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MCCB Accessories Motor Operators Shunt Trips Rotary Handles | UKM Series
Factory-made accessories for smarter power protection
KRIPAL manufactures a comprehensive range of MCCB accessories for the UKM1 series, enabling extended functionality beyond basic overcurrent protection. The accessory range includes shunt trip releases for remote tripping via an external control signal, undervoltage releases that trip the MCCB when the supply voltage drops below a set threshold, motor operators for remote opening and closing via PLC or SCADA control, rotary handle mechanisms with door interlock and padlock facility for local operation and isolation, auxiliary contacts (up to 4 changeover) for status signaling, alarm contacts that signal when the MCCB has tripped on a fault, terminal shrouds for IP2X finger protection, phase barriers for increased insulation between adjacent MCCBs, and plug-in and withdrawable conversion kits that convert a fixed MCCB to a drawout configuration for rapid replacement without disconnecting busbar connections. All accessories are designed for tool-free installation, clipping or screwing onto the MCCB body, and are fully compatible across all UKM1 frame sizes. CE and UKCA marked, KRIPAL MCCB accessories are used by switchboard manufacturers to build functionally complete switchboard assemblies from a single supplier’s component ecosystem.
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MCCB Accessory Guide: Remote Operation and Safety Integration
MCCB accessories extend the basic protection function into a complete circuit management solution that integrates with the building’s control, monitoring and safety systems. A motor operator enables the MCCB to be remotely controlled from a PLC or SCADA system, supporting automated load transfer, peak shaving and remote circuit restoration. Shunt trip and undervoltage releases integrate the MCCB with fire alarm systems and emergency stop circuits. Auxiliary and alarm contacts provide status feedback for remote monitoring. The rotary handle mechanism and door interlock provide the local operator interface that meets the safety requirements for switchboard access. This selection guide covers each accessory type, its electrical ratings, mechanical compatibility and typical application.
UKM1 MCCB Accessories Technical Specifications
Motor Operators for Remote Control
The UKM1 motor operator is an electric motor-driven mechanism that mounts on the front of the MCCB and drives the toggle mechanism to open or close the main contacts. It accepts control signals at 24V DC, 48V DC, 110V AC or 230V AC, with the motor inrush current limited by an internal soft-start circuit. The operator includes mechanical status indicators (ON, OFF, TRIP) visible from the switchboard front, and the MCCB can still be operated manually via an external handle if the motor supply fails. The motor operator is rated for 10,000 operations and includes a manual charging lever for closing the MCCB against the contact spring mechanism when commissioning the switchboard without the motor supply energized. Typical applications include automatic transfer switches (ATS), where the motor operator on the generator incomer closes automatically when the utility supply fails, and remote load restoration in unattended substations.
Rotary Handle and Door Interlock Mechanisms
The rotary handle mechanism replaces the standard toggle handle with a panel-mounted rotary handle connected to the MCCB via an extension shaft. The handle provides clear ON, OFF and TRIP position indication visible from the front of the closed switchboard door, with the TRIP position indicating that the MCCB has opened on a fault (as opposed to manual switching to OFF). The door interlock mechanism prevents the switchboard door from being opened while the MCCB is in the ON position, but can be deliberately defeated by a qualified person using a tool for diagnostic measurements. The OFF position accepts up to three padlocks with a 6mm shackle diameter for multi-contractor lockout-tagout compliance. The rotary handle is available in standard black or red-yellow emergency color scheme, with an optional IP65-rated shaft seal for weatherproof switchboard enclosures.
Shunt Trip and Undervoltage Release Integration
The shunt trip release is available in 24V DC, 48V DC, 110V AC and 230V AC coil voltages, operating the MCCB trip mechanism when the coil is energized for at least 50ms. The coil is rated for intermittent duty (energized for no more than 5 seconds to avoid overheating), and the external control circuit must include a contact that opens after the MCCB trips to de-energize the coil. Typical applications include fire alarm panel integration (the alarm panel’s auxiliary output energizes the shunt trip to disconnect power to the affected building zone) and emergency stop circuits. The undervoltage release (UVR) trips the MCCB when the supply voltage drops below 70-35 percent of nominal, and prevents the MCCB from being reclosed until the voltage recovers above 85 percent. The UVR is used for motor circuits where automatic restart must be prevented, and for lighting circuits in areas where sudden darkness creates a safety hazard.
