Last edit: 05/01/2024
Chapter 11 – Control Equipment: Location, Mounting, and Enclosures of the new edition of Industrial Machinery NFPA 79 clarifies the spaces to be maintained in front of the industrial control panel, which are necessary for a safe maintenance of industrial machines.
Article 11.5.1.1 clarifies the minimum distances, necessary in front of the industrial control panel, distinguishing 3 possible conditions:
Condition 1 — Exposed live parts on one side and no live or grounded parts on the other side of the working space, or exposed live parts on both sides effectively guarded by insulating materials. Insulated wire or insulated busbars operating at not over 300 volts to ground shall not be considered live parts.
Condition 2 — Exposed live parts on one side and a grounded surfaceon the other side. Concrete, brick, or tile walls shall be considered as grounded.
Condition 3 — Exposed live parts on both sides of the working space (not guarded as provided in Condition 1) with the operator between.
Important is the definition of Exposed Live Parts:
3.3.42 Exposed (as applied to live parts). Capable of being inadvertently touched or approached nearer than a safe
distance by a person. It is applied to parts not suitably guarded, isolated, or insulated.
The definition is the same as NFPA 70E. The problem is that "Exposed Live Parts" would be spontaneously translated into "non-IPxxB".
Unfortunately, there is no consensus on this point among the members of the working group. In particular the NFPA 79 committee does not agree to associate this definition with "Non finger Safe".