I often use a fine needle and insert it through the insulation of a wire, much like if you were giving it a "shot". I then use small alligator clips to attach to the needles. This way I can check each load carrying electrical circuit for its amperage draw. This can be accomplished with or without the engine running and I will check both ways during troubleshooting. It is unlikely that you getting a "bad" breaker each time you replace it and more likely you have one (or more) circuits drawing an excessive amount of current. Another method is to add electrical loads one at a time and measure the total amperage output as each load is added. Be it something in the lighting, sound system, gauges, etc. is causing your breaker to open.