SWITCHES

A. Installation 380-1. Scope. The provisions of this article shall apply to all switches, switching devices, and circuit breakers where used as switches. 380-2. Switch Connections. (a) Three-Way and Four-Way Switches. Three-way and four-way switches shall be so wired that all switching is done only in the ungrounded circuit conductor. Where in metal raceways or metal-jacketed cables, wiring between switches and outlets shall be in accordance with Section 300-20(a). Exception: Switch loops shall not require a grounded conductor. (b) Grounded Conductors. Switches or circuit breakers shall not disconnect the grounded conductor of a circuit. Exception No. 1: Where the switch or circuit breaker simultaneously disconnects all conductors of the circuit. Exception No. 2: Where the switch or circuit breaker is so arranged that the grounded conductor cannot be disconnected until all the ungrounded conductors of the circuit have been disconnected. 380-3. Enclosure. Switches and circuit breakers shall be of the externally operable type mounted in an enclosure listed for the intended use. The minimum wire bending space at terminals and minimum gutter space provided in switch enclosures shall be as required in Section 373-6. Exception: Pendant- and surface-type snap switches and knife switches mounted on an open-face switchboard or panelboard. 380-4. Wet Locations. A switch or circuit breaker in a wet location or outside of a building shall be enclosed in a weatherproof enclosure or cabinet that shall comply with Section 373-2(a). Switches shall not be installed within wet locations in tub or shower spaces unless installed as part of a listed assembly. 380-5. Time Switches, Flashers, and Similar Devices. Time switches, flashers, and similar devices shall be of the enclosed type or shall be mounted in cabinets or boxes or equipment enclosures. Energized parts shall be barriered to prevent operator exposure when making manual adjustments or switching. ARTICLE 380 - SWITCHES 70-297 Exception: Where mounted SO they are accessible only to qualified persons and SO located in an enclosure that any energized parts within 6 inches (152 mm) of the manual adjustment or switch are covered by suitable barriers. 380-6. Position of Knife Switches. (a) Single-Throw Knife Switches. Single-throw knife switches shall be so placed that gravity will not tend to close them. Single-throw knife switches, approved for use in the inverted position, shall be provided with a locking device that will ensure that the blades remain in the open position when so set. (b) Double-Throw Knife Switches. Double-throw knife switches shall be permitted to be mounted so that the throw will be either vertical or horizontal. Where the throw is vertical, a locking device shall be provided to hold the blades in the open position when so set. (c) Connection of Knife Switches. Single-throw knife switches shall be so connected that the blades are deenergized when the switch is in the open position. Exception: Where the load side of the switch is connected to circuits or equipment, the inherent nature of which may provide a backfeed source of power. For such installations, a permanent sign shall be installed on the switch enclosure or immediately adjacent to open switches that reads: "WARNING-LOAD SIDE OF SWITCH MAY BE ENERGIZED BY BACKFEED. 380-7. Indicating. General-use and motor-circuit switches and circuit breakers, where mounted in an enclosure as described in Section 380-3, shall clearly indicate whether they are in the open "off" or closed "on" position. Where these switch or circuit breaker handles are operated vertically rather than rotationally or horizontally, the up position of the handle shall be the "on" position. Exception: Double-throw switches. 380-8. Accessibility and Grouping. (a) Location. All switches and circuit breakers used as switches shall be so located that they may be operated from a readily accessible place. They shall be so installed that the center of the grip of the operating handle of the switch or circuit breaker, when in its highest position, will not be more than 6½ feet (1.98 m) above the floor or working platform. Exception No. 1: On busway installations, fused switches and circuit breakers shall be permitted to be located at the same level as the busway. Suitable means shall be provided to operate the handle of the device from the floor. Exception No. 2: Switches installed adjacent to motors, appliances, or other equipment that they supply shall be permitted to be located higher than specified in the foregoing and to be accessible by portable means. Exception No. 3: Hookstick operable isolating switches shall be permitted at greater heights. 70-298 NATIONAL ELECTRICAL CODE (b) Voltage Between Adjacent Switches. Snap switches shall not be grouped or ganged in enclosures unless they can be so arranged that the voltage between adjacent switches does not exceed 300, or unless they are installed in enclosures equipped with permanently installed barriers between adjacent switches. 