Off-topic thread started here: http://www.hearth.com/talk/threads/who-burns-24-7.92094/page-3#post-1208258 I don't really understand the question, as that typically depends on our neighbor's usage. One transformer will feed several houses in a neighborhood. In the case of our house, we use so much electric, one might assume we're heating with it. The internal resistance of a typical marine or RV battery is higher than that of a car battery, but still frighteningly low. The 2500 amp number came from a manufacturer of marine batteries. That number cannot be maintained without overheating the battery (recall, exploding / boiling battery acid flying about), so you could never run a 60 kilowatt continuous load, or discharge in the time you suggest. Fuses have one trip mechanism: thermal. There is a time vs. load curve for any fuse, as they do take time to overheat and burn open. Circuit breakers typically have two trip mechanisms, magnetic and thermal. Magnetic trip is designed for short circuit or severe overload protection, whereas the thermal trip mechanism is designed for simple overload protection, and has a slow time vs. current behavior. In either case, you're bound for some excitement in the event of a true short circuit, but I do suspect you will be safe from an overheating / exploding battery situation... unless the short happens upstream of the fuse! There must be something to that story beyond what you heard or relayed. The effects of current on the human body have been thoroughly studied over the years. OSHA, notoriously conservative, puts minimum current for respiratory arrest at 17 mA. Most sources are closer to 100 mA. Developing even 17 mA from a 1.5 volt battery would require a net resistance of 88 ohms, most likley in a path thru the victim's chest cavity. Simply put, there is no possible way anything close to that is happening.