This article is about Spaces about Electrical Equipment as per NEC Article 110.26 according 600 Volts, Nominal, or Less.
Electrical Equipment Spaces as Per NEC Article 110.26
In order to ensure the safe operation and maintenance of electrical equipment, 110.26 requires that adequate working space and dedicated equipment space be provided and maintained. Working space is intended to protect the worker, while dedicated equipment space is intended to provide future access to electrical equipment and to protect the equipment from intrusion by nonelectrical equipment. It is important to note that any material that blocks access or prevents safe work practices must be avoided at all times.
NEC Article 110.26 (A) Working Space
For equipment operating at 600 volts or less to ground that may require examination, adjustment, servicing, or maintenance while energized, the dimensions for working space must comply with the requirements of 110.26(A)(1), (A)(2), and (A)(3), or as specified elsewhere in the Code.
The intent of 110.26(A) is to ensure that personnel have enough space to perform any of the operations listed without endangering their safety. These operations include examining, adjusting, servicing, and maintaining equipment such as panelboards, switches, circuit breakers, controllers, and controls on heating and air-conditioning equipment. It is important to note that examination, as used in 110.26(A), includes checking for the presence of voltage using a portable voltmeter. If the equipment is such that it is not likely to require examination, adjustment, servicing, or maintenance while energized, then minimum working clearances are not required. However, access and working space are still required according to the opening paragraph of 110.26.
This section of the Code specifies the necessary working space for equipment such as panelboards, switches, circuit breakers, controllers, and controls on heating and air-conditioning equipment. The purpose of this space is to enable personnel to perform any of the listed operations without jeopardizing worker safety. Examination, as used in 110.26(A), includes checking for the presence of voltage with a portable voltmeter. If the equipment does not require examination, adjustment, servicing, or maintenance while energized, then minimum working clearances are not necessary. Nevertheless, access and working space must still be provided according to the requirements of the opening paragraph of 110.26.
NEC Article 110.26 (A)(1) Depth of Working Space
Table 110.26(A)(1) specifies the required depth of working space in relation to the exposed live parts or the enclosure or opening. This space must be at least as deep as stated in the Table, unless the requirements of 110.26(A)(1)(a), (A)(1)(b), or (A)(1)(c) are met. The distance will be measured from the exposed live parts, or from the enclosure or opening if the live parts are enclosed.
Table 110.26(A)(1) states the required depth of working space in relation to the exposed live parts or the enclosure or opening. The distance must be measured from the exposed live parts, or from the enclosure or opening if the live parts are enclosed. The minimum required depth is stated in the Table, unless one of the following conditions is met: Condition 1 – exposed live parts on one side of the working space and no live or grounded parts on the other side of the working space, or exposed live parts on both sides of the working space that are effectively guarded by insulating materials; Condition 2 – exposed live parts on one side of the working space and grounded parts on the other side of the working space (concrete, brick, or tile walls shall be considered as grounded); Condition 3 – exposed live parts on both sides of the working space.
Table 110.26(A)(1) provides the clearance requirements from the face of the equipment, based on the circuit voltage to ground, as well as whether there are grounded or ungrounded objects in the step-back space or exposed live parts across from each other. These voltages to ground are divided into two groups: 0 to 150 volts and 151 to 600 volts.
Table 110.26(A)(1) gives the clearance requirements needed when working around certain electrical systems. This includes 120/240-volt, single-phase, 3-wire; 208Y/120-volt, 3-phase, 4-wire; 240-volt, 3-phase, 3-wire; 480Y/277-volt, 3-phase, 4-wire; and 480-volt, 3-phase, 3-wire (ungrounded and corner grounded) systems. The requirements are based on the voltage of the circuit, as well as the presence of grounded or ungrounded objects in the step-back space or exposed live parts across from each other. The requirements for each of the three conditions in Table 110.26(A)(1) can be found in Exhibit 110.10. For assemblies like switchboards or motor-control centers that are accessible from the back and expose live parts, the same clearance dimensions are required at the rear of the equipment. If there is an enclosure on opposite sides of the working space, then the clearance for only one working space is needed.
NEC Article 110.26 (A)(1)(a) Dead-Front Assemblies
For dead-front assemblies like switchboards or motor control centers, working space is not necessary on the back or sides, as long as all connections and adjustable parts (like fuses or switches) can be accessed from other locations. If rear access is necessary to work on non-electrical parts on the back of enclosed equipment, then a minimum horizontal working space of 762 mm (30 in.) must be provided.
This section explains that working space is only needed from the side(s) of the enclosure that require access. Generally, equipment that needs front, rear, or side access for electrical activities must meet the requirements of Table 110.26(A)(1). However, for equipment that only needs front access, such as dead-front assemblies, a reduced working space of 762 mm (30 in.) is needed at the rear of the equipment for non-electrical activities, as illustrated in Exhibit 110.11.
