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Adjustable and Fixed MCCB Solutions | 16A-1600A | Robust Circuit Protection

Reliable MCCB Supplier: UKM30 & UKM30RT Series

KKRIPAL offers a comprehensive range of molded case circuit breakers, centered around the robust UKM30 and UKM30RT series. The UKM30 serves as the standard fixed-trip solution, while the UKM30RT provides an enhanced, field-adjustable version with accessible thermal and magnetic settings on the front panel. The UKM30RT allows adjustment of thermal overload (0.7 to 1.0 times In) and magnetic protection (5 to 10 times In), enabling engineers to match circuit requirements without replacing the trip unit. Both series span 100AF to 630AF with breaking capacities up to 65kA at 400V AC, sharing identical accessories, mounting dimensions, and busbar connections. This makes the UKM30RT a seamless, drop-in upgrade for switchboards requiring field-adjustable protection for selective coordination. Certified to IEC 60947-2, both series ensure reliable performance for standard distribution and critical installations.

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Adjustable and Fixed MCCB Solutions | 16A-1600A | Robust Circuit Protection
UKM32 Adjustable MCCB 160A 3 Poles/4 Poles Moulded Case Circuit Breaker
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UKM32 Adjustable MCCB 160A 3 Poles/4 Poles Moulded Case Circuit Breaker

UKM32 series effectively suppresses short-circuit currents, protecting electrical equipment and power lines.

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UKM32 Adjustable MCCB 250A 3 Poles/4 Poles Moulded Case Circuit Breaker
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UKM32 Adjustable MCCB 250A 3 Poles/4 Poles Moulded Case Circuit Breaker

UKM32 Adjustable MCCB 250A for reliable overload and short-circuit protection in low-voltage distribution.

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UKM32 Adjustable MCCB 630A 3 Poles/4 Poles Moulded Case Circuit Breaker
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UKM32 Adjustable MCCB 630A 3 Poles/4 Poles Moulded Case Circuit Breaker

UKM32 Adjustable 4 pole MCCB circuit breaker 630A design for reliable low-voltage distribution short-circuit protection.

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UKM32 Adjustable MCCB 1250A 3 Poles/4 Poles Moulded Case Circuit Breaker

UKM32 Adjustable MCCB 1250A 3 Poles/4 Poles Moulded Case Circuit Breaker

UKM32 1250A moulded case circuit breaker 3P/4P, adjustable protection for low-voltage distribution.

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UKM30RT Adjustable MCCB 160A 3 Poles/4 Poles Moulded Case Circuit Breaker
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UKM30RT Adjustable MCCB 160A 3 Poles/4 Poles Moulded Case Circuit Breaker

Disjoncteur MCCB UKM30RT 160A 3P/4P for reliable protection of distribution circuits.

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UKM30RT Adjustable MCCB 250A 3 Poles/4 Poles Moulded Case Circuit Breaker
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UKM30RT Adjustable MCCB 250A 3 Poles/4 Poles Moulded Case Circuit Breaker

UKM30RT-250A for reliable overload and short-circuit protection in low-voltage distribution.

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Understanding Adjustable Thermal-Magnetic MCCBs

An adjustable MCCB, such as the UKM30RT, extends the standard UKM30 thermal-magnetic protection with field-adjustable trip settings, giving designers and engineers the flexibility to fine-tune protection to actual circuit conditions. The adjustable thermal setting allows overload protection to be matched to the cable’s actual ampacity (which may vary due to grouping, ambient temperature, or installation methods), while the adjustable magnetic setting enables precise coordination with downstream devices to achieve selective fault clearing. This guide covers the adjustment ranges and coordination capabilities of the UKM30RT, highlighting applications where adjustable protection provides a clear advantage over the fixed-setting UKM30 series.

UKM30 & UKM30RT MCCB Series Technical Specifications

Adjustable Thermal Overload Protection

The UKM30RT thermal trip is adjustable from 0.7 to 1.0 times In via a calibrated rotary dial, providing flexibility that exceeds the fixed protection of the UKM30 series. A 250A UKM30RT with the thermal setting at 0.8 In effectively becomes a 200A MCCB, allowing precise protection for specific cable ampacities using the same standard frame size as the UKM30. The thermal memory function is preserved at all settings. The adjustment dial is accessible from the front panel, and the setting remains visible through a window on the front cover. A tamper-evident seal can be applied to both series to prevent unauthorized access.

