As usual, never consider the following commentary associated with these photos as a formal interpretation of the National Electrical Code (NEC). Without criticizing anyone or any product, the following scenarios present us with serious safety questions.
NO ROOM TO BREATHE
Dan Haley, president, RTB Contracting, Inc., Pacific, Wash., noticed this installation at a cellular communications site while working on an adjacent property. Notice that the load center is virtually covered by the coax ice bridge. Communications systems may have their own set of rules in the NEC, but that doesn't mean installers shouldn't abide by general installation rules as well.
Per 110.26 of the 2005 NEC, “Sufficient access and working space shall be provided and maintained about all electric equipment to permit ready and safe operation and maintenance of such equipment. Enclosures housing electrical apparatus that are controlled by a lock(s) shall be considered accessible to qualified persons.
“(A) Working Space. Working space for equipment operating at 600V, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized shall comply with the dimensions of 110.26(A)(1), (2), and (3) or as required or permitted elsewhere in this Code.
“(1) Depth of Working Space. The depth of the working space in the direction of live parts shall not be less than that specified in Table 110.26(A)(1) unless the requirements of 110.26(A)(1)(a), (b), or (c) are met. Distances shall be measured from the exposed live parts or from the enclosure or opening if the live parts are enclosed.”
NO PLACE FOR MISTAKES
Thomas Mason, manager of electrical engineering, ME Consultants, Akron, Ohio, took this photo in a large water plant in northern Ohio. “A piece of flexible cord was connected to a PVC-coated conduit body where splices were made with the cord extending to an explosion-proof junction box at a lower level,” Mason wrote. “Both were secured or bolted to the concrete wall. I guess they did the job this way on purpose because they wanted to positively avoid transmission of toxic fumes and isolate equipment grounds.”
Areas surrounding these types of locations are considered to be “hazardous (classified) locations,” and the rules in Art. 500 and 501 are clear. The purpose of explosion-proof apparatus used in these systems is to allow the proper types of fittings to be used as required by 501.15 in the 2005 NEC.
FPN No. 1 of 501.15 states, “Seals are provided in conduit and cable systems to minimize the passage of gases and vapors and prevent the passage of flames from one portion of the electrical installation to another through the conduit. Such communication through Type MI cable is inherently prevented by construction of the cable. Unless specifically designed and tested for the purpose, conduit and cable seals are not intended to prevent the passage of liquids, gases, or vapors at a continuous pressure differential across the seal.”
It should go without saying that using flexible cords in the manner shown is illegal.
Found a Code violation? E-mail your photos to Joe Tedesco at firstname.lastname@example.org.