The item is used in connecting a light fitting or other device to the network supplying it. The counter coupling in the fitting is either NAC51.W or NAS51.W fitted in the device by the panel mounting adapter NK5P.W. The T-connector is fed with a NAC52S.W -coupler (or with an installation-ready cableset, where the NAC52S.W is coupled). The installation continues from the T-connector to the next device with a NAC51S.W (or with an installation-ready cableset, where the NAC51S.W is coupled).