Adjustable Magnetic Instantaneous Protection

While the UKM30 provides fixed instantaneous protection, the UKM30RT magnetic trip is adjustable from 5 to 10 times In, enabling instantaneous pickup to be raised above a downstream device’s let-through current for selective coordination. For example, a 250A UKM30RT feeding a sub-distribution board with 63A MCBs allows the magnetic trip to be set to 7 In (1750A), ensuring downstream faults clear locally without tripping the upstream device. The magnetic trip adjustment is independent of the thermal setting, with factory-calibrated positions at 5, 6, 7, 8, and 10 In.

Selective Coordination with Downstream Devices

Selective coordination (discrimination) ensures that only the protective device closest to the fault operates, maintaining power to healthy circuits. While the UKM30 is ideal for standard distribution, the UKM30RT is the primary tool for achieving selective coordination in the instantaneous region. KRIPAL provides discrimination tables showing the maximum fault current at which the UKM30RT and a downstream device remain selective. For a typical 250A UKM30RT set to 8 In (2000A) feeding a 63A C-curve MCB, selectivity is maintained up to 3.5kA, covering sub-distribution boards located up to 50 meters away.

Commissioning and Periodic Testing

Both the UKM30 and UKM30RT settings should be recorded during commissioning and verified by primary injection testing. KRIPAL recommends a test set capable of injecting at least 120 percent of the set thermal and magnetic trip values. Test results serve as the baseline for periodic testing per IEC 60364-6. For the UKM30RT, trip settings should be reviewed every 5 years or whenever the circuit’s load profile changes. The adjustment dials feature a locking mechanism to prevent drift from vibration, with dial positions verified during annual inspections for both series.

Specify Adjustable MCCBs for Your Switchboard

  • Discrimination Study: Our engineers analyze your single-line diagram to determine the optimal configuration. We recommend UKM30 for standard distribution or provide calibrated UKM30RT settings with verified selectivity at every protection level to ensure fault clearing is isolated.
  • Commissioning Support: We provide comprehensive primary injection test procedures for both series. For critical projects, our team can witness the on-site testing to verify that both UKM30 and UKM30RT units are performing exactly to the specified set points.
  • OEM Supply: Source your MCCBs exactly how you need them. We provide both UKM30 and UKM30RT units factory-tested and, for the UKM30RT series, pre-set to your project’s specific values, ensuring they are ready for immediate switchboard integration.

Applications of Adjustable MCCBs

KRIPAL offers both UKM30 and UKM30RT MCCBs to meet diverse project requirements. The UKM30 series is the ideal, cost-effective choice for standard installations with stable load profiles. In contrast, the UKM30RT provides the protection flexibility needed for installations where circuit loading changes over time, where downstream devices are upgraded, or where initial design must be fine-tuned during commissioning. These field-adjustable settings transform the UKM30RT from a standard protection component into a highly configurable element that adapts precisely to evolving installation conditions.

Industrial Plant with Evolving Load Profile

A manufacturing plant’s sub-distribution board uses UKM30RT adjustable MCCBs on feeder circuits because production line configurations change every 2-3 years, avoiding the need to replace components like the standard UKM30. When a new 50 kW machine is added, the UKM30RT thermal setting can be adjusted upward (within cable limits) rather than swapping out the breaker. Conversely, if a load is reduced, the thermal setting is adjusted downward for closer overload protection, while the adjustable magnetic trip ensures selectivity with local MCBs is maintained.

Commercial Building Tenant Fit-Out Protection

A commercial office building’s floor distribution board uses UKM30RT MCCBs to feed each tenant’s sub-board, replacing rigid fixed-trip options like the UKM30. As tenant fit-outs change every 5-7 years, the electrical contractor can adjust the UKM30RT feeder protection to match the new tenant’s maximum demand without changing hardware. The adjustable magnetic trip is set to coordinate seamlessly with the tenant’s sub-board protection, regardless of varying brand preferences or ratings.

