Battery issue

So I had a battery issue took it out let it sit on the charger all night voltage was go ik d so I went to reinstall it today I did the cables that are on the battery hooked then up positive then negitive then I went under the hood to hook the top ones up an did positive then negitive an when I went to do the negitive the negitive touched its ground wire that it typically attached to an it arched an tried to catch fire any ideas?