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2014 NEC Questions and Answers - January 2014
Based on - NEC - 2014 Edition

NEC Questions and Answers – Based on the 2014 NEC®
January 2014

By Mike Holt for EC&M Magazine

Here’s the follow up to yesterday’s newsletter. We’re including all of the answers to the questions sent, so you can see how well you did.

Note: These questions are based on the 2014 NEC®.  The underlined text indicates a change to the Code rule for the 2014 NEC.

Q1. What are the Code requirements for marking of electrical equipment?

A1. 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)].

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

Author’s Comment:

  • 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)].

Q2. When the Code requires lockable disconnecting means, what does this mean?

A2.  Where the Code requires that a disconnecting means is lockable in the open position, the provisions for locking must remain in place whether the lock is installed or not. [110.25]

Exception: Locking provisions for cord-and-plug connected equipment don’t need to remain in place without the lock installed.

Q3. What are the NEC requirements for entrance and egress from electrical equipment working spaces?

A3. At least one entrance of sufficient area must provide access to and egress from the working space [110.26(C)(1)].
 
An entrance to and egress from each end of the working space of electrical equipment rated 1,200A or more that’s over 6 ft wide is required. The opening must be a minimum of 24 in. wide and 6½ ft high. A single entrance to and egress from the required working space is permitted where either of the following conditions is met [110.26(C)(2)]:

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

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).

Author’s Comment:

  • 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.
  • Since 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.

Q4. When multiple branch circuits are present in an enclosure, what does the Code require in regard to grouping of neutral conductors?

A4. The ungrounded and neutral conductors of multiple branch circuits must be grouped together by cable ties or similar means in every enclosure  [200.4(B)].

Ex 1: 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.

Ex 2: Grouping isn’t required if the conductors pass through a box or conduit body without any splices or terminations, or if the conductors don’t have a loop as described in 314.16(B)(1).

Author’s Comment:

  • 210.4(D) contains a similar requirement for branch circuit conductors.

Q5. What is the Code rule regarding the grouping of the conductors of multiwire branch circuits?

A5. 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)].

Ex: 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.

Author’s Comment:

  • 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.

Nec Exam Practice Questions

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Comments
  • Thank you Mike for your valuable news letters and the 2014 NEC Codes requirements.

    Jose A. Guillen  November 23 2014, 5:53 pm EST
    Reply to this comment

  • Can I install an afci breaker and the change 2 prong outlets to 3 prong outlets? Can an afci breaker be used with a gfci outlet?

    Jeff  August 1 2014, 5:12 pm EDT
    Reply to this comment

  • such articles are very good and kept me updated and I work an electrician alludado much

    nestor del canto  February 6 2014, 5:26 pm EST
    Reply to this comment

  • such articles are very good and kept me updated and I work an electrician alludado much

    nestor del canto  February 6 2014, 5:25 pm EST
    Reply to this comment


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