Insulator
Insulators Edit Watch this page Read in another language Insulator (electricity) This article is about electrical insulation. For insulation of heat, see Thermal insulation . Ceramic insulator used on electrified railways 3-core copper wire power cable, each core with individual colour-coded insulating sheaths all contained within an outer protective sheath PVC-sheathed mineral insulated copper cable with 2 conducting cores An electrical insulator is a material whose internal electric charges do not flow freely; very little electric current will flow through it under the influence of an electric field . This contrasts with other materials, semiconductors and conductors , which conduct electric current more easily. The property that distinguishes an insulator is its resistivity ; insulators have higher resistivity than semiconductors or conductors. A perfect insulator does not exist, because even insulators contain small num