Murray MPA120AF AFCI Breaker User Manual

1. Introduction

This manual provides essential information for the safe and effective installation, operation, and maintenance of the Murray MPA120AF Arc Fault Circuit Interrupter (AFCI) breaker. The MPA120AF is a 20-amp, single pole, 120-volt, plug-on type branch feeder style AFCI breaker designed to enhance electrical safety in residential and commercial applications.

An AFCI is a device specifically engineered to detect and mitigate high current arcing faults within an electrical circuit. These faults, which can occur from line-to-neutral or line-to-ground, are often undetectable by standard circuit breakers and can lead to electrical fires. The MPA120AF de-energizes the circuit when an arc fault is detected, significantly reducing fire hazards. It also features an exclusive LED light to indicate the type of trip, aiding in diagnostics.

Figure 1: Murray MPA120AF 20-amp AFCI Breaker. This image shows the front view of the circuit breaker, highlighting its compact design and labeling.

2. Important Safety Information

WARNING: Electrical shock hazard. This product must be installed and serviced by a qualified electrician in accordance with all national and local electrical codes. Failure to follow these instructions can result in serious injury or death.

• Always disconnect power at the main service panel before working on electrical circuits or equipment.
• Use appropriate personal protective equipment (PPE), including insulated gloves and safety glasses.
• Verify that the voltage and current ratings of the breaker match the requirements of the circuit it will protect.
• Do not install in wet or damp locations unless specifically rated for such environments.
• Ensure all connections are tight and secure to prevent overheating and arcing.
• Never bypass or tamper with the AFCI breaker's protective mechanisms.

3. Package Contents

Upon opening the package, verify that the following items are present:

• 1 x Murray MPA120AF 20-amp AFCI Breaker
• 1 x Instruction Sheet (this document or similar)

If any items are missing or damaged, contact your supplier immediately.

4. Installation Instructions

NOTE: Installation must be performed by a qualified electrician. Refer to the wiring diagram provided with your electrical panel and local electrical codes.

1. Power Disconnection: Before beginning any work, ensure that the main power supply to the electrical panel is completely disconnected and locked out according to safety procedures. Verify with a voltage tester.
2. Identify Slot: Locate an available slot in your electrical panel compatible with a plug-on type breaker.
3. Connect Neutral Wire: Connect the white (neutral) pigtail wire from the AFCI breaker to the neutral bus bar in the panel. Ensure a secure connection.
4. Connect Load Neutral Wire: Connect the neutral wire from the circuit you are protecting to the designated neutral terminal on the AFCI breaker.
5. Connect Load Hot Wire: Connect the hot (black or colored) wire from the circuit you are protecting to the designated load terminal on the AFCI breaker.
6. Install Breaker: Align the AFCI breaker with the bus bar in the electrical panel and firmly push it into place until it is securely seated. The "plug-on" design ensures proper connection to the hot bus.
7. Verify Connections: Double-check all wire connections for tightness and correct placement.
8. Restore Power: Once installation is complete and verified, close the panel cover and restore power to the main service panel.

5. Operating Instructions

5.1 Normal Operation

In normal operating conditions, with no arc faults detected, the Murray MPA120AF AFCI breaker will remain in the "ON" position, allowing current to flow to the protected circuit. The breaker is designed to trip only when an arc fault or an overload/short circuit condition is detected.

5.2 Testing the AFCI Breaker

It is recommended to test the AFCI breaker monthly to ensure proper functionality. To test:

1. Ensure the circuit is under normal load.
2. Press the "TEST" button located on the front of the breaker.
3. The breaker should immediately trip to the "OFF" position.
4. To reset, push the handle completely to the "OFF" position, then to the "ON" position.
5. If the breaker does not trip when the test button is pressed, it may be faulty and should be replaced by a qualified electrician.

5.3 LED Indicator

The MPA120AF features an exclusive LED light that indicates the type of trip, assisting in diagnosing the fault. Consult the breaker's label or manufacturer's documentation for specific LED flash codes and their meanings (e.g., 1 flash for series arc, 2 flashes for parallel arc, 3 flashes for ground fault, etc.).

6. Maintenance

The Murray MPA120AF AFCI breaker is designed for maintenance-free operation. However, periodic checks are recommended:

• Monthly Testing: Perform the test button procedure monthly as described in Section 5.2.
• Visual Inspection: Annually, or during any electrical panel service, have a qualified electrician visually inspect the breaker for any signs of damage, discoloration, or loose connections.
• Cleaning: Ensure the area around the breaker within the electrical panel remains clean and free of dust or debris. Do not use liquids for cleaning inside the panel.

Do not attempt to repair a faulty breaker. Replace it with a new, equivalent unit.

7. Troubleshooting

If your Murray MPA120AF AFCI breaker trips, follow these steps:

1. Identify Tripped Breaker: Locate the AFCI breaker that has tripped to the "OFF" position.
2. Check LED Indicator: Observe the LED indicator for flash codes to determine the type of fault (e.g., arc fault, overload).
3. Disconnect Appliances: Unplug or turn off all appliances and lights on the affected circuit.
4. Reset Breaker: Push the breaker handle completely to the "OFF" position, then firmly to the "ON" position.
5. Isolate Fault: If the breaker immediately trips again, there is likely a persistent fault (e.g., short circuit, severe arc fault) in the wiring or a connected device. Keep the breaker off and contact a qualified electrician.
6. Reconnect Devices: If the breaker holds, plug in or turn on devices one by one to identify the faulty appliance or section of wiring. If a specific device causes the trip, discontinue its use and have it inspected or replaced.
7. Persistent Arc Faults: If the LED indicates an arc fault and you cannot identify a faulty appliance, there may be damaged wiring within the walls. This requires immediate attention from a qualified electrician.

Example from user experience: One user reported that their AFCI tripped twice, leading them to discover a lamp with an arcing and melted light socket. Fixing the lamp resolved the tripping issue. This highlights the AFCI's effectiveness in detecting hidden electrical hazards.

8. Specifications

9. Warranty and Support

Specific warranty details for the Murray MPA120AF AFCI breaker are typically provided at the point of purchase or within the product packaging. For detailed warranty information, please refer to the documentation included with your product or visit the official Murray (Siemens) website.

For technical support, troubleshooting assistance beyond this manual, or to inquire about replacement parts, please contact Murray customer service. Contact information can usually be found on the manufacturer's website or product packaging.

Online Resources: For additional information, product updates, and FAQs, visit the official Murray or Siemens electrical products website.