Technical Analysis and Application Guide for Siemens EG Frame Molded Case Circuit Breaker NEB/HEB Series

AC control voltage range DC control voltage range

24V 24V

48 – 60V —

110 – 127V —

208 – 240V —

380 – 500V —

525 – 600V —

— 48 – 60V

— 110 – 125V

— 220 – 250V

5. Rules and combinations for accessory installation

Left accessory slot: Only shunt release or undervoltage release can be installed (applicable to 3-pole circuit breakers).

Right accessory slot: Only auxiliary switches and/or alarm switches can be installed (applicable to 2-pole and 3-pole circuit breakers).

Maximum configuration example:

Left side: 1 shunt release or undervoltage release

Right side: Up to 2 sets of auxiliary contacts (2A – 2B) or 1 set of alarm contacts (1A – 1B)

Installation and System Integration Guide

The EG frame circuit breaker adopts a low plug version design, optimized for panel board installation, with a compact structure and space saving. Attention should be paid during installation:

Thermal compatibility and environmental adaptability: All electrical parameters are based on a 40 ° C environment, and capacity reduction needs to be considered in high-temperature environments.

Wiring specifications: Strictly tighten the wiring terminals according to torque requirements, use designated connector kits to avoid overheating caused by poor contact.

Installation sequence of accessories: First install the left release accessories, then install the right signal accessories to ensure accurate module docking.

System coordination: In selective protection systems, coordination settings should be made based on the breaking capacity and time current characteristics of the upper and lower circuit breakers.

Application scenarios and selection suggestions

Commercial building power distribution: The NEB series is suitable for protecting lighting, sockets, and air conditioning circuits.

Industrial control system: HEB series is suitable for motor control center and distribution cabinet incoming line protection.

Key power system: equipped with shunt release, undervoltage release, and alarm switch to achieve remote monitoring and fault protection.

Renewable energy system: suitable for DC side protection of photovoltaic distribution boxes and energy storage systems (pay attention to DC voltage rating).