1. In combination, a high voltage circuit comprising three conductors each located at the apex of a triangle, a powerline pole supporting said conductors extending laterally thereof, frame means in a plane generally at right angles to said conductors and secured to the upper end of said pole including a horizontal frame member and a vertical frame member secured to said horizontal frame member intermediate its ends, and a disconnecting switch assembly mounted on each end of said horizontal frame member and on the upper end of said vertical frame member near the respective apex of said triangle and connected to the respective conductor for interconnecting adjacent sections thereof.

2. Disconnecting switch construction for interconnecting conductors of a three-phase high voltage circuit each located at the apex of a triangle and for mounting on a powerline pole comprising: frame means adapted to be secured to the upper end of said pole including a horizontal frame member and a vertical frame member secured to said horizontal frame member intermediate its ends, a disconnecting switch assembly mounted on each end of said horizontal frame member and on the upper end of said vertical frame member with each switch assembly located near each apex of said triangle, and operating means on said frame means mechanically interconnecting said disconnecting switch assemblies for conjoint operation thereof between open and closed positions.

5. Disconnecting switch construction for interconnecting conductors of a three-phase high voltage circuit each located at the apex of a triangle and for mounting on a powerline pole comprising: frame means adapted to be secured to the upper end of said pole including a horizontal frame member and a vertical frame member secured to said horizontal frame member intermediate its ends, a disconnecting switch assembly mounted on each end of said horizontal frame member and on the upper end of said vertical frame member with each switch assembly located near each apex of said triangle, each switch assembly including a stationary contact and a cooperating switch blade carried by an insulator, means pivotally mounting the insulators of the switch assemblies at the ends of said horizontal frame member endwise thereof, means pivotally mounting the insulator of the switch assembly at the upper end of said vertical frame member transversely thereof; shaft means interconnecting said insulators of said switch assemblies at the ends of said horizontal frame member, and link means interconnecting said insulator of said switch assembly at the upper end of said vertical frame member and said shaft means to effect conjoint operation of said switch blades into and out of engagement with the respective stationary contact.

9. Disconnecting switch construction for interconnecting conductors of a three-phase high voltage circuit each located at the apex of a triangle and for mounting on a powerline pole comprising: frame means adapted to be secured to the upper end of said pole including a horizontal frame member and a vertical frame member secured to said horizontal frame member intermediate its ends, a disconnecting switch assembly mounted on each end of said horizontal frame member and on the upper end of said vertical frame member with each switch assembly located near each apex of said triangle, each switch assembly including a stationary contact and a cooperating switch blade carried by an insulator, means pivotally mounting the insulators of the switch assemblies at the ends of said horizontal frame member endwise thereof, means pivotally mounting the insulator of the switch assembly at the upper end of said vertical frame member transversely thereof, and an insulator support bracket secured to each end of said horizontal frame member and to the upper end of said vertical frame member for supporting an insulator at one end on the other end of which the respective stationary contact is mounted, each of said support brackets having an inner end section for mounting flatwise against the respective end of the respective frame member, an intermediate section extending at an obtuse angle from said inner end section, and an outer section extending at right angles from said intermediate section for mounting the respective contact carrying insulator in angular relation to the respective pivoted insulator.

10. In combination, a high voltage circuit comprising two sets of three conductors in endwise relation constituting a three-phase powerline with corresponding conductors each located at the apex of a triangle, a powerline pole supporting said conductors extending laterally thereof, inverted cross-shaped frame means in a plane generally at right angles to said conductors with the upright piece secured to the upper end of said pole and the ends of the upright and transverse pieces each being located near the respective apex of said triangle, a disconnecting switch assembly mounted at each of said ends of said upright and transverse pieces, operating means on said frame means mechanically interconnecting said disconnecting switch assemblies for conjoint operation thereof between open and closed positions, and dead end means near each of said ends of said upright and transverse pieces to which said conductors can be dead ended for connection to the respective switch assembly.

16. Disconnecting switch construction for interconnecting conductors of a three-phase high voltage circuit each located at the apex of a triangle and for mounting on a power line pole comprising: inverted cross-shaped frame means with the upright piece adapted to be secured to the upper end of said pole and the ends of the upright and transverse pieces each being located near the respective apex of said triangle, a disconnecting switch assembly mounted at each of said ends of said upright and transverse pieces, operating means on said frame means mechanically interconnecting said disconnecting switch assemblies for conjoint operation thereof between open and closed positions, dead end means near each of said ends of said upright and transverse pieces to which said conductors can be dead ended for connection to the respective switch assembly; each switch assembly including a stationary contact and a cooperating switch blade carried by an insulator and means pivotally mounting the insulators of the switch assemblies at said ends of said upright and transverse pieces, said operating means being connected to said insulators; and an insulator support bracket secured to each end of said horizontal frame member and to the upper end of said vertical frame member for supporting an insulator at one end on the other end of which the respective stationary contact is mounted, each of said support brackets having an inner end section for mounting flatwise against the respective end of the respective frame member, an intermediate section extending at an obtuse angle from said inner end section, and an outer section extending at right angles from said intermediate section for mounting the respective contact carrying insulator in angular relation to the respective pivoted insulator.