devices with integral enclosures are used, sufficient length of cable shall be provided to facilitate replacement.
V. Grounding
692.41 System Grounding.
(A) AC Systems. Grounding of ac systems shall be in accordance with 250.20, and with 250.30 for stand-alone systems.
(B) DC Systems. Grounding of dc systems shall be in ac- cordance with 250.160.
(C) Systems with Alternating-Current and Direct- Current Grounding Requirements. When fuel cell power systems have both alternating-current (ac) and direct-current (dc) grounding requirements, the dc grounding system shall be bonded to the ac grounding system. The bonding conductor shall be sized according to 692.45. A single common grounding electrode and grounding bar may be used for both systems, in which case the common grounding electrode conductor shall be sized to meet the requirements of both 250.66 (ac) and 250.166 (dc).
692.44 Equipment Grounding Conductor. A separate equipment grounding conductor shall be installed.
692.45 Size of Equipment Grounding Conductor. The equipment grounding conductor shall be sized in accor- dance with 250.122.
692.47 Grounding Electrode System. Any auxiliary grounding electrode(s) required by the manufacturer shall be connected to the equipment grounding conductor specified in 250. 118.
VI. Marking
692.53 Fuel Cell Power Sources. A marking specifying the fuel cell system, output voltage, output power rating, and continuous output current rating shall be provided at the disconnecting means for the fuel cell power source at an accessible location on the site.
692.54 Fuel Shut-Off. The location of the manual fuel shut-off valve shall be marked at the location of the primary disconnecting means of the building or circuits supplied.
692.56 Stored Energy. A fuel cell system that stores electric energy shall require the following warning sign, or equivalent, at the location of the service disconnecting means of the premises:
WARNING FUEL CELL POWER SYSTEM CONTAINS ELECTRICAL ENERGY STORAGE DEVICES.
VII. Connection to Other Circuits
692.59 Transfer Switch. A transfer switch shall be re- quired in non-grid-interactive systems that use utility grid backup. The transfer switch shall maintain isolation between the electrical production and distribution network and the fuel cell system. The transfer switch shall be permitted to be located externally or internally to the fuel cell system unit. When the utility service conductors of the structure are connected to the transfer switch, the switch shall comply with Article
230, Part V.
692.60 Identified Interactive Equipment. Only fuel cell systems listed and identified as interactive shall be permitted in interactive systems.
692.61 Output Characteristics. The output of a fuel cell system operating in parallel with an electric supply system shall be compatible with the voltage, wave shape, and frequency of the system to which it is connected.
FPN: The term compatible does not necessarily mean matching the primary source wave shape.