An interior door does not have to withstand extreme weather changes. Interior and exterior doors are not the same product sold under different labels. The construction of each is different, with exterior doors given special treatment to stand up to the elements and frequent use.
The charging of lead-acid batteries can be hazardous. However, many workers may not see it that way since it is such a common activity in many workplaces. The two primary risks are from hydrogen gas formed when the battery is being charged and the sulfuric acid in the battery fluid.
When electrons move through a conductor an electric current is created. A current that always flows in one direction is called a direct current (DC). A battery for example, produces a direct current. A current that flows back and forth is called an alternating current (AC). battery has liquid or paste in it that helps it produce electric charges. The flat end of the battery has a negative charge and the end with the bump has a positive charge. When you link a wire between both ends a current flows.