Madalpingelised elektripaigaldised. Osa 4-444, Kaitseviisid. Kaitse pingehäiringute ja elektromagnetiliste häiringute eest = Low-voltage electrical installations. Part 4-444, Protection for safety. Protection against voltage disturbances and electromagnetic disturbances (IEC 60364-4-44:2007 (Clause 444), modified)