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<br />(a) General. Metal raceways, cable trays, cable armor, cable sheath, enclosures, frames, fittings, and other <br />metal noncurrent-carrying parts that are to serve as grounding conductors, with or without the use of <br />supplementary equipment grounding conductors, shall be effectively bonded where necessary to ensure <br />electrical continuity and the capacity to conduct safely any fault current likely to be imposed on them. Any <br />nonconductive paint, enamel, or similar coating shall be removed at threads, contact points, and contact surfaces <br />or be connected by means of fittings designed so as to make such removal unnecessary. <br /> <br />(b) Isolated Grounding Circuits. Where required for the reduction of electrical noise (electromagnetic <br />interference) on the grounding circuit, an equipment enclosure supplied by a branch circuit shall be permitted to <br />be isolated from a raceway containing circuits supplying only that equipment by one or more listed nonmetallic <br />raceway fittings located at the point of attachment of the raceway to the equipment enclosure. The metal <br />raceway shall comply with provisions of this article and shall be supplemented by an internal insulated <br />equipment grounding conductor installed in accordance with Section 250-146( d) to ground the equipment <br />enclosure. <br /> <br />FPN: Use ofan isolated equipment grounding conductor does not relieve the requirement for grounding the raceway system. <br /> <br />w~'-'--'il <br />,TcOllliftental .. <br /> <br />. . 250-97. Bonding for Over 250 Volts <br /> <br />For circuits of over 250 volts to ground, the electrical continuity of metal raceways and cables with metal <br />sheaths that contain any conductor other than service conductors shall be ensured by one or more of the methods <br />specified for services in Section 250-94 except for (1). <br /> <br />Exception: Where oversized, concentric, or eccentric knockouts are not encountered, or where a box or <br />enclosure with concentric or eccentric knockouts is listed for the purpose, the following methods shall be <br />permitted: <br /> <br />a. Threadless couplings and connectors for cables with metal sheaths <br /> <br />b. Two locknuts, on rigid metal conduit or intermediate metal conduit, one inside and one outside of boxes <br />and cabinets <br /> <br />c. Fittings with shoulders that seat firmly against the box or cabinet, such as electrical metallic tubing <br />connectors, flexible metal conduit connectors, and cable connectors, with one locknut on the inside of boxes and <br />cabin~ts <br /> <br />d Listedfitting.;s ,.,-.,-",',~^C"-__m._..;u.'w..,. <br />',C__t.., .. <br />: to. __. ,. __,. <br /> <br />.. 250-98. Bonding Loosely Jointed Metal Raceways <br /> <br />Expansion fittings and telescoping sections of metal raceways shall be made electrically continuous by <br />equipment bonding jumpers or other means. <br /> <br />..250-100. Bonding in Hazardous (Classified) Locations <br /> <br />Regardless of the voltage of the electrical system, the electrical continuity of noncurrent-carrying metal parts of <br />equipment, raceways, and other enclosures in any hazardous (classified) location as defined in Article 500 shall <br />be ensured by any of the methods specified for services in Section 250-94 that are approved for the wiring <br />method used. <br />