Siemens 3RU1126-4BD0 Thermal Overload Relay

Product Description

The SIEMENS 3RU1126-4BD0 is a thermal overload relay designed to protect three-phase motors and electrical loads from damage caused by sustained overcurrent conditions. The relay monitors current draw and trips the circuit when heat buildup from excess load exceeds safe operating thresholds. It mounts directly onto compatible contactor assemblies or can be installed in a panel configuration, making it a practical choice for motor branch circuit protection in industrial and commercial electrical systems. Licensed electricians and industrial maintenance technicians are the primary installers of this device.

This thermal overload relay is suited for motor protection applications in commercial and industrial environments, including conveyor systems, pump controls, compressor circuits, and HVAC drive panels. It fits into motor control center builds and standalone starter assemblies where reliable, automatic overload protection is required. The 3RU1126-4BD0 is appropriate for new installation work and as a direct replacement in existing Siemens motor control assemblies.

Key Features

• Thermal overload protection guards motors against sustained overcurrent and heat damage
• Direct contactor-mount design simplifies integration into motor starter assemblies
• Compact form factor suitable for panel and motor control center installations
• Manual and automatic reset options common to this relay family support flexible control strategies
• Lightweight construction at 0.399 pounds minimizes added load on contactor mounting points

Compatibility

Designed as an OEM-style replacement or new-installation thermal overload relay for use in compatible Siemens motor starter and contactor assemblies. Verify contactor frame size and current range against the 3RU1126-4BD0 datasheet before installation.

Installation Notes

Installation should be performed by a qualified electrician in accordance with NEC Article 430 governing motor branch circuit and overload protection. De-energize and lock out the circuit per LOTO procedures before handling or mounting the relay. Confirm the relay current setting matches the full-load amperage rating of the motor being protected. Do not bypass or manually hold the relay in the closed position during normal operation.

Technical Specifications

• Weight: 0.399 pounds
• Length: 4.016 inches
• Width: 1.929 inches
• Height: 4.016 inches
• UPC: 75455441207

Standard Information

• Brand: SIEMENS
• Manufacturer Part Number: 3RU1126-4BD0