The Eaton MDS-832 is an Insulated Case Circuit Breaker, part of Eaton’s Magnum DS family of low-voltage power circuit breakers. It is a robust and high-capacity electrical protection device designed for industrial and commercial applications.

Product Overview

The Eaton MDS-832 is a 3-pole, 3-phase insulated case circuit breaker with a high continuous current rating of 3200 Amperes. It is known for its high interrupting and withstand ratings, specifically 85kA at 480V/508V AIC (Amperes Interrupting Capacity). This breaker is designed for bolt-on mounting within switchgear and switchboards. As part of the Magnum DS family, it is engineered to provide superior protection, control, and monitoring capabilities for low-voltage electrical distribution systems. It often comes equipped with advanced microprocessor-based trip units (like the Digitrip series) for precise overcurrent protection, including long delay, short delay, and instantaneous functions, and potentially ground fault protection. The MDS-832 emphasizes safety, reliability, and ease of maintenance, making it a critical component in demanding electrical infrastructures.

Technical Specifications

Main Features and Advantages

The Eaton MDS-832 insulated case circuit breaker, as a member of the Magnum DS family, offers a compelling set of features and advantages for robust electrical protection:

High Interrupting and Withstand Ratings: The MDS-832 boasts an impressive 85kA interrupting capacity at 480V/508V. This high rating, combined with excellent short-time withstand capabilities, ensures superior protection against high fault currents, reducing damage to downstream equipment and enhancing overall system reliability and safety.

Compact Footprint: Eaton engineered the Magnum DS family, including the MDS-832, to offer greater capacity in smaller physical sizes. This allows for more circuit breakers per square foot within switchgear, optimizing panel space and potentially reducing construction costs for electrical distribution systems.

Advanced Microprocessor-Based Trip Units: Equipped with intelligent trip units (e.g., Digitrip series), the MDS-832 provides precise and customizable overcurrent protection. These units offer adjustable functions like long delay, short delay, instantaneous, and ground fault protection, enabling selective coordination and enhanced tripping sensitivity for improved system reliability and less nuisance tripping.

Enhanced Safety Features: The Magnum DS design incorporates multiple safety features, such as through-the-door access to trip unit controls, clear visual indicators (open/close flags, spring charge/discharge flags), and isolated secondary wireways. Optional features like arc-resistant designs further mitigate arc flash hazards, protecting personnel and equipment.

Ease of Maintenance and Wiring: The breaker is designed for ease of maintenance, with features like readily accessible secondary wiring points, finger-proof hinged covers for secondary terminals, and a design that facilitates access to internal components (e.g., for replating operating mechanisms or upgrading trip units). Its bolt-on mounting is straightforward for installation within switchgear.

Two-Step Stored-Energy Closing: This mechanism ensures reliable and consistent closing operations, even into fault conditions, contributing to the breaker’s overall robustness and longevity.

100% Rated Protection: The MDS-832 is designed to be 100% continuous current rated in its enclosure, meaning it can carry its full rated current continuously without requiring derating, which simplifies system design and maximizes power utilization.

Application Field

The Eaton MDS-832 insulated case circuit breaker is designed for demanding low-voltage power distribution applications where high continuous current ratings, superior fault protection, and robust construction are essential. It is primarily used in conjunction with switchgear and switchboards.

Key application fields include:

Heavy Industrial Facilities:

• Manufacturing Plants: Protecting main incoming feeders, large motor control centers, and critical machinery in factories, including automotive, metalworking, and pulp and paper industries.
• Mining, Minerals, and Metals: Essential for power distribution in challenging environments, protecting large conveyors, crushers, and processing equipment.
• Oil and Gas: Providing primary and secondary overcurrent protection in refineries, petrochemical plants, and offshore platforms, where continuous operation and safety are paramount.

Commercial and Institutional Buildings:

• Large Commercial Complexes: Protecting main electrical services and large distribution panels in office buildings, shopping centers, and convention centers.
• Healthcare Facilities: Ensuring reliable power distribution in hospitals and clinics, particularly for critical systems.
• Data Centers: Providing robust overcurrent protection for critical power distribution units (PDUs) and server racks, crucial for maintaining uptime.

