Square D PJL36120U44A Circuit Breaker Unit

Module Feature

PJL36120U44A is Square D PowerPacT P heavy-duty molded case circuit breaker.

It adopts 3-pole structure, rated current 1200A, 65kA ultimate short-circuit breaking capacity at 480V AC. It is pre-assembled with Micrologic 6.0A trip unit, which supports adjustable overload, short time delay, instantaneous short circuit and earth fault selective protection. It uses lug terminal connection, supports electrical operating mechanism and communication expansion module for SCADA remote monitoring. This series complies with UL489 North American specification, widely stocked as maintenance spare for oil & gas, factory and data center 600V low voltage distribution cabinet.

Working principle

Built-in current transformers collect three-phase current signals and send data to Micrologic 6.0A trip unit.

Electronic protection unit executes protection curve comparison in real time. When overload, short circuit or earth fault is detected, it sends trip command to release main contacts rapidly and isolate faulty circuit. Operation count, fault waveform and timestamp records are stored inside trip unit, and fault information can be uploaded to SCADA via communication module.

Onboard components

Main contact group, arc extinguishing chamber, CT sensor set, Micrologic 6.0A protection trip unit, spring operating mechanism, auxiliary contact block, alarm contact, front operation handle, status indicator window and reinforced insulated housing.

LED indicators

Front indicators show breaker ON, breaker OFF, fault trip status. Detailed protection parameter and fault code are displayed on Micrologic trip unit panel.

Hardware self‑diagnosis

Micrologic 6.0A trip unit runs continuous supervision for trip coil continuity, CT open circuit, internal power loss and hardware anomaly. Parameter configuration and fault log reading are completed by EcoStruxure Power Commission software.

Programming software

EcoStruxure Power Commission, used for protection curve setup, earth fault threshold, communication address and firmware upgrade.

Electrical & Process Parameters

Model:PJL36120U44A Brand:Square D (Schneider Electric) Device type:PowerPacT P molded case circuit breaker Function:Overload, short circuit and earth fault selective protection for 3-phase 600V low voltage main incoming and bus tie distribution circuit

Mechanical & Structure

Mounting:Switchgear cabinet fixed installation Protection class:IP30 front panel, IP20 terminal compartment Housing:Heavy-duty insulated MCCB housing

Environmental

Operating temperature:-10℃ ~ +55℃ Storage temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non‑condensing

Certification:UL489, CE Status:Original North American specification distribution spare

Installation

Isolate upstream power supply before replacement.

Check primary lug wiring and secondary control wiring, confirm 3-phase sequence, set protection parameters according to power distribution design, test manual/electric closing, tripping and earth fault protection function after commissioning.

Interface

Primary lug terminal for L1/L2/L3, secondary screw terminal block for auxiliary contact, alarm contact and communication signal.

Diagnostic

Cannot close: Interlock active, closing coil damage or trip latch locked. False earth fault trip: CT polarity reversed, neutral stray leakage or earth threshold improper setting. Communication offline: Bus termination resistance missing, cable damage or station address conflict.

Product Brief

PJL36120U44A circuit breaker, Square D PowerPacT P 1200A 3P 65kA@480V MCCB spare fo