DOUBLE ARMS A double arm should be used at line terminals, at corners, at angles, or at other points when there is an excessive strain (fig. 4-14). When lines cross telephone circuits or railroad crossings, double arms also should be used, as more than ordinary safety is required at such points. When two or more transformers are mounted on the same pole, double arms, as a rule, are used for their support.

Figure 4-13.- Single-arm construction.

Figure 4-14.- Double-arm construction.

Figure 4-15.- Buck-arm construction.

Figure 4-16.- Side-arm construction.

Figure 4-17.- Standard flat-strap crossarm brace.

BUCK ARMS Buck arms are used at comers and at points when branch circuits are taken off at right angles to the main line (fig. 4-15).

SIDE ARMS Side arms are used in alleys or other locations when it is necessary to clear buildings. (See fig. 4-16.)