oil switchn. a switch or circuit-breaker in which the contacts are immersed in oil.
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the world > matter > physics > electromagnetic radiation > electricity > circuit > circuit-breaker > [noun] > switch
oil switch1904
trip switch1924
1904 Trans. Amer. Inst. Electr. Engineers23 215 The design of the oil-switch lends itself readily to operation by control from a distance.
1964 E. A. ReevesInstallation & Maintenance Industr. Switchgear iii. 57 The type of oil switch described is essentially a fault-making and load-breaking device.