If a lot of dust accumulates in the enclosure or water easily enters, it may cause malfunction and generate heat or sparks. Therefore, the IEC standard (IEC 60529 regulation) classifies the equipment according to the degree of protection from external contact, dust, and water (moisture). This is called Ingress Protection, commonly referred to as IP.
IK grade is widely used as the protection grade against external physical impact. Physical mechanical force is applied and the resulting measurement is expressed in J (joules).