OPTIONAL STANDBY SYSTEMS

A. General 702-1. Scope. The provisions of this article apply to the installation and operation of optional standby systems. The systems covered by this article consist only of those that are permanently installed in their entirety, including prime movers. 702-2. Optional Standby Systems. Optional standby systems are intended to protect private business or property where life safety does not depend on the performance of the system. Optional standby systems are 70-734 NATIONAL ELECTRICAL CODE intended to supply on-site generated power to selected loads either automatically or manually. (FPN): Optional standby systems are typically installed to provide an alternate source of electric power for such facilities as industrial and commercial buildings, farms, and residences, and to serve loads such as heating and refrigeration systems, data processing and communications systems, and industrial processes that, when stopped during any power outage, could cause discomfort, serious interruption of the process, damage to the product or process, or the like. 702-3. Application of Other Articles. Except as modified by this article, all applicable articles of this Code shall apply. 702-4. Equipment Approval. All equipment shall be approved for the intended use. 702-5. Capacity and Rating. An optional standby system shall have adequate capacity and rating for the supply of all equipment intended to be operated at one time. Optional standby system equipment shall be suitable for the maximum available fault current at its terminals. (FPN): The optional standby system rating need only be sufficient to carry loads selected by the user. 702-6. Transfer Equipment. Transfer equipment shall be suitable for the intended use and so designed and installed as to prevent the inadvertent interconnection of normal and alternate sources of supply in any operation of the transfer equipment. Transfer equipment, located on the load side of branch-circuit protection, shall be permitted to contain supplementary overcurrent protection having an interrupting rating sufficient for the available fault current that the generator can deliver. 702-7. Signals. Audible and visual signal devices shall be provided, where practicable, for the following purposes: (a) Derangement. To indicate derangement of the optional standby source. (b) Carrying Load. To indicate that the optional standby source is carrying load. 702-8. Signs. (a) Standby. A sign shall be placed at the service-entrance equipment indicating type and location of on-site optional standby power sources. (b) Grounding. Where the grounded circuit conductor connected to the emergency source is connected to a grounding electrode conductor at a location remote from the emergency source, there shall be a sign at the grounding location that shall identify all emergency and normal sources connected at that location. B. Circuit Wiring 702-9. Wiring Optional Standby Systems. The optional standby system wiring shall be permitted to occupy the same raceways, cables, boxes, and cabinets with other general wiring.