Low-voltage electrical installations – Part 5-56: Selection and erection of electrical equipment – Safety services
|Publication Date:||1 July 2009|
|ICS Code (Installations in buildings):||91.140|
For safety services required to operate in fire conditions, the following two conditions shall be fulfilled:
- a safety source of supply shall be selected which will maintain a supply of adequate duration, and
- all equipment shall be provided, either by construction or by erection, with protection ensuring fire resistance of adequate duration.
- the safety source is generally additional to the normal source.
NOTE - The normal source is, for example, the public supply network.
Protective measures against electric shock in case of a fault without automatic disconnection at the first fault are preferred. In IT systems, continuous insulation monitoring devices shall be provided which give an audible and visible indication of a first fault.
Equipment shall be arranged to facilitate periodic inspection, testing and maintenance.