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2005 NEC Changes Summary Articles 225 thru 240

Article 225. Outside Branch Circuits and Feeders

This article covers installation requirements for equipment, including conductors, located outdoors, on or between buildings, poles, and other structures on the premises. It has two parts:

  • Part I provides a listing of other articles that may provide additional requirements, addresses some general concerns, and briefly covers conductor sizing. Then it addresses conductor support, attachment, and clearances.
  • Part II addresses how many supplies you can have to a building and how to disconnect them. This includes such things as where to locate the disconnecting means and how to group them.

Part I General Requirements

  • Overhead feeder and branch circuit final spans are sometimes attached to the building through the use of masts. This new section recognizes the use of an installation method that is already widely used.
  • The text was revised to provide clarity that only raceways in wet locations are required to be raintight. For example, "raintight" fittings wouldn't be required for a raceway located in a damp location.

Part II. More Than One Building or Structure

  • New subsection permits more than one feeder or branch circuit to supply a building for the purpose of providing enhanced reliability.

Article 230 Services

This article covers the installation requirements for service conductors and equipment. The requirements of service conductors differ from those of other conductors. For one thing, service conductors for one structure cannot pass through the interior of another structure [230.3]. And you apply different rules, depending on whether a service conductor is inside or outside a structure. When are they "outside" as opposed to "inside?" The answer may seem obvious, but isn't.

It's usually good to start a service installation by deciding which conductors actually are parts of the service. What you decide here will determine how you do the rest of the job. To identify a service conductor, you must first determine whether you're dealing with a service (line side) or a load side distribution point.

Let's review the following definitions in Article 100 to understand when the requirements of Article 230 apply:

  • Service Point - The point of connection between the facilities of the serving utility and the premises wiring.
  • Service Conductors - The conductors from the service point to the service disconnecting means (service equipment, not meter). Service entrance conductors may be either overhead (service drop) or underground (service lateral).
  • Service Equipment - The necessary equipment, usually consisting of circuit breakers or switches and fuses and their accessories, connected to the load end of service conductors in a building, other structure (or an otherwise designated area) and intended to constitute the main control and cutoff of the electricity supply. Service equipment doesn't include the metering equipment, such as the meter and meter enclosure [230.66].

Conductors supplied from a battery, uninterruptible power supply system, solar photovoltaic system, generator, transformer, or phase converters aren't considered service conductors; they are feeder conductors [Article 100 Feeder].

Part I. General

  • New subsection permits more than one feeder or branch circuit to supply a building for the purpose of providing enhanced reliability.

Part IV. Service-Entrance Conductors

  • This section was revised to clarify when cable tray systems can contain service conductors, and when a separation barrier is required.

Part VI. Service Equipment - Disconnecting Means

  • The disconnecting means for transient voltage surge suppressors (TVSSs) are not counted as a service disconnecting means. This rule was necessary because there have been buildings where a TVSS was not permitted to be added, because the building already contained six service disconnecting means.
  • New subsection permits the installation of a meter disconnect switch ahead of the service disconnect.

Article 240. Overcurrent Protection

This article provides the requirements for selecting and installing overcurrent protection devices. A review of the basic concept of overcurrent protection will help you avoid confusion as we move forward. Overcurrent exists when current exceeds the rating of conductors or equipment. This can be due to overload, short circuit, or ground fault.

Part I. General

  • Text revised to clarify that the NEC requirements for overcurrent protection do not apply to supply cords of listed appliances or portable lamps. Overcurrent protection of supply cord is a product issue; therefore it rests with a qualified testing laboratory, such as Underwriters Laboratories Inc. (UL), not the NEC.
  • Additionally, text was revised to clarify that the NEC requirements for overcurrent protection do not apply to listed extension cord sets. Overcurrent protection for extension cords is a product issue; therefore it rests with a qualified testing laboratory, such as Underwriters Laboratories Inc. (UL), not the NEC.

Part II. Location

  • The word "approved" was replaced with "identified for the purpose." The result… nails, screws, or wire is no longer permitted to be used for circuit breaker handle ties. Handle ties must be identified for the purpose, which means designed by the manufacturer to perform this function.
  • New sentence confirms that the "next size up" protection device rule of 240.4(B) doesn't apply to feeder tap conductors.
  • New text clarifies that an individual transformer can supply more than a single load and the "next size up" protection of conductor rule contained in 240.4(B) is not permitted for secondary conductors.
  • New text specifies the maximum height that an overcurrent device can be installed, and still be considered "readily accessible." New text coordinates with similar language contained in 404.8(A) for switches.
  • Overcurrent devices must not be located in bathrooms of guest suites, as well as guest rooms of hotels and motels.

Mike Holt's Comment: If you desire more information about any of the above changes, be sure to order my Changes book and/or library (Video/DVD).

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