Modern electrical construction; a reliable, practical guide for the beginner in electrical construction, showing the latest approved methods of installing work of all kinds according to the safety rules of the National board of fire underwriters (1905)
Horstmann, Henry C[harles], 1858- [from old catalog], Tousley, Victor Hugo, 1875- [from old catalog] joint author · Chicago, F. J. Drake & Co. · leaf 195
/. Base.—Current-carrying parts must be mounted on non-combustible, non-absorptive insulating bases, such as slate orporcelain, and the holes for supporting screws should be coun-tersunk not less than one-eighth of an inch. There must 192 MODERN ELECTRICAL CONSTRUCTION. in no case be less than… … Figure 121 an inch from the surface wired over, must be furnished withall snap switches used in exposed knob or cleat work. m. Mounting.—Pieces carrying contact jaws must be se-cured to the base by at least two screws, or else made witha square shoulder, or provided with dowel-pins or…
Electrical engineering
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