DC String Combiner Box 2 Strings 600V 16A Isolators IP65

The QDC-SEZ DC field box protects and isolates two independent PV strings up to 600 V DC. Each string has its own load-break isolator, so one string can be opened under load while the other keeps running. The 600 V working voltage suits short strings or inverters with low-voltage MPPT inputs.

The isolator (SEZ): why a fuse is not enough

Direct current has no zero-crossing: once an arc is struck, it does not extinguish on its own. A fuse protects the conductor against overcurrent but must never be used as a switching device under load. The load-break isolator is built to open the DC circuit safely under load – for maintenance, fault-finding or emergency disconnection.

Note on the fuse: the 16 A rating refers to the nominal current per string; the box is fitted with a gPV 32 A / 1000 V fuse whose tripping curve is matched to the short-circuit current (Isc) of the modules.

When to choose this box

The 600 V configuration is the right choice when the cold open-circuit voltage (Voc) of the strings stays low – strings with few modules in series, or inverters and charge controllers whose MPPT range does not exceed 600 V. Always check the Voc at the minimum design temperature before sizing the string.

FAQ

Why 600 V and not 1000 V?

The 600 V ceiling suits short strings or inverters with low-voltage MPPT. If the cold Voc of your strings exceeds 600 V, choose the version rated up to 1000 V.

Can I isolate one string without interrupting the other?

Yes. Each string has its own isolator, so you can isolate one for maintenance while the other keeps producing.

Does installation require a qualified technician?

Yes. Installation and connection to the PV system must be carried out by a qualified installer, in compliance with the applicable standards (including CEI 0-21/0-16 and EN IEC 62548).