Photovoltaic disconnect switch

A switch-disconnector for photovoltaic applications is a switching and isolating device specifically designed for the DC circuits of solar installations. It allows on-load closing and opening of PV strings and DC lines up to 2000 VDC depending on the range, with ratings from 25 A to 3200 A. The models comply with IEC 60947-3 with tests specific to photovoltaic DC constraints.

Photovoltaic switch-disconnector ranges and their fields of use

SIRCO PV and SIRCO MC PV for solar circuit isolation

The SIRCO PV range covers high-power installations with ratings from 100 to 3200 A and a voltage of up to 1500 VDC. Our installation feedback confirms its systematic use upstream of central inverters or grouped string inverters. The compact, factory pre-wired SIRCO MC PV is designed for string boxes, with ratings from 25 to 55 A up to 1000 VDC. We recommend the latter for its DIN-rail or rear-of-panel mounting, available in 1 to 2x3-pole versions to switch several strings simultaneously.

INOSYS LBS and the Telergon range for specific needs

INOSYS LBS extends DC isolation up to 2000 VDC, meeting new-generation high-voltage architectures. Our standard practice favours this range for large-scale solar projects with long distances between module fields and inverters. The Telergon entry-level range offers the F1 series up to 32 A at 1500 VDC with an IP66 rating, and the F7 series up to 55 A in 2- to 10-pole configurations with lockable handles. Feedback from installers confirms Telergon's appeal for budget-controlled projects that still require compliance with photovoltaic requirements.

Materials, mounting and adaptability to PV configurations

Mechanical construction and protection of solar DC disconnectors

Reinforced polyamide bodies resist mechanical and thermal stresses inside the panel. Pre-wired terminals on the MC PV versions significantly reduce on-site wiring time. IP65 and IP66 enclosures on the outdoor series, notably the Telergon F1 series, allow direct installation in harsh environments without an additional enclosure.

Connection versatility for photovoltaic circuits

In the field, we observe that installers make use of the mounting versatility of the available ranges: mid-point earthing, floating network, or bipolar configuration. This flexibility makes integration easier in architectures with or without a galvanic transformer. The compactness of the MC PV is a decisive advantage for optimising space in string-grouping boxes or solar inverter compartments.

Typical applications and operating points

Photovoltaic switch-disconnectors are mainly used for safety isolation of DC circuits upstream of inverters, emergency switching on solar installations, and grouping of PV strings in DC protection boxes. Our installation experience confirms that on-load making and breaking, tested beyond the requirements of IEC 60947-3, guarantee resistance to the specific constraints of photovoltaic DC current, whose arc is particularly difficult to extinguish.

Frequently asked questions

What is the difference between a PV switch-disconnector and a solar DC circuit breaker?

A photovoltaic switch-disconnector provides visible switching and isolation of DC circuits without overcurrent protection. The solar DC circuit breaker integrates this thermal-magnetic or single-pole protection function. We recommend combining them upstream of the inverter in line with the NF C 15-100 standard and the inverter manufacturer's instructions.

Can the SIRCO MC PV replace several single-pole disconnectors?

Yes, the 2x3-pole versions of the SIRCO MC PV allow several strings to be switched simultaneously with a single pre-wired device. Our installation feedback shows a saving in wiring time and reduced space in string-grouping boxes compared with assembling individual single-pole disconnectors.

Which range should be chosen for a 1500 VDC installation with an outdoor sealing constraint?

The F1 series of the Telergon range, with its IP66 enclosure and rating of up to 32 A at 1500 VDC, directly meets this need. For higher ratings up to 55 A, the F7 series remains available with lockable handles, although the protection rating should then be checked according to the exact model.

Is INOSYS LBS compatible with current 1500 VDC inverters?

Yes, and beyond: INOSYS LBS is rated up to 2000 VDC, anticipating the evolution of solar architectures toward higher DC voltages. We find that design offices are increasingly specifying it in tenders to future-proof large-power installations.