Installation relays are electromagnetically operated miniature contactors in the standard DIN width of 18 mm. A reliable control system can be designed using these ABB Installation relays E297. They are used mainly in industrial plants but also in commercial and public buildings. As a rule, installation relays operated by means of a control switch (maintained contact) are installed where it is necessary to operate lighting, an air-conditioning system, a fan or suchlike. Installation relays are also referred to as monostable switching relays or 2-pole miniature contactors. The term "monostable" means that an on command has to be sent to the coil by means of a control switch (maintained operation) in order to excite the magnetic coil. The coil armature attracts and closes or opens the main contacts. The device remains in the on position for as long as the control voltage is applied to the coil. If the voltage flow to the coil is interrupted, the installation relay always returns to the neutral position (off position). Installation relays and the accessories are available in different versions in order to easily satisfy the various market requirements. Their optimal switching capacity also makes them suitable for use in industrial environments and in situations where it is necessary to ensure control over more powerful consumers (such as e.g. multiple lighting ystems). Using an optimized coil (low power loss = lower operating temperature) ensures a clean and safe operation in the electrical distribution board.