This standard specifies the minimum requirements for installation of Power over Ethernet (PoE) lighting systems to ensure minimal energy losses. A typical PoE lighting system uses standardized ethernet twisted pair cable (e.g. category 5e cable) to connect powered devices (PDs)@ such as luminaires@ to DC power source equipment (PSE) (e.g.@ network switch) without the need for AC line voltage power to the luminaires. The ethernet cable also carries data for control and monitoring of the luminaire. The energy efficiency of a PoE lighting system depends on three elements: PSE efficiency@ PD efficiency@ and cable energy losses. This standard specifies cable and installation practices to limit the electrical energy losses of the cable between the PSE and the PD. Applications include@ but are not limited to@ commercial@ residential@ and industrial lighting applications.