Introduction
This manual provides essential information for the safe and effective use of the Cooper FNA-1/2 Bussmann Fusetron Dual-Element Fuse. This fuse is designed to protect electrical circuits from overcurrent conditions, preventing damage to equipment and reducing fire hazards. It is a dual-element, time-delay fuse suitable for applications up to 250V AC.
Safety Information
Always prioritize safety when working with electrical components. Failure to follow these instructions may result in electric shock, fire, or serious injury.
- Disconnect Power: Always ensure power is disconnected at the main circuit breaker or fuse box before installing, inspecting, or replacing fuses.
- Qualified Personnel: Installation and maintenance should only be performed by qualified electricians or individuals with proper electrical knowledge.
- Correct Rating: Use only fuses with the correct voltage and current ratings for the circuit they are protecting. Using an incorrect fuse can lead to circuit damage or fire.
- Inspect Fuse Holder: Before inserting a new fuse, inspect the fuse holder for any signs of damage, corrosion, or loose connections.
- Do Not Bypass: Never bypass or tamper with a fuse. Fuses are critical safety devices.
- Personal Protective Equipment (PPE): Wear appropriate PPE, such as insulated gloves and safety glasses, when working with electrical systems.
Product Overview
Figure 1: Front view of the Cooper FNA-1/2 Bussmann Fusetron Dual-Element Fuse. This image shows the cylindrical body of the fuse with "FUSETROn DUAL-ELEMENT FUSE FNA-1/2" printed on its label.
Figure 2: Close-up view of the label on the Cooper FNA-1/2 Bussmann Fusetron Dual-Element Fuse. The label clearly displays "FUSETROn DUAL-ELEMENT FUSE" and "FNA-1/2", indicating its type and model number.
The Cooper FNA-1/2 is a plug fuse, specifically a dual-element, time-delay type. This design allows it to handle temporary overloads, such as motor starting currents, without blowing, while still providing rapid protection against short circuits and sustained overloads. It is commonly used in residential and light commercial applications for protecting motor circuits and other inductive loads.
Setup and Installation
Follow these steps for proper installation of the FNA-1/2 fuse:
- Verify Power Disconnection: Confirm that the power to the circuit where the fuse will be installed is completely off. Use a voltage tester to ensure no live current is present.
- Identify Fuse Holder: Locate the fuse holder in your electrical panel or equipment.
- Remove Old Fuse (if applicable): If replacing an old fuse, carefully remove it. Note its rating for comparison.
- Inspect New Fuse: Visually inspect the new Cooper FNA-1/2 fuse for any physical damage.
- Insert Fuse: Gently insert the new fuse into the fuse holder. Ensure it is seated firmly and correctly. Do not force it.
- Restore Power: Once the fuse is securely in place, restore power to the circuit.
- Test Circuit: Verify that the circuit is functioning as expected.
Important: Always match the fuse's voltage and amperage rating to the circuit's requirements. The FNA-1/2 is rated for 250V AC and 0.5 Amps (1/2 Amp).
Operating Principles
The Cooper FNA-1/2 is a passive protective device. It operates by interrupting the flow of current when an overcurrent condition occurs. Its dual-element, time-delay characteristic means:
- Short Circuit Protection: In the event of a severe short circuit, the fuse will blow almost instantaneously to prevent damage.
- Overload Protection (Time-Delay): For moderate, sustained overloads (e.g., a motor starting up), the fuse allows a brief period of higher current before blowing. This prevents nuisance tripping while still protecting the circuit from prolonged excessive current.
When the fuse blows, it creates an open circuit, stopping the flow of electricity and protecting downstream components from damage.
Maintenance
Fuses are generally maintenance-free components. However, periodic inspection is recommended:
- Visual Inspection: Periodically inspect the fuse and its holder for any signs of overheating (discoloration), corrosion, or loose connections.
- Replacement: If a fuse blows, it must be replaced with a new fuse of the exact same type and rating (FNA-1/2, 250V, 1/2A). Never attempt to repair a blown fuse.
- Cleanliness: Ensure the fuse holder and surrounding area are free from dust and debris.
Troubleshooting
The primary troubleshooting scenario for a fuse is when it blows.
Fuse Blows Immediately After Replacement:
- Check for Short Circuit: This is the most common reason. Disconnect all loads from the circuit and try replacing the fuse again. If it still blows, there is likely a short circuit in the wiring itself.
- Overloaded Circuit: The circuit may be drawing more current than the fuse (or wiring) is rated for. Reduce the load on the circuit.
- Incorrect Fuse Rating: Ensure you are using the correct FNA-1/2 (1/2 Amp) fuse. A fuse with too low an amperage rating will blow prematurely.
- Faulty Appliance/Device: An appliance or device connected to the circuit may be faulty and drawing excessive current. Disconnect devices one by one to identify the culprit.
Circuit Not Working After Fuse Replacement:
- Improper Seating: Ensure the fuse is fully and correctly seated in its holder.
- Damaged Fuse Holder: Inspect the fuse holder for bent contacts, corrosion, or other damage that might prevent proper electrical connection.
- Other Circuit Issues: The problem might not be the fuse. Check other components in the circuit, such as switches, wiring, or the device itself.
If you are unable to identify and resolve the issue, it is strongly recommended to consult a qualified electrician.
Specifications
| Attribute | Value |
|---|---|
| Model Number | FNA-1/2 |
| Brand | Cooper (Bussmann Fusetron) |
| Type | Dual-Element, Time-Delay Plug Fuse |
| Voltage Rating | 250 Volts AC (or less), 125 Volts AC (for 10kA IR) |
| Current Rating | 0.5 Amps (1/2 Amp) |
| Interrupting Rating (IR) | 35A @ 250V AC, 10kA @ 125V AC |
| Mounting Type | Surface Mount (Plug-in) |
| Item Weight | Approximately 1 Pound (for a pack) |
Warranty and Support
For specific warranty information and technical support regarding Cooper Bussmann Fusetron products, please refer to the official Cooper or Bussmann website, or contact their customer service directly. Fuses are consumable safety devices and are typically not covered by extensive warranties once installed, as their function is to sacrifice themselves to protect the circuit.
Always ensure you purchase genuine Cooper Bussmann products from authorized distributors to guarantee quality and performance.