NEC Article 110.26 (A)(1)(b) Low Voltage
Smaller working spaces may be allowed with special permission for equipment that operates at no more than 30 volts rms, 42 volts peak, or 60 volts dc. For existing buildings where electrical equipment is being replaced, Condition 2 working clearance may be allowed between dead-front switchboards, panelboards, or motor control centers that are located across the aisle from each other, provided written procedures are in place to prohibit the equipment on both sides of the aisle from being open at the same time and only qualified persons who are authorized will service the installation.
NEC Article 110.26 (A)(1)(c) Existing Buildings
In existing buildings where electrical equipment is being replaced, Condition 2 working clearance may be allowed between dead-front switchboards, panelboards, or motor control centers that are located across the aisle from each other, provided written procedures are in place to prohibit the equipment on both sides of the aisle from being open at the same time and only qualified persons who are authorized will service the installation.
This section allows some flexibility when upgrading electrical installations. When dead-front switchboards, panelboards, or motor-control centers are replaced in an existing building, the required working clearance is that stated in Table 110.26(A)(1), Condition 2. This reduction from Condition 3 to Condition 2 is only allowed with a written procedure in place that prohibits both doors of the equipment from being open at the same time and where only authorized and qualified personnel are servicing the installation. Exhibit 110.12 illustrates this relief for existing buildings.
NEC 110.26 (A)(2) Width of Working Space
The minimum width required for the working space in front of electrical equipment is 30 inches. This requirement applies regardless of the width of the equipment. The working space should also allow at least a 90 degree opening of equipment doors or hinged panels. If the equipment is wider than 30 inches, the working space must be equal to the width of the equipment.
The 30-in. wide front working space, which is not required to be directly centered on the electrical equipment if space is sufficient for safe operation and maintenance of such equipment. The working space can overlap other electrical equipment.
The depth of the working space must allow for a 90 degree opening of equipment doors or hinged panels. If these doors or panels are wider than 3 feet, the working space must be deeper than 3 feet to accommodate a full 90 degree opening.
NEC 110.26 (A)(3) Height of Working Space
The height of the working space must be at least 6 1/2 feet or the height of the equipment, whichever is greater. Equipment associated with the electrical installation can extend up to 6 inches beyond the front of the electrical equipment.
The electrical equipment located above or below other electrical equipment is allowed to extend up to 6 inches into the working space. This allows for the placement of a 12×12 inch wireway on the wall directly above or below a 6 inch deep panelboard. Large free-standing dry-type transformers should not be installed in the required working space for a wall-mounted panelboard as this would compromise clear access to the panelboard. Electrical equipment that produces heat or requires ventilation must also comply with 110.3(B) and 110.13.
Exception No. 1: In existing dwelling units, service equipment or panelboards with an amperage of 200 or less are allowed in spaces with a working space height less than 6 1/2 feet. Exception No. 2: Meters installed in meter sockets are permitted to extend beyond the other equipment, provided the meter socket follows the rules of this section.
NEC Article 110.26 (B) Clear Spaces
The working space required by this section (Section 110.26(B)) should not be used for storage and must be guarded when normally-enclosed live parts are exposed for inspection or servicing. When servicing or other work is done on panelboards located in corridors or passageways, access to the area around the panelboard should be restricted or guarded. Equipment that requires servicing while energized must be located in an area not used for storage.
NEC 110.26 (C) Entrance to and Egress from Working Space
NEC 110.26 (C) (1) Minimum Required
At least one entrance of sufficient size must be provided to allow access to and egress from the working space around electrical equipment. The primary purpose of this requirement is to provide a safe escape route in the event of an arc-flash incident.
NEC 110.26 (C) (2) Large Equipment
For electrical equipment rated 1200 amperes or more and wider than 1.8 meters that contains overcurrent devices, switching devices, or control devices, two entrances of at least 24 inches wide and 6 1/2 feet high must be provided at each end of the working space. Alternatively, a single entrance may be permitted if either of the conditions in 110.26(C)(2)(a) or (C)(2)(b) is met.
Where the entrance to the working space is through a door, the door must be able to swing open in the direction of egress and the door opening hardware must not require turning of a knob or other action that could impede a quick exit in case of an emergency. Exhibits 110.16, 110.17 and 110.18 provide graphical explanations of the access and entrance requirements and an example of an unacceptable hazardous work space arrangement.
A single entrance to the working space is permitted where the egress is continuous and unobstructed (110.26(C)(2)(a)), or where the depth of the working space is double the required minimum (110.26(C)(2)(b)). The entrance must be located such that the distance from the equipment to the nearest edge of the entrance is not less than the minimum clear distance specified in Table 110.26(A)(1). Exhibits 110.19 and 110.20 provide a graphical explanation of these requirements.
around electrical equipment. The lower installation would not be acceptable for a switchboard over 6 ft wide and rated 1200 amperes or more.