Generator Incomer with Seasonal Load Variation & Temporary Site Power

A standby generator at a seasonal facility utilizes a UKM30RT MCCB on the incomer, replacing standard UKM30 units to allow seasonal thermal adjustments (1.0 In during peak season and 0.8 In off-season) to prevent diesel engine wet stacking. Similarly, temporary construction site distributions use the UKM30RT to adapt daily to shifting trades, where the adjustable thermal setting matches changing loads while the adjustable magnetic trip prevents nuisance tripping from heavy motor inrushes.

Critical Infrastructure with Progressive Load Growth

A water treatment plant’s motor control center uses UKM30RT MCCBs on pump feeders to support a 10-year master plan expansion, offering a flexible alternative to the fixed UKM30 series. The breakers are initially installed with thermal settings adjusted to lower thresholds for early phases (e.g., 0.7 to 0.85 In) without replacing the hardware. These adjustable settings allow operators to defer capital expenditures on larger frame sizes until genuinely required, maintaining precise protection at every expansion stage.

Adapt Your Protection with Adjustable and Fixed MCCBs

  • Protection Review: Our engineers review your installation’s present and future load profile, recommending standard UKM30 units for stable circuits or calibrated UKM30RT settings for each stage of variable applications.
  • Discrimination Verification: Request time-current coordination tables for your adjustable UKM30RT settings alongside fixed UKM30 options with all downstream devices.
  • OEM Supply: Source UKM30RT MCCBs pre-set to your initial settings with adjustment instructions for future changes, alongside reliable UKM30 fixed breakers for standard requirements.
Applications of Adjustable MCCBs

KRIPAL Adjustable and Fixed MCCB Manufacturing and Support

KRIPAL adjustable and fixed MCCBs, such as the UKM30RT and UKM30 series, are manufactured on a combined production line where molded cases and contact mechanisms are precision-engineered to ensure robust industrial performance. Each adjustable MCCB undergoes multi-parameter calibration and mechanical verification to support reliable selective coordination and distribution protection.

Adjustable Thermal-Magnetic Protection Curve Calibration

The UKM30RT thermal-magnetic unit is calibrated to verify accurate tripping at all adjustable set-points: thermal overload pickup (0.7 to 1.0 times In) via calibrated rotary dials and magnetic short-circuit protection (5 to 10 times In). Each setting combination point on the time-current curve is verified to match precise circuit requirements without replacing the trip unit.

Reliable Mechanical Assembly and Component Verification

MCCBs configured with robust internal linkages and toggle mechanisms are tested for smooth operation: contact pressure, mechanical endurance, trip-free operation, and accurate manual open/close command execution. All internal components are functionally tested before final enclosure integration.

Front-Panel Cover and Window Assembly

The front-panel configuration, including the adjustment window for the UKM30RT and operational markings for the standard UKM30, is assembled and inspected for clear visibility of settings. Cover alignment, sealing provisions, and mechanical durability are checked on every unit.

End-of-Line Multi-Point Trip Verification

Each adjustable MCCB undergoes a multi-point trip verification: thermal tripping behavior at specified overloads and instantaneous magnetic tripping at the selected multiplier threshold. Trip characteristics at each verification point are compared against published tolerance bands and recorded against the serial number.

Distributor Stock Holding Programs for Adjustable MCCBs

KRIPAL supports distributor inventory programs with agreed stock levels for standard UKM30 models and commonly specified UKM30RT adjustable trip configurations. Technical support for trip unit setting coordination studies is included for volume distribution partners.

Private Label and OEM Branding for MCCB Series

Custom front-panel branding, OEM default configurations, and project-specific documentation are available for both the UKM30 and UKM30RT series. Neutral-packaged supply is provided upon request for private label production.

Multi-Region Certification and Compliance Support

CE, UKCA, and IEC 60947-2 compliance documentation are provided for both series. Type test reports with verified trip curves for all protection functions are available for panel builder compliance submissions.

Direct Technical Access to KRIPAL Application Engineers

Your technical team communicates directly with the engineers who designed the UKM30 and UKM30RT technical specifications and calibration procedures. Application questions including selectivity studies and protection coordination receive answers within 24 hours during China business hours.

