This European Standard applies to phase couplers in a mains communication system for phase to neutral voltage not exceeding 250 V a.c. and a nominal current not exceeding 125 A, intended for household and similar fixed installation including residential, commercial and light industrial buildings. This European Standard applies to phase couplers used to control the coupling of communication signals between phases or sections of a mains communication system. A "phase coupler" may be used to achieve coupling between the phases of a multiphase installation, or to provide bridging of signals around other system components.