Search FAQs

This FAQ has been written for NEAL (North East Africa and Levant) region. If you are looking for information for another region, please select the correct country from the top-left dropdown in the page and 'Navigate to Browse FAQs' in the Support menu.

What is the possibility of using Zone Selectivity Interlocking (ZSI) between upstream (NSX160-250) & downstream (NSX160-250)?

To use the ZSI function between 2 Compact NSX MCCBs; one in the upstream and the other in the downstream, one of them will have to be a Compact NSX400~630 to contain the terminals Z3, Z4 and Z5. These terminals are the ones to which the downstream MCCB should be connected to. Compact NSX100~250 MCCBs do not contain these terminals (Z3, Z4 and Z5) and thus won't be able to perform the ZSI function if placed in the upstream/downstream combinations. Please refer to the attached pages from the Micrologic trip unit user manual (refer to "Extract - Compact NSX - Micrologic 5 or 6 - User manual.pdf"). So to make use of the ZSI function between 2 Compact NSX MCCBs, please make that the upstream breaker is Compact NSX400~630.