Square D MJA36600 PowerPact M MCCB Unit

Module Feature

MJA36600 is a Square D PowerPact M frame moulded case circuit breaker. It is equipped with ET1.0 electronic trip unit, supports long-time overload and short-circuit protection. Rated current 600A, 3-pole, rated voltage 600VAC, interrupting capacity Icu 25kA at 600V. I-Line plug-in connection on line side, load side fitted with mechanical lugs. It follows 80% continuous rating rule, compatible with a full set of field-installable accessories such as auxiliary contacts, alarm switch and shunt trip. Widely stocked as spare for I-Line panelboards, factory LV switchgear and commercial power distribution cabinets.

Working principle

Internal current transformers collect three-phase current signals and send data to ET1.0 electronic trip controller. The processor compares real-time current with preset protection thresholds. Overload triggers inverse time delay trip, short-circuit fault triggers fast isolation of main contacts to protect cables and downstream loads. Auxiliary contacts output breaker ON/OFF and trip status signals to PLC or SCADA system.

Onboard components

Current transformer group, ET1.0 electronic trip controller, main contact assembly, arc quenching chamber, spring operating mechanism, I-Line plug-in bus connector, load terminal lugs, operation handle and insulated housing.

LED indicators

Front mechanical indicators show ON, OFF and trip status.

Hardware self‑diagnosis

Electronic trip unit monitors CT signal integrity and internal power supply. Protection parameters can be configured according to site requirement.

Programming software

Schneider dedicated protection configuration software for trip parameter setting and fault record review.

Electrical & Process Parameters

Model: MJA36600 Brand: Square D (Schneider Electric) Device type: Moulded case circuit breaker Rated current: 600 A Pole: 3P Rated voltage: 600 VAC Icu: 25 kA @600VAC Trip unit: ET1.0 electronic trip Mounting: I-Line plug-in Function: Overload and short-circuit protection for low voltage distribution feeders

Mechanical & Structure

Mounting: I-Line plug-in mounting inside switchgear Protection class: IP40 front panel Housing: Reinforced insulated plastic enclosure

Environmental

Operating temperature: -25℃ ~ +60℃ Storage temperature: -40℃ ~ +85℃ Ambient humidity: 5~95% non‑condensing

Certification: CE, UL480, CSA Status: Original Square D electrical distribution spare

Installation

Cut off upstream power supply before replacement. Align breaker with I-Line bus and lock in position, tighten load side lug connections, wire auxiliary or shunt trip accessories if installed, configure trip parameters, test close, open and protection action after commissioning.

Interface

I-Line plug-in line terminals, load side lug terminals, auxiliary contact terminals, shunt trip terminals.

Diagnostic

Overload trip: Continuous load current exceeds long delay setting. Short-circuit trip: Severe fault on downstream circuit. Failed communication: Trip unit power loss or wiring loose.

Product Brief

MJA36600 breaker, Square D PowerPact M 3P 600A I-Line plug-in MCCB spare for low voltage I-Line panel feeder protection replacement.