The Schneider Electric LRD21 is a TeSys Deca thermal overload relay rated for 12 to 18 A with Class 10A tripping per IEC 60947-4-1. Designed for motor protection, it mounts directly below TeSys D contactors (LC1D18 to LC1D38) and operates on both AC and DC networks up to 690 V at frequencies from 0 to 400 Hz.

Technical specifications:

• Commercial reference: LRD21
• Manufacturer: Schneider Electric
• EAN: 3389110346831
• Series / range: TeSys Deca (TeSys LRD)
• Product type: Thermal overload relay
• Application: Motor protection
• Network type: AC / DC
• Tripping class: Class 10A per IEC 60947-4-1
• Thermal overload setting: 12…18 A
• Rated voltage [Ue]: 690 V AC, 0…400 Hz (power circuit, IEC 60947-4-1)
• Rated insulation voltage [Ui]: 690 V (IEC) / 600 V (UL, CSA)
• Rated impulse withstand voltage [Uimp]: 6 kV
• Tripping threshold: 1.14 +/- 0.06 Ir per IEC 60947-4-1
• Phase loss sensitivity: trips at 130% of Ir in two phases, last phase at 0
• Auxiliary contacts: 1 NO + 1 NC
• Permissible thermal current [Ith]: 5 A (signal circuit)
• Compatible contactors: LC1D18, LC1D25, LC1D32, LC1D38
• Connection – power circuit: screw terminals, 1 cable 1…6 mm solid / 1.5…10 mm flexible
• Connection – control circuit: screw terminals, 2 cables 1…2.5 mm
• Tightening torque – power circuit: 2.5 N.m
• Tightening torque – control circuit: 1.7 N.m
• Dimensions (W x H x D): 45 x 66 x 70 mm
• Weight: 0.124 kg
• IP protection: IP20 per IEC 60529
• Operating temperature: -20…60 C
• Storage temperature: -60…70 C
• Dielectric strength: 1.89 kV at 50 Hz per IEC 60947-1
• Flame resistance: V1 per UL 94
• Vibration resistance: 6 Gn per IEC 60068-2-6
• Shock resistance: 15 Gn for 11 ms per IEC 60068-2-7
• Mounting: Below contactor, DIN rail, or panel (with accessories)
• Standards: EN/IEC 60947-4-1, EN/IEC 60947-5-1, UL 60947-4-1, CSA C22.2 No 60947-4-1, GB/T 14048.4, EN 50495
• Certifications: IEC, UL, CSA, CCC, EAC, BV, RINA, DNV-GL, LROS, ATEX INERIS, UKCA

Features and benefits:

• Class 10A tripping curve protects motors against sustained overload conditions per IEC 60947-4-1
• Integrated phase loss sensitivity trips at 130% of Ir when one phase is lost, preventing motor burnout
• Temperature compensation across -20…60 C ensures consistent and accurate tripping in variable environments
• Mounts directly below TeSys D contactors (LC1D18 to LC1D38) for compact motor starter assemblies
• Red stop button and blue reset button provide local manual control without additional accessories

Applications:

• Industrial motor starter panels combined with TeSys D contactors
• Pump and fan motor protection in building services and HVAC systems
• Conveyor and process machinery overload protection
• Hazardous area motor installations (ATEX INERIS certified)
• Marine and offshore motor control systems (DNV-GL, RINA, LROS certified)

Compliant with EN/IEC 60947-4-1 and EN/IEC 60947-5-1. Part of the Schneider Electric TeSys Deca range.

Also known as: Schneider LRD21, Schneider Electric LRD21, TeSys thermal overload relay 12-18A, motor protection relay LRD21.