Should EMC interferences such as lightning strikes occur,
the spark gap ignites and discharges the interference pulse without consequential
damage to equipment. This reduces the residual impulse on the active lines and
the terminal devices are subject to even less stress. The BLITZDUCTOR CT
arrester is equipped with a patented insert that can take a gas discharge tube, if
necessary. This switches between the cable shield and the local earth. The gas discharge
tube can be inserted or removed during upgrading or maintenance work in
order to change between direct and indirect shield earthing (Figure 7.20)..