What to Confirm When Sourcing DC PV Fuse Holders

A photovoltaic string fuse is there to isolate a faulted string, not to carry the array. The holder has to interrupt DC, sit in the right enclosure, and match the fuse link the module maker allows.

Use a DC holder, not an AC cartridge from the lighting board

10×38 mm holders look similar across AC and DC catalogues. For a string, the holder and the gPV link both need a DC voltage rating that covers the string open-circuit voltage at the lowest expected temperature. An AC-only holder can fail to clear a DC arc.

Size the link from the module, then check the holder

Start from the module short-circuit current and the multiplier in the local code, then pick a gPV link at or below the module maximum series fuse rating. The holder current rating has to be at least that of the link, and the DIN-rail footprint has to fit beside the surge device and the isolator already in the combiner.

What to send with the enquiry

String voltage, maximum series fuse rating, indoor or outdoor enclosure, and whether the holder needs a pull-out carrier for isolation. Pronto can then coordinate a 10×38 mm DC holder, such as the KNRT-32M class, with the fuse link and the box it has to live in.