380-9. Faceplates for Flush-Mounted Snap Switches. Flush snap switches, that are mounted in ungrounded metal boxes and located within reach of conducting floors or other conducting surfaces, shall be provided with faceplates of nonconducting, noncombustible material. Metal faceplates shall be of ferrous metal not less than 0.030 inch (0.762 mm) in thickness or of nonferrous metal not less than 0.040 inch (1.016 mm) in thickness. Faceplates of insulating material shall be noncombustible and not less than 0.10 inch (2.54 mm) in thickness, but they shall be permitted to be less than 0.10 inch (2.54 mm) in thickness if formed or reinforced to provide adequate mechanical strength. Faceplates shall be installed so as to completely cover the wall opening and seat against the wall surface. 380-10. Mounting of Snap Switches. (a) Surface-type. Snap switches used with open wiring on insulators shall be mounted on insulating material that will separate the conductors at least ½ inch (12.7 mm) from the surface wired over. (b) Box Mounted. Flush-type snap switches mounted in boxes that are set back of the wall surface as permitted in Section 370-20 shall be installed so that the extension plaster ears are seated against the surface of the wall. Flush-type snap switches mounted in boxes that are flush with the wall surface or project therefrom shall be so installed that the mounting yoke or strap of the switch is seated against the box. 380-11. Circuit Breakers as Switches. A hand-operable circuit breaker equipped with a lever or handle, or a power-operated circuit breaker capable of being opened by hand in the event of a power failure, shall be permitted to serve as a switch if it has the required number of poles. Note: See provisions contained in Section 240-81 and Section 240-83. 380-12. Grounding of Enclosures. Metal enclosures for switches or circuit breakers shall be grounded as specified in Article 250. Where nonmetallic enclosures are used with metal-sheathed cables or metallic conduits, provision shall be made for grounding continuity. Metal face plates for snap switches shall be effectively grounded where used with a wiring method that includes or provides an equipment ground. 380-13. Knife Switches. (a) Isolating Switches. Knife switches rated at over 1200 amperes at 250 volts or less, and at over 600 amperes at 251 to 600 volts, shall be used only as isolating switches and shall not be opened under load. (b) To Interrupt Currents. To interrupt currents over 1200 amperes at 250 volts, nominal, or less, or over 600 amperes at 251 to 600 volts, nominal, a circuit breaker or a switch of special design listed for such purpose shall be used. ARTICLE 380 - SWITCHES 70-299 (c) General-Use Switches. Knife switches of ratings less than specified in (a) and (b) above shall be considered general-use switches. (FPN): See definition of general-use switch in Article 100. (d) Motor-Circuit Switches. Motor-circuit switches shall be permitted to be of the knife-switch type. (FPN): See definition of a motor-circuit switch in Article 100. 380-14. Rating and Use of Snap Switches. Snap switches shall be used within their ratings and as indicated in (a) through (c) below: (a) AC General-Use Snap Switch. A form of general-use snap switch suitable only for use on alternating-current circuits for controlling the following: (1) Resistive and inductive loads, including electric-discharge lamps, not exceeding the ampere rating of the switch at the voltage involved. (2) Tungsten-filament lamp loads not exceeding the ampere rating of the switch at 120 volts. (3) Motor loads not exceeding 80 percent of the ampere rating of the switch at its rated voltage. (b) AC-DC General-Use Snap Switch. A form of general-use snap switch suitable for use on either ac or dc circuits for controlling the following: (1) Resistive loads not exceeding the ampere rating of the switch at the voltage applied. (2) Inductive loads not exceeding 50 percent of the ampere rating of the switch at the applied voltage. Switches rated in horsepower are suitable for controlling motor loads within their rating at the voltage applied. (3) Tungsten-filament lamp loads not exceeding the ampere rating of the switch at the applied voltage if "T" rated. (FPN No. 1): For switches on signs and outline lighting, see Section 600-2. (FPN No. 2): For switches controlling motors, see Sections 430-83, 430-109, and 430-110. (c) CO/ALR Snap Switches. Snap switches rated 20 amperes or less directly connected to aluminum conductors shall be listed and marked CO/ALR. B. Construction Specifications 380-15. Marking. Switches shall be marked with the current and voltage and, if horsepower rated, the maximum rating for which they are designed. 380-16. 600-Volt Knife Switches. Auxiliary contacts of a renewable or quick-break type or the equivalent shall be provided on all knife switches rated 600 volts designed for use in breaking current over 200 amperes. 380-17. Fused Switches. A fused switch shall not have fuses in parallel except as permitted in Section 240-8, Exception. 70-300 NATIONAL ELECTRICAL CODE 380-18. Wire Bending Space. The wire bending space required by Section 380-3 shall meet Table 373-6(b) spacings to the enclosure wall opposite the line and load terminals.