The Protective Termination Expander Board (TCEB), scales the PT and CT signals used by the TCCB board. These signals are used for the generator and bus voltages and the line current and are landed on the PTBA terminal board. Signals for emergency overspeed and flame detect come from the PTBA terminal board and are passed through the TCEB board to the TCEA boards for processing. The 335 V dc needed for the flame detector devices passes across this board from the TCEA boards, is conditioned, sent to the PTBA terminal board and out to the sensors. The alarm horn for the Mark V LM is also located on the TCEB board