An entirely reasonable point. Might have to import one from the States, then, since they're on 110V over there. =]

In my defence, however, demolition hammers have been used on combat robots before - the RW Wiki informs me that a hardy beast called Roter Osche competed with one powered by an 8.5HP petrol engine back in the days of the Second Wars. Admittedly, it was a superheavyweight that weighed in at ~167kg, but that can probably be put down to '90s-era materials and build styles. =]