insulator
(ˈɪnsjʊleɪtə(r))
[agent-n. in L. form, from insulate v.: see -or.]
One who or that which insulates; e.g. a body or substance that entirely or to a great degree prevents the passage of electricity or heat between contiguous bodies; a non-conductor; spec. a contrivance, usually made of glass or porcelain, for supporting or carrying telegraph or telephone wires, or power lines, without carrying off the current. Also used with reference to sound.
| 1801 Encycl. Brit. Suppl. I 605/1 Mr. Volta..and others..have attempted to shew how these substances are preferable..to more perfect insulators. 1814 G. J. Singer Elem. Electr. iii. iii. 278 Insulation may..be partially preserved by coating all the glass insulators with sealing wax. 1845 J. O. N. Rutter Hum. Electr. iii. 31 Glass is not the most perfect insulator (non-conductor); but in practice it is the most useful. 1847 Brett & Little Compendium Improvements Electr. Telegraphs 22 The insulators are made of earthenware, and secured direct to the poles. 1876 Preece & Sivewright Telegraphy 185 Seeing, however, that the insulators have little more than the weight of the wire to withstand, except at the terminal posts, no trouble is experienced in suiting the form of insulator to this. 1885 Watson & Burbury Math. Th. Electr. & Magn. I. 183 Non-conducting spaces may be occupied by actual substances, called non-conductors, insulators, or dielectrics..such as dry air and other gases, wood, &c. 1927 Davis & Kaye Acoustics of Buildings ix. 173 The usual principle is to have double walls..and to fill the space..with sound absorbents or insulators. 1950 Knudsen & Harris Acoustical Designing in Archit. xi. 246 If the porous blocks are not plastered, they may be very poor insulators: sound ‘leaks’ through the interstices. 1957 Encycl. Brit. XIV. 115I/1 On steel tower transmission lines the lightning voltage which can exist on the conductors..depends on the lightning flashover value of the supporting insulators. |
b. attrib. and Comb.
| 1876 Preece & Sivewright Telegraphy 159 Insulator breaking is the main evil which has been met with on roads. Ibid. 210 A small aperture..is previously cut in the middle; through this the insulator bolt and nut are placed. |