One more point as to current and resistance. An average car battery can crank out ninety amps or better at 12 vdc. You would be hard pressed to even feel it if you touched both posts. 277 vac at even 10 amps would tend to ruin your day.
I have a device that uses a 555 timer, a couple of pots and an autotransformer (car engine coil); it can go to blow-out frequencies and about 40,000 volts using two nine volt batteries. I couldn't electrocute a cockroach.
A 480 gallon bucket is going to weigh a lot more than an 18 gallon bucket, but it is the raincoat that keeps you from getting wet.