Table Of Content

BOSTON PUBLIC LIBRARY ^T2 3 9999 06588 185 THE COMMONWEALTH OF MASSACHUSETTS DEPARTMENT OF PUBLIC SAFETY BOARD OF FIRE PREVENTION REGULATIONS MASSACHUSETTS ELECTRICAL CODE RULES AND REGULATIONS GOVERNING THE INSTALLATION, REPAIR AND MAINTENANCE OF ELECTRICAL WIRING AND ELECTRICAL FIXTURES USED FOR LIGHT, HEAT AND POWER IN BUILDINGS AND STRUCTURES SUBJECT TO THE PROVISIONS OF SECTIONS 3 TO 60, CHAPTER 143, G. L, TER. ED., AS AMENDED FORM FPR-11 BOSTON PUBLIC LIBRARY ^ OFFICE CF THE SECRETARY STATE HOUSE, BOSTON, MASS. Rules and Regulations filed in this Office under the provisions of CHAPTER 30A as amended. DEPARTMENT OF PUBLIC SAFETY Filed by BOARD OF FIRE PREVENTION REGULATIONS - FPR-II MASSACHUSETTS ELECTRICAL CODE Date Filed NOVEMBER 9. 1972 Date Pnhlishpd DKCRMBKR 20, 1Q72 Chapter 233, sec. 75 Printed copies of rules and regulations purporting to be issued by authority of any department, commission, board or Officer of the Commonwealth orany city or town havingauthority toadopt them, or printed copies of any ordinances or town by-laws, shall be ad- mitted without certification or attestations, but if this genuineness is questioned, the court may require such certifications or attestations thereof as it deems necessary. Attestedasatruecopy JOHN DAVOREN F. X. SECRETARY OF THE COMMONWEALTH — Acts, 1950. Chap. 617. Chap.617 ^N ^^^ "^^ PROVIDE FOR RULES AND REGULATIONS RELATIVE TO THE INSTALLATION, REPAIR AND MAINTENANCE OF ELECTRICAL WIRING AND ELECTRICAL FIXTURES USED FOR LIGHT, HEAT AND POWER PURPOSES. Be it enacted, etc., asfollows: G. L. (Ter. Section 1. Chapter 143 of the General Laws is hereby Ende.w),§134L3,, amend—ed by inserting after section 3K the following sec- added. tion Section 3L. The board of fire prevention regulations mBoaakredrtuoles shall: make and promulgate, and from time to time may atinodnsr,eegtucl.a,- alter, amend and repeal, rules and regulations relative to the relative to installation, repair and maintenance of electrical wiring and installation, repair, etc., of electrical fixtures used for light, heat and power purposes in electrical buildings and structures subject to the provisions of sections wiring, etc. three to sixty, inclusive. Such regulations shall be in accordance with generally accepted standards of engineering practice, and shall be designed to provide reasonable uni- form requirements of safety in relation to life, fire and ex- plosion. Upon the making of such rules and regulations and prior to their promulgation, the board shall hold a public hearing thereon, notice of which shall be given by advertising in at least onenewspaper in each ofthe cities of Boston, Worcester, Springfield, Fall River, Lowell and L3Tin, at least ten days before said hearing. If, subsequent to their being deposited with the state secretary, as provided herein, the board on its own initiative contemplates changes in said rules and regulations, or if a petition is filed by any other person for changes therein, like notice and a hearing shall be given and held before the adoption thereof. Rules, etc., Such rules and regulations, and any alterations, amend- to be deposited with state ments or repeals thereof shall be deposited with the state secretary. secretary, and the same shall become effective when so deposited. aByn-dloarwdsinances Section 2. Upon the filing with the state secretary of the to be annulled, rules and regulations referred to in section three L of chapter etc. one hundred and forty-three of the General Laws, inserted by section one of this act, all by-laws and ordinances of cities and towns relating to the installation, repair and maintenance of electrical wiring and electrical fixtures used for light, heat and power purposes in buildings and structures subject to the provisions of sections three to sixty, inclusive, of said chapter one hundred and forty-three shall be annulled. Approved July 11, 1950. ——— 72"i TABLE OF CONTENTS Article Page Article Page 90 Introduction 1 358 Cellular Concrete Floor Raceways 157 362 Wireways 158 Chapter 1. General 363 Flat Cable Assemblies 159 364 Busways 161 100 Definitions 4 365 Cablebus 163 110 General 13 370 Outlet, Switch and Junction Boxes, and Fittings 164 Chapter 2. Wiring Design and 373 Cabinets and Cutout Boxes 171 Protection 374 Auxiliary Gutters 174 380 Switches 176 200 Use and Identification of 384 Switchboards and Grounded Conductors 18 Panelboards 179 .... 