... :1.CCC,CE appliant;2.Products overview:GBL series surge protector is applicable to TT,IT,TN-S,TN-C- ... ,GB50057-94(2000 VERSION);3.Scope of application:GBL series surge protector is applicable to TT,IT,TN-S,TN-C ... up to 400V and protects grid for lightning strike and surge over-voltage.