Engine Electrical Systems (1) Electrical circuit protection devices are rated based on the amount of current that can be carried without overheating the wiring insulation. (2) A “trip-free” circuit breaker makes it impossible to manually hold the circuit closed when excessive current is flowing. Regarding the above statements, a. only No. 1 is true. b. only No. 2 is true. c. both No. 1 and No. 2 are true.