Technical Specifications

FAQ

1. What is the main function of the NS800N circuit breaker?

The Schneider NS800N is a high-current molded case circuit breaker designed for low-voltage power distribution systems. Its primary functions include circuit switching, overload protection, and short-circuit protection when equipped with a compatible trip unit. When abnormal current conditions occur, the breaker interrupts the affected circuit to help prevent damage to cables, transformers, switchboards, and connected electrical equipment. It is suitable for industrial distribution panels, main power feeders, transformer protection circuits, and large machinery installations.

2. What is the rated current of the NS800N?

The NS800N has a rated current of 800 A, making it suitable for industrial applications that require high current-carrying capacity. The actual operating current should be evaluated according to ambient temperature, load characteristics, conductor capacity, and installation conditions. The selected trip unit and its protection settings also affect the operating characteristics of the breaker. When purchasing a replacement, engineers should verify the complete product reference, number of poles, and trip unit configuration to ensure compatibility with the existing electrical system.

3. What is the short-circuit breaking capacity of the NS800N?

The NS800N belongs to the N breaking-capacity class. Its rated ultimate short-circuit breaking capacity is 50 kA at 415 V AC, 85 kA at 220/240 V AC, and 30 kA at 660/690 V AC, depending on the specific configuration. These values indicate the maximum fault current the breaker can interrupt under specified test conditions. Before installation, the prospective short-circuit current at the installation point must be calculated and compared with the breaker’s rated breaking capacity. Proper coordination with upstream and downstream protective devices is also necessary for reliable system protection.

4. Which electronic trip units are available for the NS800N?

Depending on the exact product configuration, the NS800N can be equipped with different MicroLogic electronic trip units, such as MicroLogic 2.0, 2.0E, and 5.0 versions. These trip units provide different protection functions and adjustment capabilities. Common functions include long-time overload protection and instantaneous short-circuit protection. Certain versions also provide short-time protection, which is useful when coordination between upstream and downstream circuit breakers is required. Before replacing a trip unit, verify its compatibility with the breaker frame, current rating, and required protection characteristics.

5. Why does the NS800N trip unexpectedly during normal operation?

Unexpected tripping may result from sustained overloads, downstream short circuits, high motor starting currents, ground faults, or incorrectly adjusted protection settings. Loose electrical connections and deteriorated cable insulation can also cause abnormal operating conditions. Troubleshooting should begin by checking the trip unit indication to identify which protection function has operated. Engineers should then measure the actual load current, inspect downstream cables and equipment, and verify the protection settings. If repeated tripping occurs, the coordination between upstream and downstream protective devices should also be reviewed. The breaker should not be repeatedly reset without identifying the underlying fault.

6. What is the difference between fixed and drawout NS800N configurations?

The fixed version is installed directly onto a mounting structure inside the electrical switchboard, with permanent main circuit connections. It is suitable for installations where frequent removal of the breaker is unnecessary. The drawout version uses a dedicated chassis that allows the breaker to move between connected, test, and disconnected positions. This arrangement makes inspection, maintenance, and replacement more convenient, particularly in large industrial power distribution systems. Since the two configurations use different mounting structures and connection accessories, the original installation type must be confirmed before ordering a replacement.

7. Can the NS800N be integrated with PLC, DCS, and industrial automation systems?

Yes. With compatible auxiliary contacts, electronic trip units, and control accessories, the NS800N can be integrated into PLC, DCS, and power monitoring systems. Auxiliary contacts can provide breaker open and closed status signals, while compatible electronic trip units may provide protection information and electrical measurements. For remote switching applications, an appropriate motor operating mechanism and control circuit are required. Before integration, engineers should verify accessory compatibility, control voltage, signal characteristics, and available communication functions to ensure reliable operation with the existing automation system.

8. What maintenance procedures are recommended for the NS800N?

Regular preventive maintenance helps maintain reliable operation and reduce unexpected power interruptions. Inspections should cover the main circuit terminals, insulation components, contact system, mechanical operating mechanism, and electronic trip unit. Check for overheating, corrosion, loose connections, insulation deterioration, and abnormal mechanical wear. For breakers equipped with MicroLogic trip units, protection settings, fault records, and trip functions should also be checked according to the manufacturer’s maintenance recommendations. If the breaker has interrupted a significant short-circuit current, its internal contacts and arc-extinguishing components should be professionally inspected before being returned to service. All maintenance work must be performed by qualified electrical personnel after proper power isolation and safety verification.