Siemens 5SP3840-2 SENTRON — 40 A Class E Main MCB for Meter Panels
The Siemens 5SP3840-2 is a 3-pole main miniature circuit breaker from the SENTRON 5SP3 series, rated at 40 A with a Class E tripping characteristic and a 25 kA breaking capacity per EN 60898. It is designed for 400 V AC, 50 Hz supply systems and mounts on a 40-mm busbar system per DIN 43870 Part 2, making it the standard incoming protective device for residential and infrastructure meter panels. The Class E characteristic is a Siemens-specific curve, tuned for main distribution in meter-panel applications where coordination with downstream MCBs is required.
Mounting and Integration — Busbar-Meter Panel Fit
Mounts directly on a 40-mm busbar system in compliance with DIN 43870 Part 2, the standard for German-style meter panels. The 4.5 width units (each ~18 mm) occupy 81 mm of busbar space. Depth of 89.5 mm with a 76.3 mm enclosure depth — verify clearance to the meter-panel cover, especially if a locking slide or wire seal is fitted. Infeed is via the box terminal at the bottom of the unit; outgoing feeder uses a spring-loaded terminal. Conductors from 2.5 mm² up to 50 mm² solid or stranded are accepted, covering the full range from 6 mm² meter tails to 35 mm² main feeders. The unit is sealable via a locking slide with lock, additional wire seal, cable ties, or Antilux — meeting utility metering requirements for tamper-proofing.
Protection class IP40 with connected conductors installed. Overvoltage category IV, surge voltage resistance 6 kV, insulation voltage 690 V. Shock resistance 30 g (3 impacts, 11 ms duration) and vibration resistance 2 g per IEC 60068-2-6 (20 frequency cycles, 5 to 150 Hz).