8.2.2 Electrical Systea The istertal electrical system for all cattiers ccusists af two timers, a times juoccica box, and chree caples. A fourth cable is required in the bouster. The exter=ai electrical system consists of a jettisonable control cable to each Stage of the webicle, launcher jumction box, and remote araing box. The timers are motor-driven and provide three separate times, adjustable from zero to 220 seconds for the instrimsent vehicles and from zero to ALO seconds for the sampler vehicles, Wormally closed contacts are used in conjunction vith a relay in the timer junctica box to provide the required fourth time. The timers are munted on the bulkbead inside the pressurized nose cone on the instrumeot carriers and in the midsection on the sampler. The timer junction boz provides all the circuits betwen the pressurized nose compartment and the aft sections of the carrier, with facilities for disconnecting these electrical connections af nose separation. are also enclosed in the box. Relays and fuses required for timer operation Connections from the timer junction box to the control cable conrector, motcr igniter squibs, and aft instrument compartzents, when used, ave provided by three cables. A fourth cable provides a control , cable connector to the booster igniter on all two-stage vehicles. The control cable# prowiding circuitry from the launcher junction box to the rocket are furnished with a spring-loaded breakzway connector. A small steel cable between the connecror and che launcher trips the latch on the conpector at first movement of the carrier, allowing the spring to eject the cable. The lamcher junction box routes all circuits from the telemetering control box, the ECAC timing relay used to fire the rocket motor, and the 30 VDC extecaal power source to the vehicle via the control cable. The launcher contains the firing relay which provides a firing or safing signal for the potorigniter and cizer-start circuits and a key interlock switch which prevents closing of the firing circuit except from the remote araing box. Also provided are two lights to monitor the timers in the carrier, one light to monitor positica of the key iaterlock switch, and one lamp to indicate safe condition of the ECAG tinirg relay. The resote arzing box is located a minizam of 800 feet from the nearest wehicle and is comected to the launcher junction box by a four-conductor at fy shielded cable. The key from the key switch in che launcher junction box is sens v