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 206
Figure 129 supporting screws and in the concealed type for the con-ductors also, and these openings should not be made anylarger than necessary. There must be at least one-quarter inch space, measuredover the surface, between supporting screws and current-carrying parts. The supporting screws must…
Electrical engineering
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