Madalpingelised elektripaigaldised. Osa 5-53, Elektriseadmete valik ja paigaldamine. Lülitus- ja juhtimisaparaadid. Jaotis 537, Turvalahutamine ja lülitamine [Võrguteavik] = Low-voltage electrical installations. Part 5-53, Selection and erection of electrical equipment. Devices for protection, isolation, switching, control and monitoring. Clause 537, Isolation and switching