Array boundary

The array boundary is a term from the NEC rapid shutdown rules: the zone extending 305 mm (1 ft) from the PV array in all directions. Where a controlled conductor sits relative to this boundary decides which rapid shutdown limit applies to it: 690.12(B)(1) outside, 690.12(B)(2) inside. Outside the boundary, or more than 1 m (3 ft) past the point of entry into a building, controlled conductors must drop to 30 volts or less within 30 seconds of rapid shutdown initiation. Voltage is measured between any two conductors and between any conductor and ground. Inside the boundary, the system can use a listed or field-labeled rapid shutdown PV array. Otherwise, controlled conductors must drop to 80 volts or less within 30 seconds. In one manufacturer's commercial guide, the inverter DC input circuits stay inside the array boundary. The AC output circuits run outside it and meet the outside-boundary limit once the AC breaker or AC disconnect is opened. Ways to comply include module-level power electronics or a UL 3741 listed array, and sub-arrays can be kept within the same array boundary. The purpose of rapid shutdown is to reduce shock hazard for emergency responders working on buildings with PV.

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• sentence 4: support check: partial - The listed or field-labeled rapid shutdown array option and the 80 V in 30 s option are stated, but the statement omits the third exemption, and the 80 V limit is tied to the boundary or 1 m from the penetration point.
• sentence 4: review: partial - The listed or field-labeled rapid shutdown array option and the 80 V within 30 s limit are both stated, but 'otherwise' leaves out the third option (the exemption for arrays with no exposed wiring or conductive parts) and leaves out… -->