INTRODUCTION

90-1. Purpose. (a) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity. (b) Adequacy. This Code contains provisions considered necessary for safety. Compliance therewith and proper maintenance will result in an installation essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use. (FPN): Hazards often occur because of overloading of wiring systems by methods or usage not in conformity with this Code. This occurs because initial wiring did not provide for increases in the use of electricity. An initial adequate installation and reasonable provisions for system changes will provide for future increases in the use of electricity. (c) Intention. This Code is not intended as a design specification nor an instruction manual for untrained persons. 90-2. Scope. (a) Covered. This Code covers: (1) Installations of electric conductors and equipment within or on public and private buildings or other structures, including mobile homes, recreational vehicles, and floating buildings; and other premises such as yards, carnival, parking, and other lots, and industrial substations. (FPN): For additional information concerning such installations in an industrial or multibuilding complex, see the National Electrical Safety Code, ANSI C2-1990. (2) Installations of conductors and equipment that connect to the supply of electricity. (3) Installations of other outside conductors and equipment on the premises. (4) Installations of optical fiber cable. (b) Not Covered. This Code does not cover: (1) Installations in ships, watercraft other than floating buildings, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles. (2) Installations underground in mines and self-propelled mobile surface mining machinery and its attendant electrical trailing cable. (3) Installations of railways for generation, transformation, transmission, or distribution of power used exclusively for operation of rolling stock or installations used exclusively for signaling and communications purposes. 70-2 NATIONAL ELECTRICAL CODE (4) Installations of communications equipment under the exclusive control of communications utilities located outdoors or in building spaces used exclusively for such installations. (5) Installations under the exclusive control of electric utilities for the purpose of communications or metering; or for the generation, control, transformation, transmission, and distribution of electric energy located in buildings used exclusively by utilities for such purposes or located outdoors on property owned or leased by the utility or on public highways, streets, roads, etc., or outdoors by established rights on private property. (FPN): It is the intent of this section that this Code covers all premises wiring or wiring other than utility-owned metering equipment, on the load side of the service point of buildings, structures, or any other premises not owned or leased by the utility. Also, it is the intent that this Code cover installations in buildings used by the I utility for purposes other than listed in Section 90-2(b)(5) above, such as office buildings, warehouses, garages, machine shops, and recreational buildings that are not an integral part of a generating plant, substation, or control center. (c) Special Permission. The authority having jurisdiction for enforcing this Code may grant exception for the installation of conductors and equipment that are not under the exclusive control of the electric utilities and are used to connect the electric utility supply system to the service-entrance conductors of the premises served, provided such installations are outside a building or terminate immediately inside a building wall. 90-3. Code Arrangement. This Code is divided into the Introduction and nine chapters. Chapters 1, 2, 3, and 4 apply generally; Chapters 5, 6, and 7 apply to special occupancies, special equipment, or other special conditions. These latter chapters supplement or modify the general rules. Chapters 1 through 4 apply except as amended by Chapters 5, 6, and 7 for the particular conditions. Chapter 8 covers communications systems and is independent of the other chapters except where they are specifically referenced therein. Chapter 9 consists of tables and examples. Material identified by the superscript letter "x" includes text extracted from other NFPA documents as identified in Appendix A. 90-4. Enforcement. This Code is intended to be suitable for mandatory application by governmental bodies exercising legal jurisdiction over electrical installations and for use by insurance inspectors. The authority having jurisdiction for enforcement of the Code will have the responsibility for making interpretations of the rules, for deciding upon the approval of equipment and materials, and for granting the special permission contemplated in a number of the rules. The authority having jurisdiction may waive specific requirements in this Code or permit alternate methods where it is assured that equivalent objectives can be achieved by establishing and maintaining effective safety. This Code may require new products, constructions, or materials that may not yet be available at the time the Code is adopted. In such event,