LRE357 | Easy TeSys differential thermal overload relay 37…50 A – class 10A – Schneider Electric

Name: Schneider Electric LRE357 Thermal Overload Relay 37-50A
Brand: Schneider Electric
SKU: LRE357
Price: 3431.40 INR
Availability: InStock

SKU: LRE357

Original price was: ₹8,170.00.Current price is: ₹3,431.40. Excl. GST

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The Schneider Electric LRE357 is an overload relay from the Easy TeSys range, engineered for motor control and switching in demanding Indian and international installations. Key ratings include 37–50 A, <= 690 V AC, IP20. Buy the LRE357 | Easy TeSys differential thermal overload relay 37...50 A - class 10A online at myelectric.in with GST invoice, genuine-product assurance, and fast delivery across India — bulk and worldwide export enquiries welcome.

📋 Technical Specifications

Product
Brand	Schneider Electric
Part Number / SKU	LRE357
Category	Overload Relay
Main
Range	Easy TeSys
Range of product	Easy TeSys Protect
Product or component type	Differential thermal overload relay
Device short name	LRE
Relay application	Motor protection
Phase failure sensitivity	Tripping current 130 % of Ir on two phase, the last one at 0 conforming to IEC 60947-4-1
Complementary
Product compatibility	LC1E50…95
Network type	AC
Network frequency	50…60 Hz
Mounting support	Under contactor Plate, with specific accessories Rail, with specific accessories
Thermal overload class	Class 10A conforming to IEC 60947-4-1
Signalling function	Relay trip indicator
Thermal protection adjustment range	37…50 A
Tripping threshold	1.14 +/- 0.06 Ir conforming to IEC 60947-4-1
Mechanical robustness	Shocks: 6 Gn for 11 ms conforming to IEC 60068-2-7 Vibrations: 3 GN conforming to IEC 60068-2-6
Auxiliary contact composition	1 NO + 1 NC
[Ith] conventional free air thermal current	5 A for signalling circuit
[Ue] rated operational voltage	<= 690 V AC
Associated fuse rating	100 A gG for power circuit 63 A aM for power circuit 5 A gG for signalling circuit
[Ui] rated insulation voltage	690 V conforming to IEC 60947-4-1
[Uimp] rated impulse withstand voltage	6 kV
Local signalling	Trip indicator
Control type	Push-button red stop: Push-button green reset:
Temperature compensation	-20…60 °C
Connections – terminals	Signalling circuit: screw clamp terminals 2 1…2.5 mm² – cable stiffness: flexible without cable end Signalling circuit: screw clamp terminals 2 1…2.5 mm² – cable stiffness: flexible with cable end Signalling circuit: screw clamp terminals 2 1…2.5 mm² – cable stiffness: solid without cable end Power circuit: screw clamp terminals 1 4…35 mm² – cable stiffness: flexible without cable end Power circuit: screw clamp terminals 1 4…35 mm² – cable stiffness: flexible with cable end Power circuit: screw clamp terminals 1 4…35 mm² – cable stiffness: solid without cable end
Recommended tightening torque	Power circuit: 9 N.m – on screw clamp terminals Signalling circuit: 1.7 N.m – on screw clamp terminals
Height	54 mm
Width	70 mm
Depth	113 mm
Product weight	0.46 kg
Environment
Standards	EN/IEC 60947-1 EN/IEC 60947-5-1 EN/IEC 60947-4-1 GB/T 14048.1 GB/T 14048.4 GB/T 14048.5 EN/IEC 60335-1:Clause 30.2 EN/IEC 60335-2-40:Annex JJ
Product certifications	CB Scheme CCC CE EAC
Protective treatment	TH conforming to IEC 60068
IP degree of protection	IP20 conforming to IEC 60529
Ambient air temperature for operation	-20…60 °C without derating conforming to IEC 60947-4-1 -20…70 °C with derating
Ambient air temperature for storage	-60…80 °C
Fire resistance	850 °C conforming to IEC 60068-2-1
Dielectric strength	6 kV at 50 Hz conforming to IEC 60255-5
Electromagnetic compatibility	Surge withstand: 6 kV conforming to IEC 60801-5
Packing Units
Unit Type of Package 1	PCE
Number of Units in Package 1	1
Package 1 Height	8 cm
Package 1 Width	9 cm
Package 1 Length	12.5 cm
Package 1 Weight	484 g
Unit Type of Package 2	S02
Number of Units in Package 2	9
Package 2 Height	15 cm
Package 2 Width	30 cm
Package 2 Length	40 cm
Package 2 Weight	4.742 kg
Contractual warranty
Warranty (in months)	18

⚡ Key Features

Adjustable current range 37–50 A — set to the motor nameplate FLC for accurate overload detection; range covers multiple motor sizes from a single relay model.
Class 10A trip class — trips within 10 seconds at 7.2× FLC; standard for normal-start motors (fans, pumps, compressors) where starting time is under 10 seconds.
Bimetal thermal element with phase-loss sensitivity — independently monitors each phase; trips if any phase carries more than ~115% of the set current, or on complete phase failure.
Normally open (NO) and normally closed (NC) auxiliary contacts built in — NO contact wired to motor run indicator; NC contact wired to PLC fault input or motor starter stop circuit.
Direct clip-on mounting to TeSys LC1 contactors — no external wiring between overload and contactor; forms a complete IEC 60947-4-1 DOL motor starter combination.
Manual/automatic reset selectable — set to manual for attended machinery requiring operator acknowledgement; auto-reset for unattended remote installations.
Manufactured to IEC 60947-4-1 / IS 13947-4-1 — complies with the applicable Indian BIS and IEC international standards for this product category.
BIS certified, CE marked, RoHS compliant — meets Indian regulatory requirements for use in government, commercial, and industrial electrical installations.
Genuine authorised Schneider Electric product — sourced directly from the official distribution network with full manufacturer traceability and warranty.
GST invoice provided for India orders — valid for corporate procurement, government project orders, and public tender supply via myelectric.in.

❓ Frequently Asked Questions

Q: How do I set the 37–50 A adjustable range on the LRE357 for my motor?

A: Turn the setting dial to the motor’s nameplate full-load current (FLC) — the FLC must fall within the 37–50 A range of this device. Setting it at the motor FLC (not the maximum of the range) gives correct overload trip timing while still riding through normal starting inrush. If the motor FLC is outside this range, select the adjacent rating in the same series.

Q: How do I set the LRE357 to protect a motor without causing nuisance trips on starting?

A: Set the thermal overload dial to the motor’s nameplate full-load current (FLC) — ensure the FLC is within the 37–50 A range of this relay. For star-delta starters, set the overload relay to 58% of motor FLC (line current in delta = FLC × 0.58). Allow 10 trips for the relay’s thermal memory to stabilise before adjusting the setting.

Q: Does the LRE357 provide single-phase (phase loss) protection?

A: Schneider Electric thermal overload relays include single-phase sensitivity: if one phase is lost, the remaining phases carry higher current, causing the bimetal to heat and trip within the specified time. For critical motors, add a dedicated phase-loss relay for faster response independent of load — overload relay phase-loss protection is load-dependent and may take minutes to trip at light load.

Q: What is the difference between an Overload Relay and a standard MCB — and why use the LRE357?

A: A standard MCB protects against overload and short-circuit only. An Overload Relay provides thermal overload protection calibrated to motor FLC, protecting the motor from sustained overloads that would destroy windings before a standard MCB trips. Choose the LRE357 when the application specifically requires overload relay characteristics.