210 Branch Circuits 21 390 Prefabricated Buildings 183 215 Feeders 29 220 Branch-Circuit and Chapter 4. Equipment for Feeder Calculations 30 General Use 230 Services 42 400 Flexible Cords and Cables 184 240 Overcurrent Protection 58 402 Fixture Wires 194 250 Grounding 66 410 Lighting Fixtures, Lamp- 280 Lightning Arresters 89 holders, Lami>s, Recep- tacles and Rosettes 198 Chapter 3. Wiring Methods and 442224 AFpipxleidanEcleesctric Space Heat- 213 Materials ing Equipment 219 — 300 Wiring Methods General 426 Fixed Outdoor Electric Requirements 91 De-Icing and Snow- 305 Temporary Wiring 97 Melting Equipment 227 310 Conductors for General 430 Motors, Motor Circuits and Wiring 98 Controllers 229 318 Continuous Rigid Cable 440 Air Conditioning and Re- Supports 121 frigerating Equipment .... 263 320 Open Wiring on Insulators 123 445 Generators 272 324 Concealed Knob-and- 450 Transformers and Trans- Tube Work 126 former Vaults 273 330 Mineral Insulated-Metal 460 Capacitors 280 Sheathed Cable 128 470 Resistors and Reactors 282 331 Aluminum Sheathed Cable 129 480 Storage Batteries ,.... 283 334 Metal-Clad Cable 130 336 Nonmetallic Sheathed Chapter 5. Special Occupancies Cable 133 500 Hazardous Locations 286 337 Shielded Nonmetallic 501 Class I Installations Sheathed Cable 135 Hazardous Locations 293 338 Service-Entrance Cable 136 502 Class II Installations- 339 Underground Feeder and Hazardous Locations 303 Branch Circuit Cable .... 137 503 Class III Installations 342 Nonmetallic Extensions 138 Hazardous Locations 312 344 Underplaster Extensions .... 140 510 Hazardous Locations 346 Rigid Metal Conduit 141 Specific 316 347 Rigid Nonmetallic Conduit 143 511 Commerical Garages, 348 Electrical Metallic Tubing .. 146 Repair and Storage 316 350 Flexible Metal Conduit 148 512 Residential Storage Garages 319 351 LiquidtightFlexible 513 Aircraft Hangars 319 Metal Conduit 149 514 Gasoline Dispensing and 352 Surface Raceways 150 Service Stations 323 353 Multioutlet Assembly 152 515 Bulk-Storage Plants 325 354 Underfloor Raceways 152 516 Finishing Processes 328 356 Cellular Metal Floor 517 Health Care Facilities 333 Raceways 154 520 Theaters and Assembly 357 Structural Raceways 155 Halls 351 72-ii MASSACHUSETTS ELECTRICAL CODE Article Page Article Page 530 Motion-Picture Studios and 730 Outside Branch Circuits Similar Locations 358 and Feeders 456 540 Motion-Picture Projectors .. 361 750 Stand-By Power Generation 550 Mobile Homes and Mobile Systems 460 Home Parks 363 551 Recreational Vehicles and Recreational Vehicle Parks 375 Chapter 8. Communication Systems 555 Marinas and Boatyards 392 800 Communication Circuits .... 462 Chapter 6. Special Equipment 810 Radio and Television Equipment 467 600 Electric Signs and Outline 820 Community Antenna Tele- Lighting 394 vision and Radio Distribu- 610 Cranes and Hoists 400 tion Systems 473 620 Elevators, Dumbwaiters, Escalators, and Moving Walks 405 Chapter 9. Tables and Examples 630 Electric Welders 411 640 Sound-Recording and Tables - 477 Similar Equipment 415 Examples 489 645 Data Processing Systems .... 418 650 Organs 419 660 X-Ray Equipment 420 Index 665 Induction and Dielectric Heating Equipment 425 Index 499 670 Metal Working Machine Tools 430 680 Swimming and Wading Pools 431 Chapter 7. Special Conditions 700 Emergency Systems 438 710 Over 600 Volts—General .... 442 720 Circuits and Equipment Operating at Less Than 50 Volts 449 725 Remote-Control, Low- Energy Power, Low-Voltage Power and Signal Circuits 450 72-ii THE COMMONWEALTH OF MASSACHUSETTS DEPARTMENT OF PUBLIC SAFETY BOARD OF FIRE PREVENTION REGULATIONS MASSACHUSETTS ELECTRICAL CODE FORM FPR-n In accordance with the provisions of G, L,, C. 143^ s, 3L, the Board of Fire Prevention Regulations herewith makes thefollowing rules andregulations relativeto the installation, repair and maintenance of electrical wiring and electrical fixtures used for light, heat and power purposes inbuildings and structures subjecttothe provisions of G. L,, C. 143, ss, 3 to 60, inclusive, Riale 1, All installations, repairs and maintenance of electricalwiring and electricalfixtures used for light, heat and power purposes in buildings and structures subject to theprovisions ofSections 3 to 60, Chapter 143, G. L„ Ter, Ed,, as amended^ shall be reasonably safe to persons and property. Rule 2, Conformity ofinstallations, repairs and maintenance of electrical wiring and electrical fixtures used for light, heat and power with applicable regulations set forth in the code which is filed herewith with the Secretary ofthe Commonwealth shallbe considered as complying with these requiremjents. Rule 3, Additions or modifications to an existing installation shall be made in accordance with this code without bringing the remaining part of the installation to meet the requirements of this code. Rule 4, Where an actual hazard exists, the owner of thepropertyshallbe notifiedin writing by the authority enforcing this code. Rule 5« All references in this code to other standards shall be considered as advisory and not mandatory. Rule 6, The approving authority may be guided in his approval of specific items of equipment and ma terials contemplated by the code, by