Description
for solar (PV) systems you need DC‑rated over current protection (breakers or fuses), sized and placed according to PV codes. Here’s the quick guide:Use DC‑rated/PV‑listed breakers (e.g., UL 489B) — not ordinary AC breakers. DC arcs don’t have a natural zero‑crossing, so AC breakers may fail to interrupt safely. UL 489B covers molded‑case breakers for PV up to 1500 V DC.
Where to put them (typical DC side):Each string (in a combiner) when multiple strings are paralleled.Between the array/combiner and the inverter or charge controller.
Battery circuits (if present) also need appropriately rated DC OCPD. (Article 690/706 cover PV + storage.)
