A flat electrical cable is described. The cable includes a plurality of equally spaced substantially parallel electrical conductors lying in a same plane and extending along the length of the cable. Each conductor has a same diameter D. The cable further includes a common unitary electrically insulating layer encapsulating the plurality of conductors. The insulating layer includes a plurality of cover portions where each cover portion is concentric with a corresponding conductor and has a radial thickness t. t/D is in a range from about 0.50 to about 1.25.