Burglar Alarm.—Furnish and install complete burglar alarm system consisting of the necessary wires, window springs, door springs, night latch cutout for front door, bell, batteries, cabinet, interconnection strip, etc., and everything required for a complete open-circuit system. Each window sash and door throughout the building shall be equipped with contact spring of approved make and all springs on same side of building on each floor shall be wired on one circuit and terminated on single-pole knife switch on interconnection strip. The interconnection strip shall be located as directed and shall have cutout switches for each circuit as well as a double-pole battery switch. The battery shall consist of at least three dry cells in suitable cabinet placed where directed and both positive and negative leads shall be carried direct to interconnection strip. The burglar-alarm wires shall be not less than No. 16 B. & S. gage, insulated and installed as specified for call bells.
Intercommunicating Telephones.—Furnish and install an intercommunicating telephone system complete with all telephone sets, wiring, batteries, etc. All wires to be cables containing one pair of No. 22 B. & S. gage conductors for each station and a pair of No. 16 B. & S. gage conductors for talking and ringing battery respectively. Each pair of wires shall be twisted and all pairs shall be twisted around each other to eliminate cross talk and inductive noises. The wires shall be silk insulated, with a moisture repellent of beeswax or varnish and the whole covered with a lead sheath at least 1⁄64 inch in thickness. Where cables terminate in outlet boxes they shall be fanned out and laced in an orderly manner and secured to connecting terminals, one of which shall be provided for each wire. Install where directed in an approved cabinet at least four cells of dry battery each, for talking and ringing purposes.
Installation of Interphone Cable.—Intercommunicating cables shall be supported with pipe straps and liberal clearance shall be observed where near steam or other pipes.
Automatic Door Switch.
—Where indicated on the plan, clothes closets shall be equipped with automatic door switch to connect the light when the door is open.
Fig. 266 is placed in the door frame in such position that electric contact is made by release of the projecting pin as the door is opened. When the door is closed, the pin is depressed and the light is extinguished
Plug Receptacles.
—Plug receptacles shall be selected from the styles shown in Figs. 267,a, b, c or d.
