Surge protection always safely dimensioned

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 avoid possible configuration errors made when selecting and dimensioning a suitable backup fuse.

Your advantages with the complete ACI unit

Safe dimensioning: prevent mistakes

The switch-spark gap combination ACI is integrated directly in and perfectly adjusted to the arrester. No time and effort needs to be spent on selecting the right fuse size and tripping characteristics. Correct dimensioning of the conductor cross-section and observance of selectivity to upstream fuses is always ensured.

This is the way to prevent dimensioning errors and increase the availability of your system.

Smaller connection cross-section: easier to install

You save the valuable time you would, in the past, have spent dimensioning the cross-sections. You no longer need conductors with different cross-sections.

6 mm² also makes installation easier because the radiuses are smaller and the wiring shorter.

2 aspects which save you money and make your daily work easier.

TOV withstand: increase availability

Temporary overvoltages can damage conventional surge protective devices. The new ACI arresters have a much better TOV withstand.

This reduces the risk for your system and avoids wasting time and money on repairing unnecessary damage.

Zero leakage current: increase the service lifetime

With an ACI arrester there are no leakage currents which might lead to premature ageing, even in networks with voltage fluctuations. You thus avoid spending money and time on replacing arresters ahead of schedule.

By the way, ACI arresters also contribute towards operational safety because they prevent the accidental tripping of the insulation monitoring. The protection module does not have to be removed for insulation measurements up to 500 V.

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 flowing through the varistor is interrupted. This is down to the switch-spark gap combination connected in series. The fault current is 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.


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

You would like to know more about ACI technology? Get in contact with the support team.

Product details DEHNguard ACI

Nominal voltage AC (UN)230/400 V
Maximum voltage (UC)275 V
Nominal discharge current (In)20 kA
Short circuit withstand current AC (ISCCR)25 kA
Additional external backup fuse-
Voltage protection level (UP)< 1,5 kV
TOV withstand min.440 V
Configurations3+1, 4+0, 3+0, 2+0, 1+1
Temperature range-40 ... + 80°C