Unless you have some sick peoples in your houshold, the "antibacterial" cycle is only wastefull as within minutes after you get the dishes out of the washer, thousands of bacterias will land on everything.
Anyway, given the temperature of the water and the detergents used, there is normaly no bacterias left to suppress for the so called antibacterial setting.
On that cycle, the power requirement is very slightly exceeding the power rating of the circuit, placing it perpetualy on the verge of tripping. In that cituation, any slight random power glitch can cause the breaker to trip. That's why it don't always happenat the same moment, and occasionaly may not trip at all.
Next, over time, the heater may loose some of it's effeciency and the thermal isolation can degrade, increasing the heating requirement.
Electro, May 2012
