The SNSR3 SENSOR PHASE BAR FUSE TAP KIT (7141K1002) cannot be used in Sensor racks which were original Sensor Classic or Sensor+ and upgraded to Sensor3.
Explanation of Issue
In order for the kit to fit into the rack it must have suitable threaded PEM receptacles fitted to the bus bars of the rack. These receptacle exist in racks manufactured as Sensor3 racks, but not in Classic or +. The only way to get these in a rack which was originally Sensor Classic or Sensor+ but was upgraded to Sensor3 would be to replace the entire bus bar, and this is not recommended in the field.
If you need a tap, an electrician may be able to run one using the NEC "10 foot tap rule" but that is a matter for the electrician and AHJ