{"id":3117,"date":"2026-07-28T06:11:46","date_gmt":"2026-07-28T06:11:46","guid":{"rendered":"https:\/\/chac-electric.com\/?post_type=product&p=3117"},"modified":"2026-09-07T09:33:42","modified_gmt":"2026-09-07T09:33:42","slug":"cqb2-125-miniature-circuit-breaker","status":"publish","type":"product","link":"https:\/\/chac-electric.com\/de\/product\/cqb2-125-miniature-circuit-breaker\/","title":{"rendered":"CQB2-125 Miniature Circuit Breaker"},"content":{"rendered":"

Product Overview<\/h2>\n

The CQB2-125 is an AC miniature circuit breaker<\/a> designed for overload and short-circuit protection in higher-current low-voltage distribution circuits. It is available in 63A, 80A, 100A and 125A ratings, with 1P, 2P, 3P and 4P configurations for AC 230V or AC 400V systems. Its compact modular format makes it suitable for distribution equipment where the project requires more current capacity than a conventional 63A MCB range.<\/p>\n

The series offers C and D tripping curves, an ultimate short-circuit breaking capacity (Icu) of 10,000A and a rated service short-circuit breaking capacity (Ics) of 7,500A. It is designed to IEC 60947-2 and GB\/T 14048.2, with CCC certification confirmed for the listed product. Breaking capacity, current rating and conductor selection must always be checked against the prospective short-circuit current, installation conditions and applicable local rules.<\/p>\n

How the CQB2-125 Protects a Circuit<\/h2>\n

Thermal-magnetic operation provides two complementary forms of protection. The thermal element responds to sustained overloads, while the magnetic element responds more quickly to high fault current. The breaker can also provide circuit isolation and infrequent switching within its stated application. It does not provide residual-current protection; projects that require earth-leakage protection should use a suitable RCD or RCBO in accordance with the system design.<\/p>\n

How to Select the Right CQB2-125 Configuration<\/h2>\n

Rated Current and Conductor Coordination<\/h3>\n

Choose 63A, 80A, 100A or 125A only after checking the design current, conductor capacity, ambient conditions and upstream\/downstream protection. The product reference table pairs 63A with 16mm\u00b2 copper, 80A with 25mm\u00b2, 100A with 35mm\u00b2 and 125A with 50mm\u00b2. These values are product references rather than universal cable-sizing rules; the final conductor size must be determined by the project designer or installer.<\/p>\n

Number of Poles<\/h3>\n

Select 1P, 2P, 3P or 4P according to the circuit arrangement and the conductors that must be switched or protected. Do not choose the pole configuration from the load current alone. Earthing system, neutral treatment and local installation rules also need to be considered.<\/p>\n

C Curve or D Curve<\/h3>\n

C and D curves differ in how they respond to short-duration inrush current. C curve is commonly considered for general distribution loads with moderate inrush, while D curve may be evaluated for loads with higher starting current. These are selection tendencies, not universal assignments. Review the load profile and coordination study before specifying a curve; the MCB tripping-curve guide<\/a> explains the decision in more detail.<\/p>\n

10kA Breaking Capacity<\/h3>\n

A 10kA MCB should be selected because the calculated prospective short-circuit current at the installation point is within the breaker’s verified duty\u2014not simply because 10kA is higher than 6kA. For a practical comparison, see the guide to 6kA versus 10kA MCB breaking capacity<\/a>.<\/p>\n

Typical Applications<\/h2>\n

The CQB2-125 can be evaluated for feeder and higher-current branch protection in commercial buildings, high-rise distribution systems, light-industrial facilities, infrastructure projects and other AC low-voltage distribution equipment. Suitability depends on the complete protection design, including fault level, discrimination or selectivity, conductor rating and enclosure conditions.<\/p>\n

For circuits at 63A and below, compare the more compact CQB2-63 miniature circuit breaker<\/a>. If the project requires adjustable protection settings, a higher breaking duty or additional coordination capability, review the available moulded case circuit breaker<\/a> range instead of assuming a 125A MCB is the best fit.<\/p>\n

Product Features<\/h2>\n