The Eaton MDS-820 is an Insulated Case Circuit Breaker, a key component of Eaton’s (formerly Cutler-Hammer) Magnum DS family of low-voltage power circuit breakers. It’s designed for heavy-duty electrical protection in industrial and commercial distribution systems.
Product Overview
The Eaton MDS-820 is a 3-pole, 3-phase insulated case circuit breaker with a continuous current rating of 2000 Amperes. It is distinguished by its high interrupting and withstand ratings, specifically 85kA at 480V/508V AIC (Amperes Interrupting Capacity), and also at 600V. Designed for bolt-on mounting within switchgear and switchboards, the MDS-820 provides robust overcurrent protection for main, feeder, and tie breaker applications. Like other breakers in the Magnum DS line, it incorporates advanced microprocessor-based trip units (such as the Digitrip series) that offer precise, adjustable protection functions including long delay, short delay, and instantaneous, often with optional ground fault protection. The MDS-820 emphasizes superior safety, operational flexibility, and ease of maintenance, making it suitable for critical electrical infrastructures where high fault currents and reliable operation are paramount.
Technical Specifications
Main Features and Advantages
The Eaton MDS-820 insulated case circuit breaker, part of the Magnum DS family, offers several key features and advantages for high-performance electrical protection:
High Interrupting and Withstand Ratings: The MDS-820 features a robust 85kA interrupting capacity at various voltages up to 600V. This high rating, combined with excellent short-time withstand capabilities, provides superior protection against high-magnitude fault currents. This minimizes damage to downstream equipment, enhances system reliability, and improves overall safety.
Compact Standard Frame Size: Eaton’s Magnum DS breakers are engineered to offer high current and interrupting ratings in a relatively compact physical footprint. This allows for optimized space utilization within switchgear and switchboards, potentially reducing the overall size and cost of electrical distribution equipment.
Advanced Microprocessor-Based Trip Units: Equipped with intelligent Digitrip series trip units, the MDS-820 provides highly customizable and precise overcurrent protection. These units offer adjustable long delay, short delay, instantaneous, and often ground fault functions, enabling selective coordination to isolate faults rapidly while minimizing the unaffected portions of the electrical system.
Enhanced Safety Features: The Magnum DS design prioritizes safety, incorporating features such as through-the-door access to trip unit controls, clear visual indicators for breaker status (e.g., open/close, spring charged/discharged), and isolated secondary wireways. These features simplify operation and maintenance while reducing exposure to energized parts.
Ease of Maintenance and Wiring: Despite its robust construction, the MDS-820 is designed for ease of maintenance. Features like front-accessible secondary wiring terminals and readily removable arc chutes facilitate quicker inspections and servicing. Its bolt-on design for fixed mounting simplifies installation into compatible switchgear.
100% Continuous Current Rated: The MDS-820 is often designed to be 100% continuous current rated in its enclosure. This means it can carry its full 2000 Ampere rated current continuously without requiring thermal derating, which optimizes power utilization and simplifies system design.
Two-Step Stored-Energy Closing Mechanism: This mechanism ensures powerful and reliable closing operations, even into fault conditions, contributing to the breaker’s robust performance and longevity.
Application Field
The Eaton MDS-820 insulated case circuit breaker is ideally suited for critical low-voltage power distribution applications where robust protection, high continuous current handling, and reliable fault interruption are paramount. It is primarily integrated into switchgear and switchboards in various industrial and commercial settings.
Key application fields include:
Heavy Industrial Facilities:
- Manufacturing Plants: Protection for main incoming feeders, large motor control centers, and significant machinery in diverse manufacturing sectors such as automotive, pulp and paper, and heavy machinery production.
- Mining and Metals: Essential for power distribution in harsh environments, protecting large motors, crushers, and material handling systems used in mining and metallurgical processes.
- Oil and Gas: Providing primary and secondary overcurrent protection in refineries, petrochemical plants, and offshore platforms, where continuous operation, high fault current protection, and personnel safety are critical.
Commercial and Institutional Buildings:
- Large Commercial and Public Buildings: Used for protecting main electrical services, large distribution panels, and critical loads in office towers, shopping malls, airports, convention centers, and educational institutions.
- Healthcare Facilities: Ensuring highly reliable power distribution in hospitals and medical centers for critical patient care systems and life support equipment.
- Data Centers: Providing robust overcurrent protection for vital power distribution units (PDUs) and server infrastructure, which is crucial for maintaining continuous uptime of IT systems.
Infrastructure and Utilities:
- Electric Utilities: Employed in substations, power generation plants (conventional and renewable), and large distribution networks to protect transformers, feeders, and other electrical apparatus.
- Water/Wastewater Treatment Plants: Protecting pump stations, motor control centers, and various electrical equipment in water treatment and distribution systems.
In summary, the MDS-820 is deployed in any large electrical system that requires a high-amperage, high-interrupting capacity circuit breaker for safe, reliable, and selective protection of complex low-voltage power distribution.
Related Products
The Eaton MDS-820 is a fundamental component of Eaton’s Magnum DS family and is designed to work within comprehensive electrical distribution systems. Related products typically include:
Eaton Magnum DS Low-Voltage Power Circuit Breakers (other models):
- Other Amperage Ratings: The Magnum DS family includes breakers with various continuous current ratings (e.g., MDS-808, MDS-616, MDS-832, MDS-C40) ranging from 800A up to 6000A, sharing similar design characteristics with the MDS-820.
- Different Interrupting Ratings: Magnum DS breakers are available with other interrupting capacities (e.g., MDS-620 with 65kA, MDS-C20 with 100kA).
- Drawout Versions: While the MDS-820 is typically bolt-on, many Magnum DS breakers are also available in drawout configurations for easier maintenance and replacement.
Eaton Magnum SB Insulated-Case Circuit Breakers:
- Similar in function and performance to Magnum DS, but specifically designed for UL 891 switchboard applications.
Eaton Magnum Series NRX Circuit Breakers:
- A newer generation of Eaton’s low-voltage power circuit breakers, often considered for modern installations or as upgrades to existing Magnum DS systems, offering advanced features and digital capabilities.
Eaton Digitrip Trip Units:
- Essential microprocessor-based trip units (e.g., Digitrip 520, 520i, 520MCi, 11ARMLSI) that are installed in the MDS-820 to provide adjustable overcurrent protection and metering functions.
- Rating Plugs (e.g., 2A11891GXX): Used with Digitrip units to set the specific continuous current rating of the breaker.
Eaton Low-Voltage Switchgear and Switchboards (Magnum DS Switchgear):
- The primary enclosures and busbar systems specifically designed to house and integrate Magnum DS circuit breakers like the MDS-820. These often include integrated control, metering, and communication capabilities.
Eaton Power Xpert Protection Manager:
- Software and hardware solutions for advanced monitoring, control, and coordination of electrical distribution systems, which can communicate with and manage Magnum DS breakers.
Eaton Automatic Transfer Switches (e.g., ATC-900 controller):
- Used in critical power applications to manage the transfer of power between multiple sources (e.g., utility and generator), often utilizing breakers like the MDS-820 as switching devices.
Eaton Remote Racking Devices (e.g., MRR1000):
- Safety tools designed for the remote racking in or out of drawout Magnum circuit breakers, which enhance operator safety during maintenance by reducing arc flash exposure (though less relevant for bolt-on MDS-820, it’s part of the family ecosystem).
Eaton Breaker Accessories:
- Various accessories like shunt trips, undervoltage releases (UVRs), auxiliary contacts, and bell alarms that enhance the control, remote operation, and signaling capabilities of the MDS-820.
