Surge protective devices (SPD) in the low-voltage main distribution (LVMD) of industrial plants, for example, are often installed and connected upstream of the circuit breaker. This fulfils the requirements of IEC 60364-5-53 to install SPDs as close as possible to the service entrance of the electrical installation. Planning engineers and switchgear manufacturers are frequently confronted with challenges such as lack of space in the switchgear cabinet, limited installation options and difficulty maintaining the maximum cable length of 0.5m stipulated in IEC 60364-5-53.

In addition, the issue of system availability is of paramount importance in many industrial companies. This also applies to the failure of SPDs. For this reason, defective surge protection must be replaced as quickly and safely as possible.

The new DEHNventil ACI M TNS 264 FM has the electrical and mechanical parameters to fulfil these requirements. DEHNventil ACI M TNS 264 FM does not require a backup fuse. The integrated ACI unit replaces and optimises the required overcurrent protective device. The low tripping integral is selective to a 35 A gG fuse; further overcurrent protective devices need not be considered. The integrated independent mechanical disconnection at the end of life ensures compliance with overvoltage category IV in accordance with IEC 60364-4-44 of 6 kV (at 230/400 V).

Thanks to the special design of the enclosure and contacting, protection against electric shock is ensured whatever the situation. The touch-safe design allows the protection module to be replaced without system downtime. This is a definite advantage when it comes to industrial plants. The protection module can be replaced flexibly from the side or front. Guides facilitate side and front insertion. Insulated tools are used for replacement.

Designed as a monobloc, the protection module is easy to replace. The integrated independent mechanical disconnection allows quick and easy replacement of the entire protection module when the fault indicator trips at the end of its service life.

The varying and often very confined space conditions when installing Type 1 arresters in industrial environments require flexible installation options. The various mechanical mounting options (DIN rail, mounting plate / switchgear cabinet wall and PE busbar via M8 screw) of the DEHNventil ACI M TNS 264 FM with simultaneous impulse current-tested contacting of the PE connection optimally fulfil this requirement.

Short-circuit current limiting spark gap ACI technology ensures very low clearing integrals both in normal operation and at the end of the arrester’s service life and enables connection of the DEHNventil M ACI with connection cross-sections of 16 mm² Cu, installed to be earth-fault and short-circuit-proof. This suffices for all short-circuit capacities at the installation location, provides planning certainty and saves installation time.