Miniature circuit breaker for operation in buildings
Siemens has developed a new miniature circuit breaker (MCB) with a switching capacity of 10 kilo amperes (kA), which can be used especially in non-residential and industrial buildings. The 5SL4 miniature circuit breaker safely shuts down circuits in buildings in case of overloads or short circuits and thus protects cables and devices from damage. The MCB with an integrated snap-on fixing system for mounting on the standard mounting rail can be integrated with minimum effort in existing electrical installations and combined with additional devices.
The MCB is compatible with all Siemens accessory components, such as AFD units, auxiliary and residual current operated circuit breakers, undervoltage releases and fault signal contacts, and can thus be expanded by a wide range of functions. In addition to high operational and plant safety, the 5SL4 miniature circuit breakers offer protection and convenience during installation and servicing:
The touch protection integrated in the terminals protects the installer from electrical shock when connecting the devices.
Siemens
+49 (69) 797 6660*
Recommended Reading

Is 2026 the year electricians can no longer afford to stand still?
Logic4training’s Mark Krull asks whether 2026 is the year electricians must expand their skills or risk being left behind.

If AI is compromised, what fails next in critical energy operations?
Kiteworks’ Dario Perfettibile looks at how AI compromise could ripple through energy operations, from detection failures to physical disruption.

Can smart buildings take the heat off an overstretched grid?
As grids strain under peak demand, Parity CEO Brad Pilgrim makes the case for smart HVAC as a practical route to flexibility and resilience.
