The limited approach boundary is a safety distance that unqualified persons must maintain when they are close to exposed energized parts of electrical equipment. This concept is crucial to ensure the safety of individuals who may not be trained in handling live electrical systems.
For an electrical system with a nominal AC voltage of less than 50 volts, phase-to-phase, the limited approach boundary for an exposed fixed circuit part is a pre-determined standard value. This value is set to ensure adequate protection against electric shock and is typically referenced in safety guidelines and standards provided by organizations such as the National Fire Protection Association (NFPA).
According to the NFPA 70E, which is the Standard for Electrical Safety in the Workplace, the limited approach boundary for a system with a nominal AC voltage of less than 50 volts, phase-to-phase, is 0.3 meters (1 foot). This distance is established to provide a safe zone around the electrical equipment, within which only qualified personnel who are trained and authorized can enter to perform maintenance or inspection tasks.
To summarize:
- For nominal AC system voltage less than 50 volts, phase-to-phase,
- The limited approach boundary for an exposed fixed circuit part is 0.3 meters (1 foot).
This distance helps to protect individuals from the potential risks associated with exposed electrical parts, ensuring a safer working environment.