Auxiliary Contacts and Plug-In/Withdrawable Kits
Auxiliary contacts (1CO or 2CO changeover, rated 250V AC 3A) provide remote signaling of the MCCB open/closed status, mechanically linked to the main contact toggle for positive indication of the actual contact position. The alarm contact (1CO) signals when the MCCB has tripped on a fault (overload, short-circuit or earth leakage), allowing the BMS or SCADA system to distinguish between a manual disconnection and a fault trip. The plug-in and withdrawable conversion kits replace the fixed MCCB mounting with a plug-in base or a drawout carriage, allowing the MCCB to be replaced without disconnecting the busbar and cable connections. The plug-in version uses spring-loaded power contacts that engage when the MCCB is pushed into the base, while the drawout version uses a racking mechanism that moves the MCCB from the connected position through a test position to an isolated position, with auxiliary contacts signaling each position to the SCADA system.
Specify Accessories for Your MCCB Installation
- Accessory Schedule: Provide your MCCB list and we specify the correct accessories with part numbers for each device.
- Switchboard Layout Support: Request 2D panel layout drawings showing handle cutout positions and interlock mounting details.
- OEM Supply: Source UKM1 MCCBs pre-fitted with your specified accessories, factory-tested and ready for switchboard integration.
Remote Switching for Automatic Transfer and Substation Automation
KRIPAL UKM1 MCCB accessories transform a basic overcurrent protection device into a connected, remotely controllable and safety-integrated circuit management system. From the motor operator on a generator incomer in an automatic transfer switch to the rotary handle and door interlock on a switchboard feeder, these accessories are the interface between the MCCB, the building control system and the human operator.
Automatic Transfer Switch with Motor Operators
An automatic transfer switch (ATS) panel uses two UKM1 MCCBs fitted with motor operators: one on the utility incomer and one on the generator incomer. During normal operation, the utility MCCB is closed and the generator MCCB is open. When the ATS controller detects a utility supply failure (under-voltage, phase loss or frequency out of range), it sends an open command to the utility MCCB motor operator, waits for the auxiliary contact to confirm the MCCB is open, starts the generator, and once the generator voltage and frequency are stable, sends a close command to the generator MCCB motor operator. The entire transfer sequence completes within 10-15 seconds, with the mechanical interlock between the two MCCBs (using a key exchange or a cable interlock) preventing both sources from being connected simultaneously, a catastrophic failure mode that would back-feed the generator supply into the utility network.
Fire Alarm Integration with Shunt Trip Releases
A commercial building’s main LV switchboard uses shunt trip releases on the MCCBs feeding air conditioning, ventilation, escalator and lift circuits. When the fire alarm panel detects a fire condition, it sends a 24V DC signal to the shunt trip coils on these MCCBs, disconnecting power to the mechanical services that could spread smoke and fire through the building. The alarm contacts on the same MCCBs signal the fire alarm panel that the circuits have been successfully isolated, providing a closed-loop confirmation that the fire safety action has been completed. The shunt trip circuit is wired in a fail-safe configuration: a broken wire or loose terminal in the shunt trip circuit prevents the MCCB from being reclosed after a fire event, requiring a manual inspection and reset.
Switchboard Door Interlock for Operator Safety
A factory main switchboard uses rotary handles with door interlock mechanisms on all UKM1 feeder MCCBs. The door interlock prevents the switchboard door from being opened while any MCCB is in the ON position, protecting the operator from accidental contact with live busbars and terminals. When maintenance is required on a specific feeder, the operator switches that MCCB to OFF, padlocks the handle, and can then open the door to access the outgoing cable terminations while the rest of the switchboard remains energized. The door interlock can be deliberately defeated by a qualified electrician using a special tool (a 3mm Allen key inserted into a hidden release), allowing diagnostic voltage measurements on energized circuits per the exception in IEC 60947-1 for competent personnel.
SCADA Remote Monitoring with Auxiliary and Alarm Contacts
A water pumping station’s SCADA system monitors the status of all UKM1 feeder MCCBs via auxiliary and alarm contacts wired to the RTU digital inputs. The auxiliary contact (closed when MCCB is ON) confirms that each pump feeder is energized, and the alarm contact (closed when MCCB has tripped on fault) generates an immediate alarm on the SCADA screen, alerting the control room operator to a pump trip. The combination of auxiliary and alarm contacts allows the SCADA to distinguish between a pump intentionally switched off for maintenance (auxiliary open, alarm not activated) and a pump that has tripped on a fault (auxiliary open, alarm activated), directing the operator’s response accordingly.
