A polymer composition for use in an electric circuit protection device is provided. The polymer composition comprises a polymer matrix that includes a thermotropic liquid crystalline polymer. The polymer composition exhibits an in-plane thermal conductivity of about 3.5 W/m-K or more as determined in accordance with ASTM E1461-13 and a melt viscosity of from about 1 to about 100 Pa-s as determined in accordance with ISO Test No. 11443:2014 at a temperature 15° C. higher than the melting temperature.