Cyclopedia of heating, plumbing and sanitation; a complete reference work . of conductors (double-braided) which may be installed in fibrous conduit. TABLE VIIISizes of Conductors in Fibrous Conduit OUTSIDE D AHETEB JlA METER One Wire in Tube 11 inch 11 inch No 12 2 1 ( 3 ti S fz \ << 6 H I a 1 1ft i it 2/0 l& l 250,000 C. M. 1A H 400,000 (. M. r. 750,000 CM. 21 11 1, C. M. 23 2 1,500,000 C M. • )-. — 8 -I 2,000,000 C. M. 305 1G ELECTRIC WIRING WIRES RUN EXPOSED ON INSULATORS This method o\ wiring has the advantages of cheapness,durability,and accessibility. Cheapness. Th
Cyclopedia of heating, plumbing and sanitation; a complete reference work . of conductors (double-braided) which may be installed in fibrous conduit. TABLE VIIISizes of Conductors in Fibrous Conduit OUTSIDE D AHETEB JlA METER One Wire in Tube 11 inch 11 inch No 12 2 1 ( 3 ti S fz \ << 6 H I a 1 1ft i it 2/0 l& l 250,000 C. M. 1A H 400,000 (. M. r. 750,000 CM. 21 11 1, C. M. 23 2 1,500,000 C M. • )-. — 8 -I 2,000,000 C. M. 305 1G ELECTRIC WIRING WIRES RUN EXPOSED ON INSULATORS This method o\ wiring has the advantages of cheapness,durability,and accessibility. Cheapness. The relative cosl of this method of wiring as com-pared with that of the concealed (-(111(11111 system, is about fifty per centof the latter if rubber-covered conductors are used, and about fortypercent of the latter if weatherproof slow-burning conductors are the Rules of the Fire Underwriters allow the use of weatherproofslow-burning conductors in dry places, considerable saving may beeffected by this method of wiring, provided there is no objection to it. Fig. 18. Large Feeders Run Exposed on Insulators. from the standpoint of appearance, and also provided that it is notliable to mechanical injury or disarrangement. Durability. It is a well-known fact that rubber insulation has arelatively short life. Inasmuch as in this method of w-iring, the insula-tion does not depend upon the insulation of the conductors, but onthe insulators themselves, which are of glass or porcelain, this systemis much more desirable than any of the other methods. Of course,if the conductors are mechanically injured, or the insulators broken,the insulation of the system is reduced; but there is no gradual dete-rioration as there is in the case of other methods of wiring, where 306 ELECTRIC WIRING 17 rubber is depended upon for insulation. This is especially true in hotplaces, particularly where the temperature is 120° F. or above. Forsuch cases, the weatherproof slow-burning conductors on p
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