Drawout MCCB for Rapid Replacement in Critical Applications
A data center’s critical power distribution uses UKM1 MCCBs in drawout configuration on the UPS output feeders. If an MCCB develops a fault (failed trip unit, welded contacts) or requires upgrading to a higher rating due to increased server load, the drawout mechanism allows the maintenance electrician to rack the MCCB out to the isolated position, remove it from the carriage, and insert a replacement, all without disconnecting the busbar and cable terminations at the rear of the switchboard. The total replacement time is under 15 minutes, compared to 2-3 hours for a fixed MCCB that requires disconnecting and reconnecting busbar bolts, maintaining the data center’s power availability target of 99.999 percent uptime.
Specify MCCB Accessories for Your Switchboard
- Integration Design: Our application engineers design the accessory configuration for each MCCB in your switchboard, including wiring schematics for motor operator and shunt trip circuits.
- Factory Assembly: Order MCCBs pre-assembled with all specified accessories, factory-tested and shipped with individual test certificates.
- OEM Partnership: Dedicated accessory stockholding and JIT delivery for switchboard manufacturers with ongoing UKM1 production requirements.
KRIPAL MCCB Accessory Manufacturing: Precision Integration
KRIPAL MCCB accessories including motor operators, shunt trips, undervoltage releases, rotary handles, and plug-in kits are manufactured in a dedicated accessories production cell. Each accessory type is assembled, functionally tested, and mechanically verified for compatibility with the full MCCB frame size range for global switchboard builder applications.
Motor Operator Assembly with Auto/Manual Selector
Motor operators are assembled from a geared DC motor, limit switch cam assembly, and a manual override handle with padlock facility. Each motor operator is functionally tested for remote ON-OFF-RESET operation and verified for the mechanical interlock that prevents simultaneous manual and motor operation. Endurance testing at 5000 operations is performed on sample units from each production batch.
Shunt Trip and Undervoltage Release Production Testing
Shunt trip coils are wound in-house and tested for operation across the 70 to 110 percent rated voltage range. Undervoltage releases are calibrated to trip when voltage drops below the specified threshold and to prevent MCCB reclosure until voltage recovers above 85 percent. Each release is tested for mechanical compatibility with all applicable MCCB frame sizes.
Rotary Handle and Door Interlock Verification
Direct-mount and door-mounted rotary handles with shaft extension kits are assembled with the padlock mechanism and door interlock defeat feature. Sample handles from each batch are tested for 2000 mechanical operations and verified for the interlock function that prevents door opening when the MCCB is ON. IP65 handle variants are water-jet tested.
Plug-In and Withdrawable Kit Assembly
Plug-in base modules and withdrawable cassettes are fabricated with silver-plated contact clusters rated for the full MCCB current. Each kit is tested for contact resistance after 50 insertion/withdrawal cycles using a four-wire micro-ohmmeter. The mechanical interlock that prevents insertion/withdrawal when the MCCB is ON is verified on every kit.
Distributor Stock Holding Programs for MCCB Accessories
KRIPAL supports distributor inventory programs with agreed stock levels for standard accessory models across all frame sizes. Bulk packs and accessory kits for common panel configurations are available for volume distributors.
Private Label and OEM Branding for MCCB Accessories
Neutral-packaged accessories with OEM part numbering and distributor-branded installation instructions are available. KRIPAL supports the supply of accessories configured to match specific MCCB product ranges for integrated distribution programs.
Multi-Region Certification and Compliance Support
CE, UKCA, and relevant IEC standard compliance documentation is provided for all accessory types according to target export markets. Technical files are maintained for evolving regulatory requirements.
Direct Technical Access to KRIPAL Production Engineers
Your technical team communicates with the engineers who designed and tested your MCCB accessories. Application questions including accessory retrofitting to field-installed MCCBs receive answers within 24 hours during China business hours.
Frequently Asked Questions
Explore FAQ >Yes, motor operators and most accessories are designed for field installation on existing UKM series MCCBs without removing the MCCB from the panel.
Yes, KRIPAL rotary handles accept up to 3 padlocks in the OFF position for Lockout/Tagout compliance during maintenance.
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