Infrastructure and Utilities:

• Electric Utilities: Used in substations, power generation plants (thermal, hydro, renewable), and large distribution networks to protect transformers, feeders, and other electrical apparatus.
• Water/Wastewater Treatment Plants: Protecting pump stations, motor control centers, and other electrical equipment in water treatment and distribution systems.

Critical Power Applications:

• Service Entrance: Serving as the main protective device at the point where utility power enters large commercial or industrial facilities.
• Multiple Source Transfer Systems: Providing overcurrent protection and switching capabilities in automatic transfer schemes involving utility power and backup generators.

In essence, the MDS-832 is deployed wherever a high-amperage, high-interrupting capacity circuit breaker is needed to ensure safe, reliable, and selective protection of complex low-voltage electrical distribution systems.

Related Products

The Eaton MDS-832 is a core component within Eaton’s Magnum DS family of circuit breakers and is often integrated into larger electrical distribution systems. Related products include:

Eaton Magnum DS Low-Voltage Power Circuit Breakers (other models):

• Other Amperage Ratings: Other breakers within the Magnum DS family (e.g., MDS-408, MDS-616, MDS-C32) that offer different continuous current ratings (from 800A up to 6000A) but share similar design principles and features.
• Different Interrupting Ratings: Magnum DS also includes models with 65kA (e.g., MDS-632) or 100kA (e.g., MDS-C32, MDS-C40) interrupting capacities at various voltages.
• Drawout Versions: While the MDS-832 is often bolt-on, Magnum DS breakers are also available in drawout construction for easier maintenance and replacement.

Eaton Magnum SB Insulated-Case Circuit Breakers:

• Designed for UL 891 switchboard applications, offering similar performance characteristics to Magnum DS but tailored for different enclosure types.

Eaton Magnum Series NRX Circuit Breakers:

• A newer generation of Eaton’s low-voltage power circuit breakers, often used as replacements or upgrades for Magnum DS in modern switchgear, offering enhanced features and digital capabilities.

Eaton Digitrip Trip Units:

• Microprocessor-based trip units (e.g., Digitrip 520, 520i, 520MCi, 11ARMLSI) are essential accessories for the MDS-832, providing customizable overcurrent protection and metering functions.
• Rating Plugs (e.g., 2A11891G01) are used with these trip units to set specific continuous current ratings.

Eaton Low-Voltage Switchgear and Switchboards (Magnum DS Switchgear):

• The enclosures and busbar systems specifically designed to house Magnum DS circuit breakers like the MDS-832. These include integrated control/measuring devices, protective relays, and communication capabilities.

Eaton Power Xpert Protection Manager:

• Software and hardware solutions for advanced monitoring, control, and coordination of electrical distribution systems, often integrating with Magnum DS breakers.

Eaton Automatic Transfer Switches (e.g., ATC-900 controller):

• Used in critical power applications, these devices work in conjunction with circuit breakers like the MDS-832 to manage power transfer between multiple sources (e.g., utility and generator).

Eaton Remote Racking Devices (e.g., MRR1000):

• Tools designed to remotely rack in or out drawout Magnum circuit breakers, enhancing operator safety during maintenance by mitigating arc flash exposure.

Eaton Breaker Accessories:

• Shunt trips, undervoltage releases (UVRs), auxiliary contacts, bell alarms, and other accessories that enhance the functionality and control of the MDS-832.

Installation and Maintenance

Pre-installation preparation: Before installing the Eaton MDS-832 Insulated Case Circuit Breaker, it is absolutely critical to ensure that all power to the switchgear or switchboard compartment is completely de-energized and locked out following strict Lockout/Tagout (LOTO) procedures. Always refer to the official Eaton Magnum DS installation and operation manual (e.g., IB2C12060H08) for detailed instructions, wiring diagrams, and safety warnings. Verify that the mounting provisions in the switchgear cell are compatible with the MDS-832’s bolt-on configuration. Carefully inspect the breaker for any shipping damage. Ensure that the associated trip unit and any accessories (shunt trips, auxiliary contacts) are correctly specified and prepared for installation. All cable lugs should be appropriate for the 3200A rating and properly mounted. Use appropriate lifting equipment due to the breaker’s substantial weight.

