At this point it should be
expressly emphasized that this voltage only provides insulating resistance between input and output (CM interference). This means that, when installed in transmission systems, attention must be paid not only to the limitation of CM interferences but also to sufficient limitation of DM interferences. Furthermore, the integration of supplementary decoupling resistors at the output of the SPD enables energy coordination with the optocoupler diode. Hence, in this case, CM and DM interference limiting SPDs, such as the BLITZDUCTOR XT BXT ML BE C24 (www.dehn.de), must be installed.