Posted on: July 1, 2014
SELV: Separated Extra Low Voltage. This circuit must be safely separated from other circuits that carry higher voltages, isolated from earth and isolated from the protective earth conductors of other circuits.
The design of an SELV circuit typically involves an insulation transformer, guaranteed minimum distances between conductors and insulation barriers. The connectors of SELV circuits should also be designed to that they do not make with connectors commonly used for non-SELV circuits.