Maintenance recommendations: Regular and thorough maintenance of the Eaton MDS-832 is crucial to ensure its long-term reliability and proper operation, aligning with industry standards like NETA, UL 1066, UL 489, and ANSI C37.

• De-energize System: Always de-energize and safely isolate the breaker and associated circuits before any maintenance, testing, or cleaning.
• Visual Inspection: Conduct regular visual inspections (e.g., annually) for signs of overheating (discoloration), loose connections, excessive dust or debris, and damage to the insulation, arc chutes, or operating mechanism.
• Cleaning: Clean the breaker surfaces, especially the arc chutes and contact areas, using approved non-conductive cleaning solvents and lint-free cloths. Remove any accumulated dust or foreign material from inside the breaker compartment.
• Contact Inspection: For drawout breakers, inspect the primary disconnects and main contacts for wear, pitting, or alignment issues. Though the MDS-832 is bolt-on, accessible contact points should be checked if possible.
• Lubrication: Lubricate the operating mechanism with the type and amount of lubricant specified by Eaton. This typically involves the charging mechanism, linkages, and moving parts to ensure smooth operation.
• Mechanical Checks: Manually operate the breaker (open/close) to ensure the mechanism moves freely and smoothly. Verify proper spring charge and discharge. Check the functionality of all interlocks (e.g., rejection interlocks, position interlocks) and safety shutters.
• Trip Unit Testing: Periodically perform primary or secondary injection testing of the microprocessor-based trip unit to verify its accuracy and functionality. This ensures the breaker will trip correctly under fault conditions. Refer to the specific Digitrip manual for testing procedures.
• Accessory Checks: Test all installed accessories (e.g., shunt trip, undervoltage release, auxiliary switches) for proper operation.
• Torque Checks: Verify that all bolted connections, particularly the primary power connections, are tightened to the manufacturer’s specified torque values.
• Documentation: Maintain detailed records of all inspection, testing, and maintenance activities, including dates, findings, and actions taken. For complex maintenance or repairs, it is highly recommended to engage qualified and certified electrical technicians or Eaton-authorized service personnel.

Product Guarantee

The Eaton MDS-832 Insulated Case Circuit Breaker, as a product from a leading electrical manufacturer, comes with a standard product guarantee from Eaton, affirming its commitment to quality, safety, and reliability. This guarantee typically covers defects in materials and workmanship for a specified period from the date of purchase (common for industrial electrical equipment).

Key aspects of the product guarantee usually include:

• Warranty Coverage: The warranty generally covers faults or failures that arise due to manufacturing defects or material flaws under normal operating conditions.
• Remedy: In the event of a covered defect, Eaton’s standard policy usually involves repair or replacement of the defective breaker at their discretion. Replacement units may be new or refurbished, but will be functionally equivalent.
• Compliance: As a product designed to meet ANSI, UL, and CSA standards, the guarantee reinforces its adherence to these rigorous performance and safety benchmarks.
• Limitations: The warranty typically does not cover damage resulting from improper installation, misuse, neglect, unauthorized modifications, operation outside specified ratings, or natural disasters. Normal wear and tear of consumable components (e.g., contacts, arc chutes after repeated fault interruptions) may also be excluded.
• After-Sales Support: Eaton provides extensive technical support for its Magnum DS circuit breakers, including troubleshooting assistance, access to technical documentation, and a network of authorized service centers. This support is crucial for the long operational life of such a critical component.

When purchasing the MDS-832, especially from surplus or reconditioned markets, it’s vital to clarify the specific warranty offered by the seller, as it may differ from Eaton’s original factory warranty. Reputable reconditioners often provide their own guarantees, sometimes for periods comparable to new equipment, ensuring the breaker conforms to relevant industry standards like NETA.