What is the difference between the limited and restricted approach boundaries?

The limited approach boundary is the closest an unqualified person may come without an escort. The restricted approach boundary is the closest a qualified person may come, and only with proper insulated PPE, tools, and a documented plan because of the increased risk of inadvertent contact.

Why is there no prohibited approach boundary?

NFPA 70E removed the prohibited approach boundary after the 2015 edition because it added complexity without improving safety. The restricted approach boundary is now the innermost shock-protection boundary, and direct contact with energized parts requires rated protection regardless.

Does this give the arc flash boundary too?

No. The arc flash boundary is a separate energy-based calculation tied to the incident energy reaching 1.2 cal/cm squared at the worker, which depends on available fault current and clearing time. This tool covers only the shock approach distances from Table 130.4(D)(a).

Why are there two limited approach distances?

An exposed movable conductor, such as an overhead line that can swing, requires a larger limited approach distance than a fixed circuit part that cannot move toward the worker. The table lists both so you can apply the correct one for the hazard present.

Can an unqualified worker ever cross the limited boundary?

Only when continuously escorted by a qualified person and equipped with appropriate PPE. Otherwise the limited approach boundary is the hard line an unqualified worker must stay outside of around energized equipment.

Electrical Safety Clearance Distance Calculator

Working safely near energized equipment starts with knowing how close anyone may get. This tool returns the NFPA 70E shock-protection approach boundaries for a given AC system voltage, distinguishing what a qualified worker may cross from what an unqualified worker must stay outside of, so you can mark out a safe work zone before the job starts.

How it works

The tool matches your voltage to a band in NFPA 70E Table 130.4(D)(a) and returns three distances:

limited approach (movable conductor) → unqualified must stay outside
limited approach (fixed circuit part) → smaller, for non-swinging parts
restricted approach (qualified only)  → innermost shock boundary

The limited approach boundary is the line for unqualified personnel; crossing it requires being a qualified person or being escorted by one. The restricted approach boundary is the inner line a qualified person may cross only with rated insulated PPE, insulated tools, and a documented energized-work plan.

Example and important notes

For a 480 V system the limited approach boundary for a fixed circuit part is 3 ft 6 in and the restricted approach boundary is 1 ft. For 15 kV those grow to 5 ft and 2 ft 2 in. Two cautions apply to every result. First, these are shock boundaries only — the arc flash boundary is a separate energy-based calculation and is often larger. Second, the distances are nominal table values; always work from the adopted edition of NFPA 70E, a qualified person’s hazard assessment, and an energized-work permit, and never rely on a clearance number alone in place of de-energizing where feasible.