Trip Unit Installation

Inspect trip unit connector pins and surfaces. If there is any damage, misaligned pins, or contamination, stop installation and contact the local sales office for factory authorized service.
Inspect trip unit mounting base on the circuit breaker. Clear any debris from area and check that all accessory wiring is properly routed for the trip unit being installed. If there is any damage or contamination, stop installation and contact the local sales office for factory authorized service.
For MasterPact NW circuit breaker only: Manually depress trip unit interlock (A) and hold it in place during steps 4–6 below.

Align guide rail (B) on bottom of trip unit with guide rail slot (C) on trip unit mounting base in circuit breaker and gently slide the trip unit in until it stops.

NOTE: The MasterPact NT and NW trip unit mounting bases are shock mounted and therefore can flex slightly.

Install Trip Unit

CAUTION
Hazard of equipment damage Check installation of trip unit to assure proper connections and seating. Failure to follow these instructions can result in injury or equipment damage.

Align the trip unit so top mounting screw (A) aligns with the top threaded insert and start the screw by turning the screw two full rotations.
Use a torque-controlled screwdriver to drive the bottom screw (B) to 7 in-lbs (0.8 N•m) ± 10%. The back of the trip unit must be flush with the trip unit mounting base.
Use a torque-controlled screwdriver to drive the top screw to 7 in-lbs (0.8 N•m) ± 10%. Mounting tab must be flush with the mounting standoff and sensor plug.

NOTE: The face of the closed switch cover must be flush with adjoining mounting base surfaces. If these surfaces are not flush, stop installation and contact the local sales office for factory authorized service.

NOTE: If you are upgrading from a MicroLogic 2.0, 3.0 or 5.0 trip unit, the connector block must be ordered separately (Part Number S33101). See instructions shipped with the connector block for installation into circuit breaker.
Install connector block (C) into top of trip unit.

Secure Trip Unit
Install adjustable rating plug into the trip unit.

a. Open switch cover (A) on new trip unit.

b. Inspect mounting area for debris and contamination.

c. Gently push adjustable rating plug (B) into new trip unit.

d. Tighten adjustable rating plug mounting screw (C). The plug will be drawn into position flush with front face as screw is tightened.
Set trip unit switches and advanced protection settings to values recorded above or per coordination study results.
Close switch cover (A).

Install Adjustable Rating Plug

Trip Unit Installation

Install Trip Unit

Secure Trip Unit

Install Adjustable Rating Plug