This standard applies to two up to five wire installation couplers including earth@ if provided@ with a rated voltage up to and including 500 V a.c. and a rated connecting capacity up to and including 10 mm? for permanent connection in indoor electrical installations. Installation couplers with additional contacts for voltages other than mains voltages are outside the scope of this standard. NOTE 1 Installation couplers according to this standard are used e.g. in prefabricated buildings@ installation cavities@ such as suspended floors and ceilings@ or cable tray systems@ cable ladder systems@ cable ducting systems and cable trunking systems or in commercial show rooms@ in partition walls and in any similar application or in furniture complying with IEC 60364-7-713. NOTE 2 This standard may be used as a guide for installation couplers with additional contacts for voltages other than mains voltages. NOTE 3 In the UK@ where installation couplers have more than 5 wires@ they shall meet the requirements of IEC 61535 as though they were included in the scope and shall be tested in such a way that all of the mains voltage pins are subjected to the same level of testing. NOTE 4 In the USA@ these installation couplers are not permitted to be used where they will not be visible after installation. An installation coupler consists of an installation female connector and an installation male connector for permanent connection not intended to be engaged or disengaged under load nor to be engaged or disengaged other than during first installation or during reconfiguration or maintenance of the wiring system in which installation couplers have been installed. This means that installation couplers are only intended for infrequent use. Installation couplers are not suitable for use in place of socket-outlet systems. Installation couplers are not suitable for use in place of devices for connecting luminaires (DCLs) according to IEC 61995 or luminaire supporting couplers (LSCs). NOTE 5 For lower limits of in-service temperatures the necessary information is given in the manufacturer's installation instructions. In locations where special conditions prevail@ as in ships@ vehicles and the like and in hazardous locations@ for example where explosions are liable to occur@ special constructions may be required. NOTE 6 Particular requirements for installation couplers e.g. for. use at higher ambient temperatures@ with higher mechanical durability (e.g. metal housings)@ with higher fire resistance and for use in control circuits (e.g. SELV)@ are under consideration. NOTE 7 National rules may have requirements concerning the accessibility of installation couplers. NOTE 8 Installation couplers are intended to be installed by instructed or skilled persons. NOTE 9 National rules may specify who is allowed to carry out the connection and disconnection of installation couplers.