AC Adjustable Current MCCB

Essential Technical Selection & Adjustment Factors

Current Adjustment Range & Trip Technology:

Adjustable Thermal-Magnetic Trip Units: Feature calibrated rotary dials allowing field adjustment of thermal overload pickup (Ir, typically 0.8×In to 1.0×In) and fixed or adjustable instantaneous short-circuit protection (Ii).

Adjustable Electronic / Microprocessor Trip Units: Offer multi-stage, high-precision adjustment dials (Io,Ir,Isd,Ii,Ig) for advanced selectivity, ground fault protection, and time-delay settings, preventing nuisance tripping in complex networks.

Frame Sizes & Current Ratings (In): Available across compact 63A frame sizes up to heavy-duty 1600A frame units, allowing consistent mounting architecture across Main Distribution Boards (MDBs) and sub-panels.

Breaking Capacity (Icu/Ics) & kARatings: Evaluate ultimate short-circuit breaking capacity (Icu) up to 100kA at 400V/415V to handle high fault levels. NUOMAK adjustable MCCBs offer high service breaking capacity ratios (Ics=100%Icu on select models) to maintain system integrity post-fault.

Quality Standards & Testing Compliance

All NUOMAK AC Adjustable Current MCCBs are produced under ISO9001 quality management systems and strictly comply with IEC/EN 60947-2 switchgear safety standards. Each unit undergoes 100% factory routine testing—including dielectric withstand, mechanical switching trials, and precise thermal/electronic trip calibration—guaranteeing compliance with regional electrical codes across European, Asian, Middle Eastern, and American markets.

Key Industrial Applications

Switchgear & Control Panel Builders: Simplifies panel standardization by allowing a single frame size to cover multiple operational current ratings via field adjustment.

Industrial Motor Protection & Feeder Distribution: Provides customized overload protection curves matching heavy industrial motor startup currents and transformer secondary circuits.

Commercial Real Estate & Data Centers: Essential for selective protection coordination, minimizing outage areas during fault events in high-availability environments.

How do field adjustments (Ir/Isd) work on NUOMAK AC Adjustable Current MCCBs?

On Thermal-Magnetic models, thermal overload current (Ir) can be adjusted via front rotary dials (typically between 80% and 100% of rated current In​). On Electronic models, digital or analog selectors enable independent tuning of long-time overload pickup (Ir), short-time delay pickup (Isd), instantaneous pickup (Ii), and ground fault pickup (Ig), facilitating precise selective coordination with upstream and downstream protective devices.

What OEM and custom branding options does NUOMAK offer for adjustable MCCBs?

NUOMAK offers comprehensive OEM/ODM customization for regional electrical distributors and equipment manufacturers. Customization options include private label laser engraving, custom housing/dial handle colors, tailored nameplates, customized packaging, and factory-fitted accessories such as Shunt Trip Coils (MX), Undervoltage Releases (MN), and Auxiliary Contacts.

What is the Minimum Order Quantity (MOQ) and production lead time for wholesale orders?

For standard catalog models, our MOQ starts at 10 to 50 units per frame size, allowing distributors to evaluate market demand with low initial investment. Customized OEM orders typically require an MOQ of 100 to 300 units depending on the customization level. Standard production lead times range from 15 to 25 business days, with fast-track options available for urgent project demands.