An assembly can include a housing that includes opposing ends, a longitudinal axis, an axial length defined between the opposing ends, a maximum transverse dimension that is less than the length and an interior space; circuitry disposed at least in part in the interior space; and a coated electrical conductor electrically coupled to the circuitry where the coated electrical conductor includes an electrical conductor that includes copper and a length defined by opposing ends, a polymeric electrical insulation layer disposed about at least a portion of the length of the electrical conductor, and a barrier layer disposed about at least a portion of the polymeric electrical insulation layer.