Electrical conductive thermoplastic composites filled with carbon nanotubes (CNTs) have been widely researched during the last decade. One of the aims of current efforts is to reach high electrical conductivity at low filler content. Next to the properties of the polymer matrix, mainly the CNT characteristics, like type of CNT, its length or active surface area and chemistry, determine the electrical conductivity of polymer/CNT composites produced by melt mixing. In this contribution, three different types of CNTs were incorporated in polypropylene (PP), polycarbonate (PC) and polyvinylidenefluoride (PVDF) using a conical twin screw microcompounder Xplore DSM15 and compression molded plates were prepared. The commercial CNTs were singlewalled CNT Tuball® from OCSiAl Ltd. (Russia), multiwalled CNT NC7000 from Nanocyl, S.A. (Belgium) as well as branched and entangled MWCNTs having surface modification of polyethylene glycol (CNS-PEG) from Applied NanoStructured Solutions (USA). The composites were characterized concerning their electrical and thermal properties and filler dispersion. The electrical percolation thresholds for composites of PP/Tuball, PP/CNS-PEG and PC/CNS-PEG were found already at 0.1 wt%. For PVDF/Tuball, PVDF/CNS-PEG and PC/Tuball percolation starts between 0.1 and 0.25 wt%. At 2 wt% filler all composites with CNS-PEG show lower volume resistivity values than the other fillers. Values of about 3 Ohm·cm were achieved in PVDF, 7 Ohm·cm in PP and 11 Ohm·cm in PC based composites. The highest percolation thresholds were always measured for composites with NC7000. The main reason for this may be the significantly lower aspect ratio of NC7000 compared to the other kinds of CNT. A homogeneous dispersion was observed especially for composites containing CNS-PEG. For all CNTs a nucleation effect was found in differential scanning calorimetry. At the same CNT content the highest values of crystallisation temperature were found for CNS-PEG and Tuball.