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Frequently Asked Questions

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An adjustable moulded case circuit breaker is a circuit protection device that uses an electronic trip unit instead of a fixed thermal-magnetic mechanism. It protects electrical conductors and connected equipment against overload and short-circuit conditions, with the key advantage that all protection parameters including long-time pickup, long-time delay, short-time pickup, short-time delay, and instantaneous pickup can be adjusted in the field using rotary dials or digital interfaces. This adjustability allows one breaker model to serve multiple protection requirements, simplifies selective coordination with downstream devices, and enables protection settings to be modified as an installation's load profile changes over time without replacing the breaker.
KRIPAL adjustable MCCBs are available in frame sizes from 100A to 1600A with rated insulation voltage of 1000V and rated operational voltage of 690VAC. Short-circuit breaking capacity ranges from 35kA to 100kA at 415VAC depending on frame size and performance class. The electronic trip unit offers long-time pickup adjustable from 0.4 to 1.0 In, long-time delay adjustable per IEC 60947-2 curves, short-time pickup adjustable from 1.5 to 10 Ir, short-time delay adjustable from 0.05 to 0.4 seconds with I-squared-t selectable on/off, and instantaneous pickup adjustable from 2 to 12 In. Optional earth fault protection with adjustable sensitivity and delay is available. The trip unit is self-powered from internal current transformers, requiring no external auxiliary supply for protection functions. Operating temperature range is -5 to +70 degrees Celsius. Certifications include CE, CB Scheme, and IEC 60947-2 type test reports.
KRIPAL adjustable MCCBs are manufactured under ISO 9001 certified quality management. The product range carries CE marking and CB Scheme certification with IEC 60947-2 type test reports from KEMA and ASTA-recognised laboratories. Short-circuit breaking capacity has been verified at accredited independent test facilities for all frame sizes and voltage ratings. All products are RoHS compliant with REACH declarations maintained. For markets requiring national certification such as CCC for China, EAC for the Eurasian Customs Union, or specific Gulf Cooperation Council requirements, KRIPAL maintains certification documentation and can coordinate with local testing bodies. Full type test reports are provided to OEM partners and available to EPC contractors upon request.
Begin by determining the frame size based on the maximum continuous load current of the circuit, leaving headroom for future load growth. Select the breaking capacity class that exceeds the maximum prospective short-circuit current at the point of installation. Choose the trip unit configuration: standard LSIG protection covering long-time, short-time, instantaneous, and ground fault; LSI omitting ground fault for three-wire systems; or LS for applications where instantaneous protection is provided by a downstream device. Verify that the adjustable ranges for each protection function cover your coordination requirements. For energy management or BMS integration, specify the communication module option with Modbus RTU interface. Consider the installation environment: standard operating temperature range covers most indoor applications, but specify the extended temperature version for installations in unconditioned spaces or hot industrial environments. KRIPAL application engineers can review your single-line diagram, fault level calculations, and coordination requirements to recommend specific model numbers and initial settings.
Standard adjustable MCCB models in the most common frame sizes and current ratings are stocked at KRIPAL's Wenzhou warehouse with a lead time of 15 to 20 working days from confirmed purchase order. Non-standard configurations including specific communication options or extended temperature versions may require 25 to 35 working days. The minimum order quantity for standard models is 5 units per frame size. OEM partnership agreements can negotiate smaller minimums, scheduled deliveries, and consignment stock arrangements. Sample orders of 1 to 2 units for type testing or customer evaluation are available to qualified distributors. Shipping is arranged FOB Ningbo or Shanghai, with sea freight as the standard mode and air freight available for urgent requirements.
KRIPAL provides a 24-month warranty on adjustable MCCBs from date of shipment. Technical support includes application engineering for protection coordination, assistance with trip unit settings for complex installations, and troubleshooting of communication interfaces. KRIPAL supplies coordination study software to distributor partners that generates time-current curves for any combination of KRIPAL adjustable MCCBs and downstream protection devices, supporting the selectivity analysis required by many project specifications. For warranty claims, replacement breakers are shipped within 5 to 10 working days of confirmed defect depending on configuration. Spare trip units, terminal covers, and accessory kits are stocked for the full service life of each frame size. KRIPAL offers commissioning support for major projects, with engineers available to travel to site when arranged at time of order.

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