Siemens HE43B020U Three Phase Circuit Breaker

Siemens HE43B020U is a three‑pole molded‑case circuit breaker rated for 20 A at 480 V, designed to protect three‑phase feeders in industrial panels and distribution gear. It belongs to Siemens' HED/HE family of low‑voltage MCCBs and provides thermal‑magnetic trip protection for branch circuits, with an interrupt rating of 42 kA at 480 V in standard configurations. The 3P device is intended for 480 V AC systems and is commonly used to guard motor circuits and other three‑phase loads in commercial or light‑industrial installations that rely on Siemens panel boards. This model is cataloged under multiple part numbers (including HED43B020 and HE43B020U), reflecting its place in the Siemens lineup and its availability from distributors such as Grainger, BayPower, and Santa Clara Systems.