At first glance, the concept of Intrinsically-Safe (I.S.) fieldbus is a study in opposing concepts. After all, fieldbus is about powering multiple devices, while the idea of I.S. is to limit energy flowing into hazardous areas. The fact that multiple devices can be powered from the same wire pair only adds to the design challenges that engineers face when developing their own systems. Typically, this can lead to complex installation schemes as users mix wiring methods such as Division 1 and Division 2 (Zones 0, 1 and 2) in order to accomplish their task.