Ques. State the disadvantages.
Ans. The covering is more or less inflammable and is not very efficient as an insulator.
Ques. What precaution should be taken in using weather proof conductors?
Ans. On account of the inflammable character of the covering, care should be taken in wiring at points where any considerable number of conductors are brought together, or where there is much woodwork or other combustible material.
Ques. For what use are weather proof conductors especially adapted?
Ans. For outside wiring where moisture is certain and where fireproof quality is not necessary.
Obviously conductors of this class should not be used in conduits, nor in fact, in any way except exposed on glass or porcelain insulators.
Slow Burning Wire.—This class of conductor is defined as: one that will not carry fire. The covering consists of layers of cotton or other thread, all the interstices of which are filled with the fireproofing compound, or of material having equivalent fire resisting and insulating properties. The outer layer is braided and specially designed to withstand abrasion. The thickness of insulation must not be less than that required for slow burning weather proof wire and the outer surface must be finished smooth and hard.—Underwriters' requirements.