proof that such equipment and materials have been test- ed and conform to suitable recognized industry standards. MASSACHUSETTS ELECTRICAL CODE 72-iv Note: With reference to the approval of specific items of equipment and materials contemplated by the code, it is pointed out that in order to avoidthe necessityforrepetitionof examinations by different examiners, frequently with inade- quate facilities for such work, and to avoid the confusionwhich wouldresultfrom conflictingre- ports as tothe suitability of devices and materials examined for a given purpose, it is necessary that suchexaminations shouldbe made under standard conditions, and the record made generally available through promulgation byoi*- ganizations properly equipped and qualified for experimental testing, inspections of the run of goods at factories, and service-value determi- nation through field inspections. 72-1 ARTICLE 90 -— INTRODUCTION 90-1. Purpose. (a) The purpose of this Code is the practical safeguarding of persons and of buildings and their contents from hazards arising from the use of electricity for light, heat, power, radio, signalling and for other purposes. (b) 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, con- venient, or adequate for good service or future expansion of electrical use. Hazards often occur because of overloading of wiring systems by methods or usage not in conformity with the Code. This occurs because initial wiring did not provide for increases in use of electricity. For this reason it is recommended that the initial installation be adequate and that reasonable provisions for system changes be made as may be required for future in- crease in the use of electricity. (c) This Code is not intended as a design specification nor an instruc- tion manual for untrained persons. 90-2. Scope. (a) Covered. It covers the electric conductors and equipment in- stalled within or on public and private buildings and other premises, including yards, carnival and parking lots, and industrial substations; also the conductors that connect the installations to a supply of electricity, and other outside conductors adjacent to the premises; also mobile homes and recreational vehicles. (b) Not covered. It does not cover: (1) Installations in ships, watercraft, railway rolling stock, aircraft or automotive vehicles (except mobile homes and recreational vehicles). (2) Installations underground in mines. (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 communication purposes. (4) Installations of communication equipment under exclusive control of communication 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 communication, metering or for the generation, control, transformation, transmission and distribution of electric energy 72-2 MASSACHUSETTS ELECTRICAL CODE 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. (c) Special Permission. The authority having jurisdiction for enforcing the Code may grant exception for the installation of conductors and equipment, not under the exclusive control of the electric utilities and 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 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. The latter chapters supplement or amend 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. 90-4. Definitions. Article 100 contains definitions of a number of terms that are used in two or more Articles. In general, terms used only in a single Article are defined in the Article concerned. For electrical terms not defined in the Code, refer to the ANSI Standard Definitions of Electrical Terms, ANSI C-42 series. 90-5. Fundamental Rules. Throughout the Code are paragraphs which state only fundamentals or objectives of safeguarding. These are fol- lowed by paragraphs setting forth the recognized methods and detail by which the purpose and intent of the fundamental may be satisfied. Ac- cordingly, when employed, the rules stating a fundamental only will appear as the first paragraph of an Article or Section. 90-6. DELETED 90—7. Enforcement'. This code shall be used by the authority enforcing the code. The administrative authority supervising such enforcement of the code shall have the responsi- bility for making interpretations of the rules and shall accept approved or labeled equipment and materials suitable for the purpose for which they are to be used. He may decide on the approval of unlisted equipment and may grant special permission contemplated in a number of the rules. 90-8. Examination of Equipment for Safety. For approval of specific items of equipment and materials covered by the Code, examinations for safety should be made under standard conditions, and the record made generally available through promulgation by organizations properly equipped and qualified for experimental testing, inspections of the