A law firm contacted me about an incident involving safe working clearances in and around electrical equipment. The attorney asked about the working space outlined in 110.26(A)(1) through (3) of the National Electrical Code (NEC) and wanted me to explain in a written report, as well as my knowledge would permit, my opinion of the requirements pertaining to this working space. Note that I was never given any details of the incident’s cause or even what took place when the incident happened.
Application of 110.26(A)
To begin, I pointed out that the NEC requires sufficient access and working space about electrical equipment. Such a requirement ensures a safe working area for personnel, who have the task of repairing or maintaining such equipment.
I noted that the requirements of 110.26(A)(1) through (A)(3) must be followed, where the equipment is likely to require examination, adjustment, servicing or maintenance while such equipment is energized with live circuit conductors and parts. Applying the word “energized” must be done using extreme care. I told the attorney to review the definitions of “energized” and “enclosed” (as applied to live parts). Article 100 of the NEC outlines these terms. Careful review of this section makes it clear that the depth, width and height of the working space must be provided.
Conditions to working space
Next, I covered (A)(1) of 110.26 and noted that Table 110.26(A)(1) addresses two voltage levels of 0 to 150 volts and over 150 to 600 volts. Therefore, the requirements for working space in front (depth of working space) of the electrical equipment are provided to serve as an aid so that NFPA 70B and NFPA 70E can be applied appropriately. For example, Condition 1, 2 or 3 must be applied based on what might be located behind a maintenance electrician’s back. If, for instance, the voltage is 120, 120/240 or 120/208, the working space in front of the electrical equipment (panelboard) with an insulated or uninsulated wall or object located behind the worker’s back, is 3 feet as outlined in Condition 1.2 or 3 of Table 110.26(A)(1). I explained that the NEC considers concrete, brick, tile, etc., as being grounded surfaces, so the minimum working clearances of Condition 2 for 277/480 volts is increased to 3 feet in front of such equipment.
(A)(2) deals with the width of the working space and must be either 30 inches or the width of the equipment, whichever is greater. This space, when provided, permits elbowroom and other necessary space needed for switching and/or safely maintaining the components within the enclosure.
According to (A)(3), a height clearance of 6 feet must be included to prevent other crafts from installing piping or items that hinder or block a qualified worker from standing in such working zone and safely performing maintenance on the electrical equipment. In the 2011 NEC, 110.26(E) pertaining to the 6-feet rule, has been moved to 110.26(A)(3).
Where equipment is mounted over other equipment, a reach-over rule of 6 inches must also be provided, which is important to make the requirements of NFPA 70E easier to apply.
My interpretation of this section requires working space where energized conductors and circuit parts are normally enclosed and not exposed.
This working space is required so that personnel will have a safe area to inspect and service or switch devices; therefore, storage in front of such electrical equipment is strictly prohibited.
Entrance and egress
The NEC not only requires an adequate entrance but also a safe egress from working space about electrical equipment. Safe egress provides an escape path for personnel from the workspace, in case an arcing event (ground fault or short circuit) or explosion should occur.
In (C)(1), the NEC requires at least one entrance and egress path (escape path) be provided for workers to allow a clear egress from an area where a ground fault or short circuit has developed, resulting in a fire or explosion within the electrical equipment.
In (C)(2), the NEC includes the requirement that electrical equipment more than 6 feet wide and rated 1,200 amperes or greater is to be considered large equipment.
For such equipment, the NEC requires that at least a single entrance and egress path from the required working space be provided.
I never heard back from the law firm or learned the conditions involved in the incident. I also don’t know how it fared with my information. But I want readers to know that keeping working clearances in and around electrical equipment is important when an accident happens. I also would point out the signage requirements outlined in NEC 110.16 and NFPA 70E, 130.3(C).
STALLCUP is the CEO of Grayboy Inc., which develops and authors publications for the electrical industry and specializes in classroom training on the National Electrical Code and other standards, including those from OSHA. Contact him at 817.581.2206.