An electrician working in the United States today can expect to either specialize in construction or maintenance. However, ever-increasing numbers of electricians in the United States now do both, as is the norm in many other countries. Those who specialize in construction install the electrical systems (including outlets, lighting, switches and so forth) in factories, homes and businesses. They may upgrade systems when needed as well. Those who are specialized in maintenance repair and maintain already extant electrical systems. They may also work on electrical equipment repair. There is a great deal of crossover between the two types.