Stumped by the Code? NEC Requirements for Entrance and Egress

• Only one entrance is required where the location permits a continuous and unobstructed way of egress travel [110.26(C)(2)(a)] (Fig. 2).

• Only one entrance is required where the required working space depth is doubled, and the equipment is located so the edge of the entrance is no closer than the required working space distance [110.26(C)(2)(b)] (Fig. 3).

If equipment with overcurrent or switching devices rated 800A or more is installed, personnel door(s) for entrance to and egress from the working space located less than 25 ft from the nearest edge of the working space must have the door(s) open in the direction of egress and be equipped with listed panic hardware  [110.26(C)(3)] (Fig. 4).

History has shown that electricians who suffer burns on their hands in electrical arc flash or arc blast events often can’t open doors equipped with knobs that must be turned. Because this requirement is in the NEC, the electrical contractor is responsible for ensuring that panic hardware is installed where required. Some electrical contractors are offended at being held liable for nonelectrical responsibilities, but this rule is designed to save the lives of electricians. For this and other reasons, many construction professionals routinely hold “pre-construction” or “pre-con” meetings to review potential opportunities for miscommunication — before the work begins.

Q. What is the Code rule regarding the grouping of the conductors of multiwire branch circuits?

A. The ungrounded and neutral conductors of a multiwire branch circuit must be grouped together by cable ties or similar means at the point of origination [210.4(D)].

Exception: Grouping isn’t required where the circuit conductors are contained in a single raceway or cable unique to that circuit that makes the grouping obvious or if the conductors have circuit number tags on them.

Grouping all associated conductors of a multiwire branch circuit together by cable ties or other means within the point of origination makes it easier to visually identify the conductors of the multiwire branch circuit. The grouping will assist in making sure that the correct neutral is used at junction points and in connecting multiwire branch circuit conductors to circuit breakers correctly, particularly where twin breakers are used. If proper diligence isn’t exercised when making these connections, two circuit conductors can be accidentally connected to the same phase or line.

CAUTION: If the ungrounded conductors of a multiwire circuit aren’t terminated to different phases or lines, the currents on the neutral conductor won’t cancel, which can cause an overload on the neutral conductor.

Q. What are the Code requirements for marking of electrical equipment?

A. The manufacturer’s name, trademark, or other descriptive marking must be placed on all electrical equipment and, where required by the Code, markings such as voltage, current, wattage, or other ratings must be provided. All marking must have sufficient durability to withstand the environment involved [110.21].

Where caution, warning, or danger signs or labels are required, the labels must meet the following [110.21(B)]:

• The markings must use words, colors, or symbols that effectively warn personnel  [110.21(B)(1)].

Note: ANSI Z535.4, Product Safety Signs and Labels, provides guidelines for the design and durability of signs and labels.

• The label can’t be handwritten, and it must be permanently affixed to the equipment [110.21(B)(2)].

Exception to (2): Labels that contain information that’s likely to change can be handwritten, if it’s legible.

Note: A permanently affixed sign would include a sticker but not a piece of paper taped to the equipment.

• The marking must be of sufficient durability to withstand the environment involved [110.21(B)(3)].