Solarcell trainer1/9/2023 ![]() This includes controlled conductors located inside the boundary or up to three feet from the point where they penetrate the surface of the building.Īs of 2019, the NEC made these requirements more stringent by requiring: According to section 690.2 of that code, PV array boundary is a mechanically integrated assembly of modules or panels with a support structure and foundation, tracker, and other components, that form a DC or AC producing unit. The 2017 National Electrical Code (NEC), Section 690.12 requires the “rapid shutdown” of PV systems both inside and outside the PV array boundary. To reduce shock hazard for technicians and first responders, we need a way to shut those strings off during a short circuit or power outage. Control measures: Rapid shutdown systemsĮnergy produced from PV string systems varies directly with the sun. The grounding conductor bonds all metallic components together-and eventually to ground-through the grounding electrode conductor and grounding electrode. Key places to look for these conditions in a PV system include the combiner box, PV source and output circuit conductors, and the equipment grounding conductor. That’s more than 2.5 times the lethal limit of 75 mA, so protecting yourself and your workers against such an event is critical.Įlectrical shocks are typically caused by a short circuit resulting from corroded cables and connections, loose wiring, and improper grounding. To calculate the amount of current that would course through a person’s body if exposed to 120 V, simply divide 120 V by 600 ohms (I = V/R), which totals 0.2 amps or 200 mA. Per Ohm’s law, voltage (V) equals current (I) times resistance (R), so V = IR. The human body has a resistance of about 600 ohms. Current as low as 75 milliamps (mA) across the heart is lethal. Just as with other electric power generation, PV systems present the risk of shock and electrocution when current takes an unintended path through a human body. Shock or electrocution from energized conductors These are three of the most common electrical hazards with PV systems that you can enounter, along with specific solar PV safety control measures you can take to reduce their risk.
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