Top 50 NEC Rules

408.4 Circuit Directory or Circuit Identification By Mike HoltAll circuits and circuit modifications must be legibly identified as to their clear, evident, and specific purpose. The identification must include sufficient detail to allow each circuit to be distinguished from all others, and the identification must be on a circuit directory located on the face or inside of the door of a panelboard.

406.8 Receptacles in Damp or Wet Locations By Mike HoltDamp Locations. Receptacles installed outdoors under roofed open porches, canopies, marquees, and the like (and not subject to beating rain or water runoff or in other damp locations) must be installed in an enclosure that is weatherproof when the attachment plug cap isn't inserted and receptacle covers are closed.

A receptacle installed within an enclosure that is weatherproof when an attachment plug is inserted is also suitable for a damp location. See Art. 100 for the definition of "Location, Damp."

Wet Locations. All 15A and 20A, 125V and 250V receptacles installed in a wet location must be within an enclosure that is weatherproof even when an attachment plug is inserted. Receptacles rated other than 15A or 20A, 125V or 250V installed in a wet location must comply with (a) or (b):

a. Wet location cover. A receptacle installed in a wet location, where the load isn't attended while in use, must have an enclosure that is weatherproof with the attachment plug cap inserted or removed.

b. Damp location cover. A receptacle installed in a wet location for use with portable tools can have an enclosure that is weatherproof when the attachment plug is removed.

Bathtub and Shower Spaces. Receptacles must not be installed within or directly over a bathtub or shower stall. Receptacles must be located no less than 5 feet from any spas or

hot tubs [680.22(A)(1) and 680.43(A)(1)]. Hydromassage bathtubs are treated like bathtubs [680.70].

Flush Mounting with Faceplate. The enclosure for a receptacle installed in an outlet box that is flush-mounted on a finished surface must be made weatherproof by a weatherproof faceplate that provides a watertight connection between the plate and the finished surface.

Code Quiz By Steven OwenQ. In a large electrical room with numerous pieces of equipment rated at 1,200A or more, the question has arisen as to whether panic hardware is or is not required on all of the personnel doors. One personnel door is located 30 feet from the nearest edge of the switchgear, which is rated at 2,000A. The other personnel door is located 3 feet from the nearest edge of the motor control center, which is rated at 1,600A. There is also a roll-up door for moving equipment in and out of the room. Per the 2008 version of the NEC, which one of the following is the correct answer?

A. All personnel doors must have panic hardware and open in the direction of egress. In this example, it would include both the personnel doors.

B. All personnel and equipment doors must have panic hardware. C. All personnel doors located within 25 feet of electrical equipment rated 1,200A or

greater must have panic hardware, and open in the direction of egress. In this example, it would only include the personnel door located within 3 feet of the motor control center.

D. Section 110.26(C)(3) would not apply in this example because the width of the electrical equipment is not known. This section of the Code applies only to equipment that is rated 1,200A or greater, and more than 6 feet in width.

Top 50 NEC Rules

314.29 Wiring to be Accessible By Mike HoltBoxes, conduit bodies, and handhole enclosures must be installed so that the wiring is accessible without removing any part of the building, sidewalks, paving, or earth.

Exception: Listed boxes and handhole enclosures can be buried if covered by gravel, light aggregate, or non-cohesive granulated soil, and their location is effectively identified and accessible for excavation.

Code Challenge

What's Wrong Here? Think you know how this installation violates the NEC? Visit EC&M 's Web site to see the answer.

Hint: New water feature.

Code Q&A By Mike HoltQ. A single main breaker is installed, then taps supply individual meters with disconnecting means for individual tenants. Should a main bonding jumper be installed at the single main breaker or at each separate disconnect?

Visit EC&M 's Web site to see the answer.

Code Quiz By Steven OwenQ. What is the maximum allowable ampacity of a 10 AWG THHN or THWN-2 insulated conductor installed in a schedule 80 PVC raceway (90°C rated) installed underground from the branch-circuit panelboard to the luminaires installed for parking lot lighting? There are four current-carrying conductors in this raceway. Disregard the terminals and the branch-circuit rating for this example.

A. 32A B. 30A C. 28A D. 24A