# Short-Circuit Current (Isc)

The current a solar module or string delivers when its terminals are shorted together, which is the maximum current it can produce. It scales almost directly with irradiance and changes only slightly with temperature.

Source: https://inverterdata.com/en/glossary/short-circuit-current/
Site: InverterData (inverterdata.com) — open technical specification database
Last updated: 2026-08-24
License: free to quote with attribution to inverterdata.com

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Isc governs conductor sizing, fuse ratings, combiner design and how many strings may be paralleled on one **MPPT channel**. Wiring and protective devices are rated above Isc with a deliberate margin — in the United States the National Electrical Code applies a 125% factor, partly to allow for brief irradiance enhancement when sunlight reflects off cloud edges. Because a shorted PV string is a current source rather than a voltage source, it does not blow a fuse the way a battery short would: it quietly delivers roughly its normal current, which is precisely what makes DC arc faults in PV systems so persistent.