DC String Combiner Box 4 Strings 1000V 16A Isolators and SPD IP65
IP65 DC field box for 4 strings at 1000 V, 16 A per string. Full protection on every string – isolator, gPV 32 A fuse and SPD surge arrester – in a 36-module DIN box.
The QDC-04/04 DC field box combines and protects four PV strings up to 1000 V DC, with 4 inputs and 4 outputs. Each string carries three levels of protection: isolator, fuse and surge arrester (SPD). It is the choice for medium-sized arrays where several strings are gathered at a single collection point.
Three protections on every string
The isolator opens the DC circuit safely under load, for maintenance or emergency – essential because direct current has no zero-crossing and an arc does not extinguish on its own. The fuse protects the conductor against overcurrent. The SPD surge arrester diverts to earth the surges induced by indirect lightning, protecting modules and inverter.
| Strings | 4 (4 IN / 4 OUT) |
| Max voltage | 1000 V DC |
| Current per string | 16 A |
| Protection per string | isolator + 32 A 1000 V fuse + SPD |
| Enclosure | IP65, 36 DIN modules |
| Weight | 3 kg |
Note on the fuse: the 16 A rating refers to the nominal current per string; the box is fitted with fuse holders and gPV 32 A / 1000 V fuses whose tripping curve is matched to the short-circuit current (Isc) of the modules.
When to choose this box
The 4-string configuration suits systems where several strings must be collected and individually protected before the inverter or the next board. The SPD makes it well suited to sites more exposed to lightning risk. Check that the cold Voc of each string does not exceed 1000 V.
FAQ
What is the difference between isolator, fuse and surge arrester?
They have distinct, complementary roles: the fuse acts on overcurrent, the isolator allows manual disconnection under load, the SPD protects against surges. Together they form the complete DC protection of the string.
Do I need an SPD even on a small system?
An SPD is more valuable the more exposed the system is (lightning-prone areas, rooftop or ground arrays). It protects the most expensive parts of the plant – modules and inverter – from transient surges.
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).