While the National Electrical Code does not mandate maximum or minimum installation heights for most equipment, one exception is switches with fuses and circuit breakers, which have installation and operational height limitations. Sufficient working spaces are also important to workplace safety, yet their requirements in the NEC seem like the bare minimum—but that’s a topic for another time. 

This article provides a closer review of NEC requirements that specifically address the maximum heights for switches and circuit breakers as they correlate with requirements that promote ready access for occupants and operators.

Accessible and readily accessible

The NEC has requirements for overcurrent protective devices (OCPDs) that generally call for them to be “readily accessible.” The term “accessible, readily (readily accessible)” is defined in Article 100 as “capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to take actions such as the use of tools (other than keys), to climb over or under, to remove obstacles, or to resort to portable ladders and so forth.” The use of keys to gain access to electrical equipment is common and a Code-recognized alternative in more controlled or supervised conditions such as industrial or commercial facilities that often have qualified personnel. 

The definition of the general term “accessible (as applied to equipment)” does have the same restrictions as equipment required to be readily accessible. The term as it applies to equipment more simply means that the equipment is capable of being accessed or reached for operation, renewal, resetting, inspection and so forth. 

NEC height requirements

The Code rule that addresses minimum or maximum height requirements is Section 110.26(A)(3). It indicates that the minimum height required for the working space is to be not less than 2.0 m (6.5 feet) or not less than the height of the equipment, whichever is greater. Within this rule, there is an allowance for other equipment or structures to be located above or below the equipment, but they cannot extend more than 150 mm (6 inches) beyond the front of the equipment. This is the rule that permits concrete mounting or housekeeping pads and electrical equipment such as wireways and junction or pull boxes to be in that space (above and below) if they are associated with the electrical installation. 

Section 110.26(E) addresses some height requirements for dedicated space above service equipment, switchboards, panelboards, switchgear and motor control centers. The basic rule for both indoor and outdoor installations is that the space 1.8 m (6 feet) above the equipment be dedicated to the electrical installation. The measurement is to the structural ceiling if it is located less than 1.8 m (6 feet) above the equipment. No piping, ducts or leak protection apparatus foreign to the electrical installation is allowed in this dedicated space. 

Exceptions to this general rule are for suspended ceiling frames with removable panels. Remember that a suspended ceiling that does not add structural strength is not considered a structural ceiling. The area above the dedicated space is permitted to contain foreign systems, provided protection is afforded to avoid damage from leaks or breaks in any of these foreign systems. 

The next maximum height requirements are found in sections 240.24(A) and 404.8(A), which address accessibility. The general requirement is that switches containing fuses and circuit breakers shall be readily accessible and installed so that the center grip of the equipment handle is not higher than 2.0 m (6 feet, 7 inches) above the floor or working platform. 

Alternatives to 240.24(A) permit this equipment at heights greater than these rules. The first is for switches installed on busways in accordance with 368.17(C), and the second is for supplementary overcurrent protection as addressed in 240.10. The third allowance is for OCPDs as described in sections 225.40 and 230.92, which both address feeder and service OCPDs that are not readily accessible to occupants, but the branch circuit or feeder OCPDs are readily accessible to the occupants. The fourth allowance is for OCPDs adjacent to the utilization equipment they supply, such as motors. Alternative height allowances are also provided in 404.8(A)(1), (2) and (3).  

The NEC does not generally provide minimum or maximum heights for equipment; however, the maximum height allowed for circuit breakers and switches containing fuses is not to exceed 2.0 m (6 feet, 7 inches) to the center grip of the handle unless otherwise described in 240.24(A) and 404.8(A). 

Additionally, Annex J contains information about ADA standards for accessible designs, which also addresses equipment heights.

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