NEC 110.26 (C) (3) Personnel Doors
Where electrical equipment rated 1200 A or more containing overcurrent devices, switching devices, or control devices is installed and there is a personnel door within 25 feet of the working space, the door must open in the direction of egress and be equipped with panic bars, pressure plates, or other devices that open under simple pressure.
The requirements of this section apply to electrical equipment rated 1200 A or more, regardless of its width. The measurement for less than 25 feet for the personnel door is made from the nearest edge of the working space, and the requirement for panic hardware and outward egress is independent of the need for two exits from the working space. All personnel doors within 25 feet of the working space must be equipped with panic hardware and open in the direction of egress from the area (see Exhibit 110.21).
NEC 110.26 (D) Illumination
Illumination must be provided for all working spaces around service equipment, switchboards, panelboards, or motor control centers installed indoors and cannot be controlled by automated means only. Additional lighting outlets are not required when the working space is illuminated by an adjacent light source, or when it is allowed by Exception No. 1 of 210.70(A)(1) for switched receptacles.
This section was revised for the 2011 Code to require a nonautomatic means of controlling the lighting in working spaces around service equipment, switchboards, and motor control centers. Automatic lighting control devices, such as occupancy sensors, are allowed but must also have a manual bypass for the automatic control.
NEC 110.26(E) Dedicated Equipment Space
Switchboards, panelboards, and motor control centers must be located in dedicated spaces and protected from damage, except for control equipment that must be adjacent to or within sight of its operating machinery.
NEC 110.26(E)(1) Indoor
For indoor installations, the space equal to the width and depth of the equipment and extending from the floor to a height of 6 feet above the equipment or to the structural ceiling, whichever is lower, must be dedicated to the electrical installation. No piping, ducts, leak protection apparatus, or other equipment not related to the electrical installation can be located in this zone, with the exception of suspended ceilings with removable panels.
(b) Foreign Systems.
The area above the dedicated space required by 110.26(E)(1)(a) is allowed to contain foreign systems, provided protection is installed to avoid damage to the electrical equipment.
(c) Sprinkler Protection.
Sprinkler protection is allowed in the dedicated space, provided the piping complies with this section.
(d) Suspended Ceilings.
A suspended ceiling that does not add strength to the building structure is not considered a structural ceiling.
The dedicated electrical space must be clear of any piping, ducts, leak protection apparatus, or equipment foreign to the electrical installation. Busways, conduits, raceways, and cables are allowed to enter the equipment through this zone, but foreign systems installed directly above the dedicated space must include protective equipment to prevent damage to the electrical equipment below from occurrences such as leaks, condensation, and breaks.
Sprinkler protection is allowed in dedicated spaces, provided that the sprinkler piping complies with 110.26(E)(1)(c). Dropped, suspended or similar ceilings can be installed in the dedicated space, and building structural members may also be present. Electrical equipment must also be protected from physical damage, such as from personnel handling materials or the use of a forklift. Refer to 110.27(B) for additional protection requirements.
Exhibits 110.22, 110.23, and 110.24 show two distinct indoor installation spaces as required by 110.26(A) and 110.26(E): a working space and a dedicated electrical space. The dedicated electrical space, outlined by the equipment’s width and depth and extending from the floor to 6 ft above the equipment or to the structural ceiling, is reserved for electrical equipment and related conduits, cable trays, etc. The working space, located in front of the electrical equipment, must also be protected from sprinklers. An exhaust duct may be placed outside of the dedicated electrical space, avoiding the physical protection requirements of 110.26(E)(1)(b).
Exhibit 110.23 shows the working space in front of the panelboard as required by 110.26(A), which must be kept clear of all equipment. Exhibit 110.24 illustrates the dedicated electrical space above and below the panelboard as required by 110.26(E)(1), for cables, raceways, etc. running to and from the panelboard.
NEC 110.26(E) (2) Outdoor
Outdoor electrical equipment must be installed in suitable enclosures and protected from unauthorized contact, vehicular traffic, or spillage or leakage from piping systems. The working clearance space must include the zone described in 110.26(A) and must be kept free of architectural appurtenances or other equipment.
Care must be taken when adding protection from unauthorized personnel or vehicular traffic to existing installations to comply with 110.26(E)(2). Any excavation or driving of steel into the ground for fencing, vehicle stops, or bollards must be done after a thorough investigation of the below-ground wiring.
NEC 110.26 (F) Locked Electrical Equipment Rooms or Enclosures
Equipment rooms or enclosures housing electrical apparatus that are locked can still be considered accessible to qualified personnel, as long as they have access.
