The Apollo 55000-720APO is a short circuit isolator. The Apollo 55000-720APO is placed at intervals on the loop and ensures that, in case of a short circuit, only the section between the isolators will be affected. When the short circuit is resolved, the 55000-720APO will automatically restore power and data to the isolated section.
The 55000-720APO can only be used with an Apollo Isolator Base, and will not fot the standard addressable bases.