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MCCB Supplier & Distributor- AT&T GB

Understanding MCCBs and MCBs: Technical Differences and Leading Brands

Circuit breakers are critical components in modern electrical distribution, protecting circuits from overloads and short circuits. While both Miniature Circuit Breakers (MCBs) and Molded Case Circuit Breakers (MCCBs) fulfill this primary safety function, they are engineered for distinctly different load demands, system scales, and operational environments.

Key Technical Differences

The primary distinction between an MCB and an MCCB lies in current capacity, trip settings, and breaking capacity:

  • Current Rating: MCBs are designed for low-current applications, typically rated up to 100A (or 125A max). In contrast, MCCBs handle much higher electrical loads, ranging from 15A up to 2,500A.

  • Trip Setting Adjustability: MCBs feature fixed thermal and magnetic trip characteristics set during manufacturing. MCCBs often offer adjustable trip settings (for both overload and short-circuit protection), allowing tailored configuration for complex commercial or industrial loads.

  • Breaking Capacity: MCBs generally offer lower interrupting capacities (typically 3kA to 15kA), making them ideal for residential and light commercial sub-circuits. MCCBs provide significantly higher breaking capacity (10kA up to 200kA), enabling them to safely interrupt high prospective fault currents.

  • Physical Mounting: MCBs mount onto standard DIN rails in consumer units, whereas larger MCCBs require dedicated enclosure space and direct panel or busbar mounting.

Leading Manufacturers

The market features several world-renowned manufacturers producing high-specification MCBs and MCCBs:

  • Schneider Electric (ComPact & Acti9 series)

  • ABB (SACE & System pro M series)

  • Siemens (3VA & SENTRON series)

  • Eaton (NZM & Moeller series)

  • Hager

  • Legrand

Sourcing Quality Circuit Protection

When procuring circuit protection for commercial installations, partnering with an experienced MCCB supplier ensures compliance and reliability. AT&T GB Ltd is a leading electrical distributor in the UK, maintaining extensive stock of MCCBs and MCBs from all major manufacturers to meet immediate project demands for electrical contractors.

All Major Electrical Brands in Stock
Electrical Product Ranges
We support companies requiring electrical products and services in whatever market sector they operate. We know the needs of a facilities management company differ greatly from those of a commercial electrical contractor or a domestic installer. That’s why we keep large stock holdings and why our sales teams, processes and logistics are set up to respond to whatever your business needs. 
That’s why we keep large stock holdings and why our sales teams, processes and logistics are set up to respond to whatever your business needs. 

MCCB & MCB supplier for electrical contractors

AT&T GB are authorised Electrical Distributors

AT&T GB Ltd Electrical Wholesaler in London
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