I just completed an FAA required recurrent course for the aircraft I fly. The Power Point program & instructor teach that a wire with 75 amp rated current limiters at each end will provide 150 amps of load before one or both current limiters melts and opens the circuit. The use of the current limiters is a modification to replace a single 450 amp rated reverse current circuit breaker. Instead of one line with a 450 amp RCCB between the main battery and the main bus, three parallel lines are used with current limiters at each end of each line. The advantage of the three parallel lines is to not lose all power to the bus if only one or two of the three parallel lines opens.
The explanation given is that total resistance in a series circuit is the sum of the individual resistances; therefore, six 75 amp current limiters (one at each end of the three parallel lines) will allow the same sustained current as the single 450 amp reverse current circuit breaker.
I disagree and I've read that each current limiter is rated at 150 amps and each of the parallel lines will allow a sustained current of 150 amps. By analogy, if a line has current limiters at each end, one rated at 75 amps and one rated at 50 amps, the circuit will open with a sustained current in excess of 50 amps, not a total of 125 amps.