Published In February 2000
Relocating the requirements for dedicated space below and above switchboards, panelboards, and motor control centers from Sec. 384-4 to Sec. 110-26 (110-16 in the '96 NEC logically combines these requirements with their related working space. The requirement for dedicated space above the equipment in 110-26(f) has been revised to be more practical. Now, it emphasizes protecting the equipment against falling liquids, rather than on determining the space requirements for possible future raceway entries into the top of the equipment. The clear space required above the equipment has been reduced from 25 feet to 6 feet, or to the structural ceiling, whichever is lower. Within this area, no piping, ducts, or foreign equipment (other than fire sprinklers) is permitted unless drip protection is provided. Relatedly, a piece of commercial cooking equipment was described at a recent IAEI chapter meeting. The 100 percent stainless steel exterior facilitates cleaning. The entire unit displays a nameplate on the front describing required voltage and amperes, as well as a nationally recognized third-party testing laboratory's label. Below counter level and behind a stainless steel door is a stock circuit breaker panelboard, with its front edge slightly less than six inches behind the back of the outer steel door. Questions were raised regarding the working space required by Section 110-26(a)(1), depth, (2), width, and (3), height, about this panelboard. The outer stainless steel door is just wide enough to allow the panelboard cover to open 90 degrees as required by 110-26(a)(2). A change in the '99 NEC in Sec. 110-26(a)(3) reads: "(3) Height of Working Space. The work space shall be clear and extend from the grade, floor, or platform to the height required by Section 110-26(e). Within the height requirements of this section, other equipment associated with the electrical installation located above or below the electrical equipment shall be permitted to extend not more than 6 inches (153 mm) beyond the front of the electrical equipment." Although this could be used to justify the cooking equipment below and above the front working space, this change was obviously intended to address something associated with the panelboard, such as an auxiliary gutter-not an entire piece of equipment surrounding the panelboard above, below, to the front, and to both sides. Opinions were divided. Some reasoned that, since there was a label on the exterior of the equipment, the "enclosure front" was the outer stainless steel door. Others interpreted the rules as applying to the panelboard itself. In that case, none of the requirements would be met, because parts of the equipment infringe upon the working space in front, the required minimum 30 inches of elbow room, and the head room above the working space in front of the panelboard. I would be interested in hearing your opinion on this one. A similar situation exists in the official drawings issued by one of our large utility companies. These drawings permit for the location of residential metering a recess containing a self-contained meter, with the service disconnect or service panelboard below it. These recesses are rarely more than 20 inches wide and, when measured from the front of the electrical enclosure, as required, none of the working space requirements are met. To accommodate the depth of the meter, the face of the panelboard is generally 10 to 12 inches behind the outer door and the building wall. These recesses provide the user with an attractive electrical service equipment arrangement, but they simply do not meet the working space requirements of the NEC. The authority having jurisdiction would have a difficult time requiring that the electrical panel be flush or surface mounted, when the utility permits this much more attractive recess for mounting the service equipment. At least most of these are framed in wood, in which case your elbows may not be up against a grounded surface, as they would be in the case of the kitchen equipment described above. SCHWAN is an electrical code consultant in Hayward, Calif. He can be reached at firstname.lastname@example.org.