A two-digit number established by the International Electro Technical Commission, is used to provide an Ingress Protection rating to a piece of electronic equipment or to an enclosure for electronic equipment. The protection class after EN60529 are indicated by short symbols that consist of the two code letters IP and a code numeral for the
Solenoid ON for only a short time, usually not more than 2 or 3 minutes, then followed by an OFF time which is normally at least as long as the ON time. This ON time and OFF cycling can be repeated continuously over the total life of the solenoid.
International Electrotechnical Commission System for certification to standards relating to equipment for use in explosive atmospheres.