Zone-Selective Interlocking (ZSI)
The number of devices which can be interlocked are shown in .
ZSI Combinations
| Downstream Device (sends output to RIM) | Upstream Device (receives input from RIM) → | |||||
|---|---|---|---|---|---|---|
| MicroLogic #.0x Trip Units | Square D MicroLogic Series B Trip Units | Square D GC-100 Ground-Fault Relay for Equipment Protection |
Square D GC-200 Ground-Fault Relay for Equipment Protection |
Merlin Gerin STR58 Trip Units | Federal Pioneer USRC and USRCM Trip Units | |
| MicroLogic #.0x Trip Units | 15 | R | R | 15 | 15 | R |
| Square D MicroLogic Series B Trip Units | R | 26 | R | R | R | 15 |
| Square D GC-100 Ground-Fault Relay for Equipment Protection | R | R | 7 | R | R | R |
| Square D GC-200 Ground-Fault Relay for Equipment Protection | 15 | R | R | 15 | 15 | R |
| Merlin Gerin STR58 Trip Units | 15 | R | R | 15 | 15 | R |
| Merlin Gerin STR53 Trip Units | 15 | R | R | 15 | 15 | R |
| Federal Pioneer USRC and USRCM Trip Units | R | 15 | R | R | R | 15 |
| Square D Add-On Ground Fault Module for Equipment Protection | R | 5 | R | R | R | R |
Jumpered Terminals |
Wire circuit breakers for zone-selective interlocking.
Circuit breaker terminals are shipped with terminals Z3, Z4 and Z5 jumpered to self-restrain the short-time and ground-fault functions. Remove the jumpers when activating zone-selective interlocking.
NOTE: Use I2t off with ZSI for proper coordination. Using
I2t on with ZSI is not recommended as the delay in the
upstream device receiving a restraint signal could result in the trip
unit tripping in a time shorter than the published trip curve.