If the fuse in the box is rated higher than that intended for the circuit, excessive current will be allowed to flow and possibly overload the outlet and house wiring to the point that a fire can begin. Be certain that correct-size fuses are used. If all, or nearly all, fuses used are 30-amp fuses, there is a chance that some of the fuses are rated too high for the circuit. These safety features reduce the risk of an electric shock. Consider replacing old tools that have neither a 3-prong plug nor are double insulated.
Power tools used with guards removed pose a serious risk of injury from sharp edges or moving parts.
Replace guards that have been removed from power tools. Improperly grounded appliances can lead to electric shock. Check with your service person or an electrician if you are in doubt. Check containers periodically to make sure they are tightly closed. CPSC has reports of several cases in which gasoline, stored as much as 10 feet from a gas water heater, exploded.