What is the Rule for Tapping?
In the world of electrical distribution, tapping refers to the process of connecting a sub-circuit to a larger circuit, known as a feeder. This is typically done to provide power to a specific area or building. However, before connecting a tap conductor, there are certain rules and guidelines that must be followed to ensure the safety and integrity of the electrical system. In this article, we will explore the rules for tapping and what you need to know.
Types of Taps
Before we dive into the rules for tapping, it’s essential to understand the different types of taps. There are two main types: feeder taps and service drops. A feeder tap is a conductor that is tapped into a feeder circuit to provide power to a smaller circuit or sub-circuit. A service drop, on the other hand, is a conductor that connects a service entrance equipment (SE) to a building’s electrical system.
Feeders and Feeders Taps
A feeder is a circuit that supplies electrical power to multiple branches or sub-circuits. Feeders are typically identified by their ampacity and voltage rating. When creating a feeder tap, you must ensure that the ampacity of the tap conductor is not less than 10% of the feeder’s ampacity. This is known as the 10% rule.
Feeders and Service Drops
A service drop is a conductor that connects a service entrance equipment (SE) to a building’s electrical system. Service drops are typically found at the point of electrical supply, where the building’s electrical system connects to the utility company’s power grid. When creating a service drop, you must ensure that the ampacity of the service drop is not less than 50% of the feeder’s ampacity.
Safety Considerations
When working with electrical systems, safety is paramount. When tapping into a feeder or creating a service drop, there are several safety considerations that must be taken into account. These include:
• Overcurrent protection: Ensure that the tap conductor is protected by an overcurrent device that is no greater than the ampacity of the feeder.
• Grounding: Ensure that the tap conductor is properly grounded to prevent electrocution.
• Insulation: Ensure that the tap conductor is insulated to prevent electrical shock.
• Cable protection: Ensure that the tap conductor is protected from physical damage and environmental factors such as moisture and sunlight.
Rules for Tapping
Now that we have covered the basics of tapping, let’s explore the rules for tapping. The 10% rule states that the ampacity of the tap conductor must be not less than 10% of the feeder’s ampacity. Additionally, the ampacity of the tap conductor must not exceed the ampacity of the feeder.
Conclusion
In conclusion, the rule for tapping is complex and involves several factors. When creating a feeder tap or service drop, you must ensure that the ampacity of the tap conductor is not less than 10% of the feeder’s ampacity and is properly protected by overcurrent protection, grounded, insulated, and protected from physical damage and environmental factors. Remember to always follow safety protocols and guidelines when working with electrical systems.
Summary Table
| Type of Tap | Ampacity | Overcurrent Protection | Grounding | Insulation | Cable Protection |
|---|---|---|---|---|---|
| Feeder Tap | 10% of feeder ampacity | Maximum feeder ampacity | Required | Required | Required |
| Service Drop | 50% of feeder ampacity | Maximum feeder ampacity | Required | Required | Required |
Additional References
- National Electric Code (NEC)
- International Electrical Code (IEC)
- National Electric Safety Code (NESC)
- Institute of Electrical and Electronics Engineers (IEEE)
I hope this helps! Let me know if you have any further questions or need any additional information.