start a 420CC engine, and I'm only looking at the single-instance use of an "external" battery to start it. one time only deal. I agree that replacing battery every other year is good preventive maintenance. However, that doesn't preclude a recently purchased battery that croaks due to "Murphy".
back to my main question, will 12gage stranded wire handle sufficient current to do the job? the cable would be a dual (positive & negative) quick-disconnect connection at the battery, and the end at the car will have proper marked/insulated clamps to connect at the battery. the wife that may be using this is a technically proficient person quite capable of doing things correctly under stress. She can easily pull-start the engine, I've witnessed her doing so several times while helping her & husband learn to operate the generator/transfer switch operation. TIA