This part of IEC 62735, which is a Technical Specification, applies to plugs and fixed socketoutlets for class I equipment with two active contacts plus an earthing contact, a rated power of 2,6 kW and a rated voltage range from 294 V to 400 V d.c. They are intended to power d.c. information and communication technology equipment only, products according to IEC 60950. The accessories according to this part of IEC 62735 are intended to be used by ordinary persons in data centres only where the value of the d.c. voltage distribution system is defined as follows: – 380 V with a tolerance of ±20 V for installations with no backup battery or with a voltage regulation system; – 380 V with a voltage range of 294 V to 400 V for installations with a backup battery where voltage regulation is not guaranteed; – the voltage value between each live conductor and earth does not exceed 200 V d.c. during normal operation; – there are two abnormal voltage ranges (duration below 10 min): • 260 V up to 294 V, and • above 400 V to 410 V. The maximum current of the plug and the socket-outlet is – 6,5 A when the voltage between live contacts is 400 V d.c., – 8,8 A when the voltage between live contacts is 294 V d.c. and can rise up to 10 A when the voltage between live contacts decreases to 260 V d.c. for 10 min maximum. The voltage between live conductors can fall down to 260 V d.c. when the voltage discharge value of the battery reaches the disconnecting level. The consequence is that the current increases accordingly. The accessories according to this part of IEC 62735 do not require maintenance. Plugs and socket-outlets covered by this part of IEC 62735 are intended for use in circuits where – basic protection, – an overcurrent protection (of 8,8 A or less for each socket-outlet or multiple socket-outlet), – the fault protection (indirect contact protection), and – additional protection are already assured. This part of IEC 62735 does not cover requirements for flush mounting boxes: however, it covers only those requirements for surface-type mounting boxes which are necessary for the tests on the socket-outlet. NOTE 1 General requirements for mounting boxes are given in IEC 60670. This part of IEC 62735 also applies to – plugs incorporated in cord sets, – plugs and socket-outlets incorporated in cord extension sets for data centres to be fixed to a wall or a rack, – the cord extension set and multiple socket-outlets for data centres intended to be fixed to a wall or a rack, and – socket-outlets which are a component of an assembly, unless otherwise stated in the standard for the relevant assembly. This part of IEC 62735 does not apply to – single or multiple portable socket-outlets not fixed to a wall or a rack; – plugs, socket-outlets and couplers for industrial purposes; – plugs, socket-outlets and vehicle couplers for electric vehicles according to the IEC 61851 and IEC 62196 series; – plugs and socket-outlets for household; – appliance couplers; – plugs, fixed and portable socket-outlets for extra-low voltage (ELV); NOTE 2 ELV values are specified in IEC 60364-4-41. – fixed socket-outlets combined with fuses, automatic switches, etc. Socket-outlets with pilot lights are allowed provided that pilot lights comply with the relevant standard, if any. Plugs and socket-outlets complying with this part of IEC 62735 are only suitable for use at ambient temperatures not normally exceeding +40 °C, but their average over a period of 24 h does not exceed +35 °C, with a lower limit of the ambient air temperature of −5 °C. Socket-outlets complying with this part of IEC 62735 are only suitable for incorporation or mounting in equipment in such a way and in such a place that it is unlikely that the surrounding temperature exceeds 35 °C.