B Curve MCBs for Standard Circuits & Fast Fault Protection

B Curve MCBs are miniature circuit breakers designed for circuits with low inrush current and predictable load behaviour. They are widely used on lighting, socket, and other standard final circuits where fast overcurrent protection is needed without accommodating heavy start-up surges.

Often referred to as Type B MCBs or B curve circuit breakers, these devices are the go-to choice for many domestic and light commercial board layouts.

B curve devices are chosen where the connected load does not create large inrush currents during normal operation. That makes them a strong fit for many everyday installations, especially in homes, smaller commercial units, and consumer unit upgrades where the correct tripping characteristic matters.

• B curve tripping characteristic – trips at around 3 to 5 times rated current
• Ideal for standard circuits – lighting, sockets, and general-purpose final circuits
• Available in multiple current ratings – including common domestic sizes such as B6, B10, B16, B20 and B32
• 6kA and 10kA options – choose to suit the installation fault level
• DIN-rail format – practical for consumer units and distribution boards

Need a different tripping characteristic? Browse our C Curve MCBs, wider MCB range, or full circuit protection collection. For delivery and returns, see our delivery information and returns policy.