Elementary telegraphy : a manual for students; written specially to meet the requirements of the ordinary grade of the subject as published in the syllabus of the city and guilds of London Institute (1910)
Pendry, H. W. (Henry Walter) · London ; New York : Whittaker & Co. · leaf 214
circnits is pro-vided for as re.gards aerial lines by the i*egnlation thatcpiard irires must be erected and maintained at placeswhere there is a liability of contact with snch overheadconduct(n-s. The risk of damage to apparatus, shock tooperators, or even a fire has been safeguarded by the… … PROTECTORS Frc. 173.—Arraiigiineut of hiat coil ami piotector for twoliiK.s and iiistruiiifiits. a coml)ination of these are supplied in fire-proof cases,but in larger stations they are fitted on a test and cross-connection frame in a basement fire-proof chand:)er toAvhich also the underground…
Telegraph
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