Thanks guys.... They are both self-resetting circuit breakers, they're both exactly the same size, with the same size terminals and the same configuration. Plymouthy Adams
suggestion is the best one so far, and the way I'll do that is by assuming that one of them is the 30 amp, hook up all the wiring on that basis and if the headlights are flashing when I power it up, I'll know that I got it backwards. The leads are long enough that I can easily switch between the two breakers. Just using the headlights as the load is the easiest way to do it.
Meanwhile, if anybody knows which one is which, it might save me an hour or so if I could hook them up correctly the first time.
Again, thanks for your help.
All the Best, Chip