For all of you who like to intentionally short breakers to trace them: DON'T DO IT! I typically work old homes and its amazing how many breakers won't trip.
I'll second CalSparky, and add, there is no guarantee that the splices between the short and the breaker are solid. Especially in a dwelling that has a history of DIYer or handyperson twiddling. The fault current can easily series arc at a subpar splice and would not be noticed until the smoke got thick enough from the ignition of surrounding combustibles by that one tiny drop of molten conductor.
