ORD 1869 - Laserfiche WebLink

(B) Ampacity and Over current Device Ratings. Photo- voltaic system currents shall be considered continuous. (1) Sizing of Conductors and over current Devices. The circuit conductors and over current devices shall be sized to carry not less than 125 percent of the maximum currents as computed in 690.8(A). The rating or setting of over current devices shall be permitted in accordance with 240.4(B) and Exception: Circuits containing an assembly, together with its over current device(s), that is listed for continuous operation at 100 percent of its rating shall be permitted to be utilized at 100 percent of its rating. (2) Internal Current Limitation. Over current protection for photovoltaic output circuits with devices that internally limit the current from the photovoltaic output circuit shall be permitted to be rated at less than the value computed in 690.8(B)(1). This reduced rating shall be at least 125 per- cent of the limited current value. Photovoltaic output circuit conductors shall be sized in accordance with 690.8(B)(1). Exception: An over current device in an assembly listed for continuous operation at 100 percent of its rating shall be permitted to be utilized at 100 percent of its rating. (C) Systems with Multiple Direct-Current Voltages. For a photovoltaic power source that has multiple output circuit voltages and employs a common-return conductor, the ampacity of the common-return conductor shall not be less than the sum of the ampere ratings of the over current de- vices of the individual output circuits. (D) Sizing of Module Interconnection Conductors. Where a single over current device is used to protect a set of two or more parallel-connected module circuits, the ampacity of each of the module interconnection conductors shall not be less than the sum of the rating of the single fuse plus 125 percent of the short-circuit current from the other parallel- connected modules. 690.9 Over current Protection. 70