NEC Annex I provides recommended tightening torque values for various electrical connections. These guidelines are essential to ensure that electrical connections are secure and safe, preventing issues such as overheating, arcing, and potential failures.

1. Purpose

Annex I is designed to offer recommended torque values for tightening screws, bolts, and other types of connectors used in electrical installations. Proper torque ensures good electrical contact and mechanical integrity.

2. Importance of Proper Torque

Using the correct torque values helps to:

• Ensure reliable and stable electrical connections.
• Prevent damage to connectors and terminals.
• Avoid issues such as loose connections that can lead to overheating and electrical fires.

3. Tables and Torque Values

Annex I includes tables that provide the recommended torque values for different types of connections. These tables cover a wide range of connectors and applications, including:

• Copper and Aluminum Conductors: Torque values for connectors used with both copper and aluminum conductors.
• Screw and Bolt Sizes: Specific torque values based on the size and type of screw or bolt used in the connection.
• Manufacturer Specifications: Guidance on following manufacturer-recommended torque values when available, as these are tailored to specific products and applications.

4. Application Guidelines

Annex I also provides guidelines on how to apply these torque values correctly:

• Tools: Use properly calibrated torque tools to achieve the specified torque values.
• Manufacturer Instructions: Always follow the manufacturer’s instructions for specific products, as these may have unique requirements.
• Inspection: Regularly inspect and maintain connections to ensure they remain secure over time.

Example Torque Values (Illustrative Purposes Only)

• #10 Screw, Copper Conductor: 25 in-lbs
• 1/4″ Bolt, Aluminum Conductor: 50 in-lbs
• 3/8″ Bolt, Copper Conductor: 120 in-lbs

These values are illustrative and should be verified with the actual tables in Annex I for specific applications.

For more detailed information and specific guidelines, it is recommended to consult the NEC Handbook and additional resources provided by the NFPA. Further insights can be found on NFPA’s official site and other electrical safety resources.