ACI device safety
ACI: The highest level of safety

Equipped for the future: Surge protection with ACI technology

The new ACI Technology Advanced Circuit Interruption – improves the safety of your electrical systems.

New: The switch / spark gap combination in type 2 arrester DEHNguard ACI makes upstream fuses superfluous. As a backup fuse is no longer required, you save time, space and material.

A further bonus: you eliminate possible configuration errors made when selecting and dimensioning a suitable backup fuse.

Reduce expenses and make your system safe!

Your advantages with the complete ACI unit

Safe dimensioning: eliminate mistakes

With ACI arresters you can eliminate those configuration errors previously made when selecting and dimensioning a backup fuse. This increases the availability of your system. The new switch / spark-gap combination is integrated directly in and perfectly adjusted to the arrester. So no more time and effort needs to be spent on finding the right fuse size and selectivity.


TOV withstand: increase availability

Temporary overvoltages (e.g., due to loss of neutral) can destroy conventional surge protective devices. The new ACI arresters have a much better TOV withstand. This increases the availability of your system and avoids wasting time and money on repairs.

Connection cross-section of just 6 mm²: easier to install

A connection cross-section of just 6 mm² Cu is always enough. You save the valuable time you would, in the past, have spent on dimensioning the cross-sections.
Only 6 mm² Cu also means simpler installation because the radiuses are smaller and the wiring shorter.

Zero leakage current: increase arrester lifetime

The technology in an ACI arrester means that there are no leakage currents. This prevents premature ageing of the protective devices and saves the time and expense of replacing arresters ahead of schedule.
ACI arresters also prevent the accidental tripping of the insulation monitoring and contribute towards operational safety. 

Future energy structure: fulfil requirements

The global power supply is in a period of transition. Renewable power generation is creating new grid parameters. Isolated grids and storage systems are changing the short-circuiting conditions. With ACI technology you are well-equipped for these future requirements.


For highest possible availability – to keep your system up and running

The switch / spark gap combination in DEHNguard ACI is connected in series with a varistor. At the end of the service life of the ACI surge arrester, any fault current is interrupted by the varistor through the switch / spark gap combination connected in series and reduced to such an extent that not even the smallest fuses in the system are tripped.

This means much greater availability and operational safety for the system in comparison with standard type 2 arresters with external fuses.

Standard solution CI technology ACI technololgy
Safe dimensioning - -
Smaller connection cross-section - only 6mm2 - -
Longer service life due to TOV withstand and zero leakage current - -
Monitoring overcurrent protection -
More space in the switchgear cabinet -
No external backup fuse needed -
Thermo Dynamic Control
Protective effect of a type 2 arrester

Product details DEHNguard ACI

  • Nominal voltage AC (UN): 230/400 V
  • Maximum continuous operating voltage (UC): 275 V
  • Nominal discharge current (IN): 20 kA
  • Short circuit strength AC (ISCCR): 25 kA
  • Additional external backup fuse: -
  • Voltage protection level (UP): < 1,5 kV
  • TOV withstand: min. 440 V
  • Configuration: 3+1, 4+0, 3+0, 2+0, 1+1
  • Temperature range: -40 ... + 80°C
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