The most common form of surge protection offered by consumer products is Type 3 surge protection, which is used in parallel with consumer electronics at the load end of an outlet. Type 1 protection is a permanent installation that protects the whole electrical system from outside sources of surges, including lightning strikes and utility switching. In contrast, Type 2 protection is a permanent installation that protects from surges caused within a system, as in the case of air conditioners or other large appliances.