A valuable use of adjustable circuit breakers is protection of the track from excess power available from base stations or boosters. If you're only running 2 or 3 engines, you should set the current limit to a couple of amps, since you shouldn't need more than that.
This will protect you if a locomotive derails and starts drawing current but not quite enough to trip the master breaker.
It takes an iron man to play with a toy iron horse.
I have an NCE Power Cab system with an SB5 booster. Just purchased the EB1 to protect my SB5. I thought this would be a simple matter of connectng the SB5 to the EB1 and then connecting the EB1 to the track. The instruction do say to do that but they also talk on page 4 about "setting up" the EB1 and "fine tuning" the EB1. Is all that really needed? I have a 14' x 18' u-shaped HO layout and will likely never run more than 2 0r 3 locos at any time. I would like to keep this simple.
Thanks
wdcrvr