Fuse disconnect switch

The fuse-combination switch-disconnector is a modular device that combines three electrical functions in a single enclosure: on-load switching, visible circuit isolation, and short-circuit protection by fuses. The FUSERBLOC and FUSOMAT ranges cover ratings from a few amps up to 1250 A, with AC-22 and AC-23 utilisation categories compliant with IEC 60947-3. Double break per phase and fully visible break ensure operator safety during maintenance work.

Functions and principle of the fused switch-disconnector

On-load switching and isolation in a single device

The fuse-combination switch-disconnector performs both on-load circuit switching and the visible isolation required by the NF C 15-100 standard for personal safety. Our installation experience confirms that this functional integration removes the need to juxtapose a separate disconnector and circuit breaker, significantly reducing panel space. Double break per phase provides enhanced isolation between open contacts, while the fully visible break lets the operator visually check the device's status without dismantling.

Fuse protection and high breaking capacity

The built-in fuse carriers accept multiple fuse formats: 10x38 mm, 14x51 mm and 22x58 mm cartridges, as well as NF/DIN formats and industrial sizes from 00C to 3. This versatility allows the breaking capacity to be adapted to each installation's specific requirements, up to 100 kA for demanding industrial applications. Feedback from installers confirms that replacing fuses on low-voltage installations remains a fast, standardised operation thanks to silver-plated copper fuse carriers.

FUSERBLOC and FUSOMAT ranges: ratings and configurations

FUSERBLOC: the extended range up to 1250 A

The FUSERBLOC range covers a particularly wide rating span, up to 1250 A, with front or front-side control configurations depending on panel accessibility constraints. Our standard practice favours front-side control when panel depth is critical, as it allows the operating shaft to be offset without adding complex accessories. Mounting is on DIN rail, plate or modular panel depending on the architecture chosen for the electrical panel equipment.

FUSOMAT: sizes T2 to T4 for applications up to 800 A and beyond

The FUSOMAT range comes in sizes T2, T3 and T4, covering applications up to 800 A and beyond for certain configurations. In the field, we find that these standardised sizes make it easier to select replacement fuses and to harmonise maintenance stock. Dimensional consistency between the different sizes also allows power upgrades to be anticipated during installation extensions.

Materials, finishes and accessory compatibility

Mechanical construction and resistance in industrial environments

The device body is made of reinforced polyamide, offering resistance to mechanical impacts and to operating temperatures inside the electrical panel. Operating handles, available in black or red polycarbonate, provide immediate visual identification of function: red generally signals emergency-stop or main isolation functions. Our commissioning tests show that this colour coding reduces operating errors during lock-out procedures.

Accessories common with the SIDERMAT range

The wide range of accessories shared with SIDERMAT is a major asset for maintenance and installation standardisation. Handles, extension shafts and position auxiliary contacts are interchangeable between the two ranges, simplifying spare-parts management and reducing intervention times. Our installation feedback shows that this compatibility is particularly appreciated in industries deploying both fused switch-disconnectors and motor circuit breakers on the same site.

Typical applications and installation integration

Protection of motor outgoing circuits and distribution circuits

The fuse-combination switch-disconnector is mainly used for combined protection and isolation of motor outgoing circuits and industrial distribution circuits. Coordination between the switching function and fuse characteristics helps to manage short-circuit energies in high short-circuit-power networks. We recommend this solution when the required breaking capacity exceeds that of standard circuit breakers, or when selectivity with the upstream network requires controlled melting times.

Installation contexts and regulatory constraints

Utilisation categories AC-22 (switching mixed light resistive and inductive loads) and AC-23 (switching motors or heavily inductive loads) cover most applications found in industrial low-voltage distribution. Compliance with the IEC 60947-3 standard guarantees suitability for switching and isolation under the conditions defined by this standard in the IEC 60947 series. For installations subject to specific regulations, the availability of standardised NF fuse formats makes it easier to demonstrate compliance.

Frequently asked questions

What is the difference between FUSERBLOC and FUSOMAT in the fuse-combination switch-disconnector range?

FUSERBLOC is the broadest range, covering ratings up to 1250 A with a wide variety of fuse sizes and mounting configurations. FUSOMAT focuses on sizes T2 to T4 for applications up to 800 A and beyond, with standardisation favouring maintenance. The choice between the two ranges depends on the required rating and the site's equipment-harmonisation policy.

Can a fuse-combination switch-disconnector be used to isolate a motor outgoing circuit in compliance with NF C 15-100?

Yes, the fully visible break and double break per phase meet the visible isolation requirements of NF C 15-100 for personal safety. Utilisation category AC-23 explicitly permits motor switching, making the device suitable for industrial motor outgoing circuits. We find that this solution is frequently chosen when the network's short-circuit capacity exceeds 50 kA.

Which fuse formats are compatible with the fuse carriers of the FUSERBLOC and FUSOMAT ranges?

The fuse carriers accept 10x38 mm, 14x51 mm and 22x58 mm cartridges for modular applications, as well as NF/DIN formats and industrial sizes from 00C to 3 for high ratings. This diversity allows the breaking capacity and rated current to be adapted to each distribution or motor outgoing circuit, by selecting fuses according to the appropriate melting curves.

Are SIDERMAT accessories directly interchangeable with FUSERBLOC and FUSOMAT fused switch-disconnectors?

Handles, extension shafts and position auxiliary contacts are common to the SIDERMAT, FUSERBLOC and FUSOMAT ranges, ensuring direct interchangeability without mechanical adaptation. This standardisation reduces stock references and speeds up maintenance work, particularly in industries deploying all three ranges across the same equipment fleet.

Which mounting type should be preferred for a fuse-combination switch-disconnector in a new electrical panel?

DIN-rail mounting offers the greatest flexibility for future reorganisation and switchboard extensions. Plate or modular panel mounting suits fixed configurations where compactness is optimised. Our installation experience confirms that the choice mainly depends on maintenance policy and the likelihood of future changes to the installation.