There are two main types of environmental ratings being dealt with when talking about power rated switches. The first is the ingress protection rating, also known as the IP rating. The IP rating is a 2-digit number. The first digit denotes the degree of protection against solids, and the second digit refers to the degree of protection against liquids. Some common IP ratings for switches are listed on this page. The second type of environmental rating is the NEMA rating, which typically refer to enclosures.