TM 10-6640-215-13 4-17. REMOVE/INSTALL EMERGENCY LIGHT BALLAST- continued. d. Connect ballast plug to connector. e. Close and latch shut ballast box door. 4-18. REMOVE/INSTALL EMERGENCY LIGHT BALLAST BOX. This task covers:   a. Removal b. Installation INITIAL SETUP: Tools Required General Mechanics Tool Kit, (Appendix B, Section III, Item 2) Equipment Condition Power to lights turned OFF by placing A1CB9, A1CBI 1, and AICB13 in the OFF position at Main Power Panel. General Safety Instructions WARNING ELECTRICAL SHOCK Before performing any maintenance actions on electrical equipment, ensure all electrical power has been turned off.  Death or serious injury may occur from failure to do this. REMOVAL Remove Ballast Box.  See figure 4-6. a. Tag and disconnect wires to plug connector from lighting circuit. b. Remove hex nut that secures electrical conduit elbow to ballast box bracket. c. Remove four screws, flat washers, and lock washers from rivnuts mounted on semi-trailer van wall. d. Guide wires from lighting circuit through conduit opening while removing ballast box from wall mounting. INSTALLATION Install Ballast Box.  See figure 4-6. a. Guide wires from lighting circuit through conduit opening while positioning new ballast box to wall mounting. b. Secure ballast box to rivnuts of wall mounting with four lock washers, flat washers, and screws. c. Secure electrical conduit elbow to ballast box bracket with hex nut. d. Connect wires from lighting circuit to plug connector.  Remove tags. 4-36