String polarity measurement

A string polarity measurement uses a multimeter or voltmeter to confirm that the positive and negative conductors of each PV string are wired the right way round. Connect the meter's positive lead to the string's positive cable and its negative lead to the negative cable. A negative reading on the display means the string is connected in reverse polarity. Measure each string on its own, before it is connected to other strings or the inverter. Do the check before any other tests and before switches are closed or string fuses are inserted. When a CPS inverter reports a PVxReverse fault, turn the DC switch off and open the fuse holders to isolate the strings. Then use the meter to find the reversed string and correct its wiring. An open-circuit voltage well below the expected value can also point to modules wired with the wrong polarity inside a string. The inverter does not protect against a reversed string. It is very dangerous: under strong sunlight it can blow a fuse and start a fire. If you find a reversed string on a system that was already connected, check its modules and bypass diodes for damage. Record the result for each string on the test report sheet.

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• sentence 6: support check: partial - Passage says reversed string is not protected by inverter, hazardous, blows fuse at high irradiation, and could result in fire, but 'strong sunlight' and fire are conditional (fuse may fail to operate), roughly matching though simplified.
• sentence 8: support check: partial - The report sheet has a polarity check row per string, implying recording, but no passage explicitly instructs recording results per string. -->