Surge Protection products from the PU1 series ( Class 1 ) , PU II series  ( Class II )  & PU III   ( Class III ) effectively reduce the surge protection even below the limits prescribed by the insulation coordination according to DIN VDE 0110. This means that the entire system is subjected to less interference.

The coordination is achieved by technical means. This means that decoupling between Classes I, II & III is not necessary.