Building-site distribution boards pose a number of challenges for constructors:

  1. Frequency-controlled equipment that may generate smooth DC residual currents in the event of a fault is used on construction sites.
  2. Building-site distribution boards are exposed to extreme weather conditions and mechanical stresses.
  3. In winter, building-site distribution boards are left unused for weeks without a power supply and usually in unheated warehouses.

Our DFS 4 B SK HD construction site power switch is perfectly equipped to meet these challenges: as a Type B AC-DC sensitive component, it reliably detects pulsating and AC residual currents, residual currents with mixed frequencies and smooth DC residual currents. Switches with tripping characteristic curve SK respond less sensitively to operation-related leakage currents, e.g. those caused by cranes.
This lower response sensitivity at high frequencies increases the availability of the equipment significantly. The HD design ensures the residual current circuit-breaker is well protected and works reliably, even if there are adverse conditions such as cold, heat, extreme temperature fluctuations, dust and the presence of corrosive gases.
The self-protection feature of the HD residual current circuit-breaker is a fundamental part of its design and is therefore permanently available: 24 hours per day, 7 days per week, 365 days per year – and even when there is no power supply.