Galvanic isolation is often identified with an intrinsic safety isolator
While a zener diode barrier is normally the most cost-effective solution, the intrinsic safety isolator using galvanic isolation is normally the superior, long-term performance solution. This is because galvanic isolation and the additional electronics used within intrinsic safety isolators provide better noise immunity, signal conversion options, application-specific designs, no intrinsic safety ground connection/maintenance requirements, signal enhancement, logic control features, and fewer impedance concerns.
The term galvanic isolation is often linked to and identified with an intrinsic safety isolator. This is because intrinsic safety isolators use galvanic isolation components such as transformers, relays, and capacitors. Both the zener barrier and IS isolator are used to provide energy limitation to circuits/components mounted in hazardous ‘classified’ locations.
Since these hazardous locations are ignition capable, it is important to provide a reliable means of limiting energy that can be transmitted so an explosion hazard is not created during normal or fault operation of the circuit. So, the decision to use an intrinsic safety isolator (galvanic isolation) or zener barrier really comes down to the application.