Chapter Corner

Code Q&A - November/December 2013

Posted in: Code Corner, November/December 2013

Question:

How high should overcurrent devices be installed and in what locations?

Elec@Box.pngAnswer:

According to the National Electrical Code (NEC) 240.24 (A), location in or on premises require that overcurrent devices be “readily accessible” and shall be installed so that the center of the grip of the operating handle of the disconnecting switch or circuit breaker, when in its highest position, is not more than 2.0 m (6 feet 7 inches) above the floor or working platform unless one of the following applies:

  1. For busways, as provide in 368.17 (C).
  2. For supplementary overcurrent protection, as described in 240.10.
  3. For overcurrent devices, as described in 225.40 and 230.92.
  4. For overcurrent devices adjacent to utilization equipment that they supply, access shall be permitted to by portable means.

The definition of “readily accessible” in Article 100 of the NEC reads:

Accessible, Readily (Readily Accessible). Capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders.

240.24 (B) Occupancy

Each occupant shall have ready access to all over- current devices protecting the conductors supplying that occupancy, unless otherwise permitted in 240.24 (B) (1) and (B)(2).

(B)(1) Service and Feeder Overcurrent Devices.

Where electric service and electrical maintenance are provided by the building management and where these are under continuous building management supervision, the service overcurrent devices and feeder overcurrent devices supplying more than one occupancy shall be permitted to be accessible only to authorized management personnel in the following:

(1) Multiple-occupancy buildings.

(2) Guest rooms or guest suites.

(B)(2) Branch-Circuit Overcurrent Devices.

Where electric service and electrical maintenance are provided by the building management and where these are under continuous building management supervision, the branch-circuit overcurrent devices supplying any guest rooms or any guest suites without permanent provisions for cooking shall be permitted to be accessible only to authorized personnel.

240.24 (C) Not Exposed to Physical Damage.

Overcurrent devices shall not be located where they will be exposed to physical damage. Informational Note: See 110.11 Deteriorating Agents.

240.24 (D) Not in Vicinity of Easily Ignitable Materials. Overcurrent devices shall not be located in the vicinity of easily ignitable materials, such as clothes closets.

240.24 (E) Not Located in Bathrooms. In dwelling units, dormitories, and guest rooms or guest suites, overcurrent devices, other than supplementary over-current protection, shall not be located in bathrooms.

240.24 (F) Not Located Over Steps. Overcurrent devices shall not be located over steps of a stairway.

Marc Ramirez has been a member of the NEC Code Making Panel 17 since 1993 and is a member of the IEC National Codes and Standards Committee. He can be reached at (623) 256-9331. Submit your questions to xmrelectric@yahoo.com.