Scope and object This Technical Specification sets out design requirements for photovoltaic (PV) arrays including d.c. array wiring@ electrical protection devices@ switching and earthing provisions. The scope includes all parts of the PV array up to but not including energy storage devices@ power conversion equipment or loads. The object of this Technical Specification is to address the design safety requirements arising from the particular characteristics of photovoltaic systems. Direct current systems@ and PV arrays in particular@ pose some hazards in addition to those derived from conventional a.c. power systems@ including the ability to produce and sustain electrical arcs with currents that are not greater than normal operating currents. In grid connected systems the safety requirements of this Technical Specification are however critically dependent on the inverters associated with PV arrays complying with the requirements of IEC 62109-1 and IEC 62109-2. Installation requirements are also critically dependent on compliance with IEC 60364 series (see Clause 4). PV arrays of less than 100 W and less than 35 V d.c. open circuit voltage at STC are not covered by this Technical Specification. Attention is drawn to Annex D describing arc fault detection and interruption in PV arrays. It is expected that requirements for the use of this type of equipment will be included in this Technical Specification when reliable commercial equipment for detection of arcs in PV systems is available. NOTE 1 This Technical Specification covers the protection requirements of PV arrays which develop as a result of the use of batteries in PV systems. NOTE 2 Additional requirements may be needed for more specialized installations e.g. concentrating systems@ tracking systems or building integrated PV.