The proposed paper deals with the calculation of the excessive transmission line losses caused by the compact fluorescent lamps. The number of the installed compact fluorescent lamps is rapidly increased, nowadays. Since such a lamps have large impact on the power factor as well as on the voltage and current total harmonic distortion their inclusion to the low voltage electrical grid should be fully investigated. In the paper the numerical model, with nonlinear characteristics of compact fluorescent lamps inclusion, is dealt. The numerically analysis is performed for four different compact fluorescent lamps available on the Slovenian market.