Thermoplastic compositions include: (a) a thermoplastic polymer including a polycarbonate component; (b) a poly(carbonate-siloxane) copolymer; and (c) from 4 wt % to 25 wt % carbon black. The composition has a total siloxane content of from 2 wt % to 14 wt %. The thermoplastic compositions exhibit improved physical properties as compared to compositions that do not include the poly(carbonate-siloxane) copolymer, including volume resistivity, melt viscosity, impact strength, puncture impact energy and surface resistivity.