Limited Approach Boundary

The limited approach boundary is the shock-protection distance around exposed energized electrical conductors or circuit parts, inside which an electric shock hazard exists. It is the nearest distance an unqualified person may approach unless continuously escorted by a qualified person and informed of hazards. This boundary is defined by standards like NFPA 70E and Canadian federal electrical safety rules.

In manufacturing and shop-floor settings, the limited approach boundary establishes a 'no-go' zone around live panels, open motor control centers (MCCs), energized test benches, switchgear, and temporary energized troubleshooting work. Supervisors mark this boundary during risk assessment, brief nearby workers, restrict traffic, and ensure only qualified electrical workers cross it with appropriate training and PPE. If the arc flash boundary is farther out, it governs barricading for thermal hazard exposure, while the limited approach boundary still controls shock protection. Unqualified workers performing nearby tasks are briefed to stay outside the boundary and keep tools, ladders, and body parts clear. Temporary barriers and an electrical safety watcher may be required when inadvertent entry is possible.

• ⚠️Confusing the limited approach boundary with the arc flash boundary and using the wrong distance for control measures.
• ⚠️Allowing unqualified workers to cross the boundary without continuous escort and hazard briefing, inconsistent with NFPA 70E and Canadian federal rules.
• ⚠️Failing to establish barriers or a watcher when inadvertent entry is possible, especially during troubleshooting, panel access, or maintenance in congested production areas.