This Acti9 iPRD8 surge arrester protects 3P+N installations. It allows quick replacement of damaged cartridges. The Imax maximum discharge current is 8kA .The In nominal discharge current is 2.5kA. The iPRD8r ensures secondary protection of loads to be protected and is placed in cascade with the incoming surge arresters. This surge arrester is required when the loads to be protected are at a distance of more than 10 m from the incoming surge arrester. The Uc maximum continuous operating voltage in common mode is 260VAC between neutral and earth