IEC 60364-5-56:2009 covers general requirements for safety services, selection and erection of electrical supply systems for safety services and electrical safety sources. Standby electrical supply systems are outside the scope of this part. This part does not apply to installations in hazardous areas (BE3), for which requirements are given in IEC 60079-14. This second edition of IEC 60364-5-56 comes about as a result of changes to Clause 556, Safety services, of IEC 60364-5-55 (2001), as modified by its amendment 1 (2001). It replaces Clause 556 of IEC 60364-5-55:2001. Clause 556 is to be withdrawn at the time of publication of this new Part 56. The main changes with regard to the previous edition are listed below: 1) Many more definitions are included, e.g. response time, central power supply system, low power supply system, preferential circuit and escape route. 2) Automatic supplies are now classified according to the maximum changeover times, for example a supply classified as short break means an automatic supply is available within 0,5 s. 3) Safety sources that can operate in parallel are specifically recognized in 560.6.9. 4) Requirements are now given for batteries used for safety sources for central and low power supply sources. 5) Drawings are now required, such as a single-line diagram, drawings showing the location of equipment and a list of equipment permanently connected to the safety power supply. 6) Operating instructions are now required. 7) Detailed requirements are now given for emergency escape lighting applications, direct current circuits and fire protection applications. 8) Additional requirements for initial verification and periodic inspection and testing are now included in the standard. 9) Two annexes are now included (Annex A and Annex B) giving guidance for emergency lighting and guidance for fire protection equipment, respectively.