-delay fuse, the SC-30 is engineered to withstand temporary current surges that are common during the startup of motors or other inductive loads. This prevents nuisance blowing while still providing reliable protection against harmful overcurrents.
6. Maintenance
Fuses are generally maintenance-free components. However, periodic visual inspection of the fuse and its holder is recommended, especially in environments prone to vibration, dust, or extreme temperatures. Look for any signs of physical damage, discoloration, or loose connections. If any issues are observed, disconnect power and address them immediately.
7. Troubleshooting
If a circuit protected by an SC-30 fuse stops functioning, the fuse may have blown. Follow these troubleshooting steps:
- Identify Blown Fuse: Disconnect all power to the circuit. Visually inspect the fuse for a broken filament or discoloration, which indicates it has blown. Some fuse holders may have an indicator.
- Determine Cause: A blown fuse indicates an overcurrent condition. Investigate the circuit for potential causes such as:
- Overloaded circuit (too many devices drawing power).
- Short circuit in wiring or equipment.
- Faulty equipment connected to the circuit.
- Replace Fuse: Once the cause of the overcurrent is identified and rectified, replace the blown fuse with a new Littelfuse Bussmann SC-30 fuse. Never replace it with a fuse of a different rating.
- Repeated Blowing: If the fuse blows repeatedly after replacement, it indicates a persistent problem in the circuit or equipment. Consult a qualified electrician to diagnose and repair the issue.
8. Specifications
| Specification | Value |
|---|---|
| Brand | Littelfuse (Bussmann) |
| Model Number | SC-30 |
| Amperage Rating | 30 Amps |
| AC Voltage Rating | 480 Vac |
| DC Voltage Rating | 300 Vdc |
| Interrupting Rating (AC) | 100 kA |
| Interrupting Rating (DC) | 10 kA |
| Fuse Type | Class G, Time-Delay |
| Material | Copper |
| Mounting Type | Surface Mount (Cartridge) |
| Item Weight | 0.317 ounces |
| Package Dimensions | 2.56 x 1.1 x 0.43 inches |
9. Warranty and Support
For warranty information and technical support regarding your Littelfuse Bussmann SC-30 fuse, please refer to the official Littelfuse website or contact their customer service directly. Keep your purchase receipt for any warranty claims.
Littelfuse Official Website: www.littelfuse.com
