An ungrounded conductor is typically referred to as a “hot” or “live” conductor, meaning it carries current under normal operating conditions and has a voltage potential other than zero with respect to ground. Here are some characteristics and considerations related to ungrounded conductors:
- Potential: Ungrounded conductors have a voltage potential with respect to ground. This means that if a person or piece of equipment comes into contact with an ungrounded conductor while also being grounded, there’s a risk of electrical shock.
- Identification: The National Electrical Code (NEC) in the United States specifies color codes for identifying ungrounded conductors in different systems. For instance, in single-phase systems, they can be black and red, while in 3-phase systems, common colors include black, red, and blue.
- Multiple Circuits: In systems with multiple circuits, it’s important to ensure that the ungrounded conductors of one circuit are not accidentally connected to those of another, as this can lead to overload and other potential issues.
- Safety Precautions: When working on electrical systems, always treat ungrounded conductors as if they are live. Before performing any work, ensure the circuit is de-energized, locked out, and tested.
- Circuit Control: Ungrounded conductors are typically switched or controlled when circuits are turned on or off. This means that circuit breakers, switches, and other control devices are usually installed on the hot side (the ungrounded conductor) of the circuit.
- Use in Systems: In both single-phase and three-phase systems, it’s the ungrounded conductors that deliver power to connected loads. They are essential for the operation of any electrical equipment.
In summary, ungrounded conductors are the primary current-carrying wires in an electrical circuit and have a voltage potential relative to the ground. Proper identification, handling, and safety precautions are crucial when dealing with these conductors.