Test methods and performance criteria for plug-in (portable) multiservice (multiport) surge protective devices (MSPDs) intended to protect equipment connected to one or more metallic conductive telecommunication line(s) and a 120 V/240 V single phase two-wire (line and neutral) ac power service, with the neutral grounded at the service equipment are defined in this standard. Performance testing covers three areas: the ac power SPD section, the telecommunication SPD section, and the MSPD as whole. Essential MSPD performance characteristics are the reduction of surge current in the equipment ground loops and surge coupling between the individual SPD sections.