Schneider Electric B3.70 Thermal Overload Relay

The Schneider Electric Square D B3.70 Thermal Overload Relay Heater Element Unit is a plug‑in heater element for Square D Type B and Type S overload relay frames that provides motor overload protection by converting motor current into heat and triggering a time‑delayed thermal trip via a melting alloy or bimetal sensing element. It carries a full‑load current range of 2.62–2.99 A (for SuperBreakers) and uses a Class 20 thermal protection system to respond to sustained overload conditions. Built to fit standard Square D motor control configurations, the heater element mounts directly into the overload relay base and works within industrial motor control systems and MCC assemblies to protect conveyors, pumps, compressors, HVAC equipment, and manufacturing machinery. Its compatibility with Square D Type B / Type S frames helps maintain consistent protection across compatible equipment, and the unit is commonly referenced alongside related replacements such as the Square D B3.71 Thermal Heater Element, Schneider Electric LRD Series Thermal Units, and Siemens 3RU11 Thermal Overload Heater Elements.