Schneider Electric LRD14 — Thermal Overload Relay Selection Guide

By Abdullah Zahid
16 min read
Schneider Electric LRD14 TeSys Deca thermal overload relay 7 to 10A three-phase motor protection relay

Schneider Electric LRD14 TeSys Deca Thermal Overload Relay — 7 to 10 A Motor Protection with Phase Unbalance Detection

Controls engineers and procurement specialists searching for the Schneider Electric LRD14 are typically at one of two decision points: replacing a failed overload relay in an existing TeSys D motor starter, or specifying motor protection for a new 3–4 kW three-phase load in a multi-motor control panel. Either way, the purchase decision hinges on three things — confirming the 7 to 10 A current range covers the motor's full-load current, verifying voltage and frequency compatibility, and knowing the part is in stock. The LRD14 is a 3-pole thermal overload relay rated 690V AC with integrated phase unbalance detection, manual-automatic reset, and a compact 70 mm x 45 mm footprint that mounts directly onto TeSys D contactors or standalone on DIN rail.

If you have already confirmed this is the right part, check current pricing and availability for the LRD14 at LeadTime.ca — we ship worldwide.

Who Should Buy the LRD14 — and Who Shouldn't

The Schneider Electric LRD14 is the right choice when all of the following apply to your application:

  • Your motor's full-load current (FLC) falls within the 7 to 10 A adjustment range — confirmed from the motor nameplate, not estimated
  • Your power circuit operates at 690V AC or 600V AC, with a frequency within the 0–400 Hz rated range
  • You need a 1NC-1NO contact configuration for motor circuit protection and status signalling to a PLC or alarm circuit
  • You are mounting directly onto a TeSys D contactor or onto standard DIN rail in a control panel rated IP20 or better
  • Your application does not require remote monitoring, predictive maintenance data, or electronic reset capability — this is a thermal relay, not a smart relay
  • Class 10A trip curve is acceptable; your process can tolerate a standard IEC-defined thermal trip response rather than a class 20A slower-trip profile

If your motor FLC exceeds 10 A, the LRD14 is not the correct part. The LRD16 covers 16–24 A and the LRD22 covers 22–32 A — check the variant comparison table below before ordering.

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What the LRD14 Does in a Motor Control System

The Schneider Electric LRD14 is a 3-pole thermal overload relay from the TeSys Deca series. Its job is straightforward and critical: monitor the current drawn by a three-phase AC motor and interrupt the motor circuit before sustained overcurrent causes winding damage. Unlike fuses or circuit breakers — which respond to instantaneous faults — the LRD14 uses bimetallic thermal sensing to respond to sustained overcurrent conditions that build up over time, the kind that cause motor coil burnout without triggering upstream protection devices.

The class 10A trip curve defines the relay's thermal response characteristic per IEC 60947-4-1. This means the relay will trip within a defined time window when current exceeds the dial setting — long enough to ride through normal motor starting inrush, short enough to protect against locked-rotor and sustained overload conditions. The integrated phase unbalance detection is a separate protection function that specifically monitors three-phase balance. If one phase is lost or severely degraded, the relay trips before the motor attempts to run single-phase — a condition that causes rapid and catastrophic winding failure in three-phase motors.

Manual-automatic reset is standard on the LRD14. In manual mode, an operator must press the reset button on the relay face after a thermal trip — a safety feature that forces human acknowledgment before restart. In automatic reset mode, the relay re-engages after the bimetal cools, allowing automatic restart for remote or unattended installations. The 1NC-1NO contact output gives the control circuit two independently usable switching signals: the normally closed contact for hardwired safety loops, and the normally open contact for PLC digital inputs or status lamps.

Typical System Architecture for the LRD14

The LRD14 sits between the motor contactor and the motor terminals in the power circuit, acting as the final current-sensing protection element before power reaches the motor leads.

  • Upstream: Three-phase supply through main disconnect, fusing or MCCB rated for branch circuit protection
  • Contactor stage: TeSys D series contactor switching the motor on and off under control circuit command
  • LRD14 overload relay: Mounted directly on the TeSys D contactor (contactor-mount configuration) or separately on DIN rail; monitors current on all three phases simultaneously
  • Motor terminals: LRD14 output terminals connect directly to motor input leads for the protected load
  • Control circuit: LRD14 NC contact wired into the motor control circuit (hardwired safety or PLC input); NO contact wired to status lamp or alarm input

Where the LRD14 Gets Deployed: Industries and Use Cases

The LRD14 is at home wherever a 3–4 kW three-phase motor needs reliable overcurrent and phase-loss protection inside a standard industrial control panel. Pump and fan applications are the most common — small centrifugal pumps, cooling fans on process equipment, and circulation systems where motor burnout from phase loss is a genuine operational risk. In these installations, the LRD14 is often specified alongside a TeSys D contactor to form a complete, compact direct-on-line motor starter in a single DIN-rail slot width.

OEM panel builders designing packaged machinery — conveyor systems, packaging lines, light assembly automation — rely on the LRD14 for its compact 70 mm x 45 mm footprint. When a panel contains six to twelve small motor loads, the ability to mount the overload relay directly on the contactor rather than as a separate device significantly reduces panel depth and wiring complexity. The relay's -20 to +60°C operating temperature range also makes it a valid choice for unheated machinery enclosures in northern climates and outdoor-rated control panels that see seasonal temperature extremes.

Maintenance teams managing multi-motor facilities frequently standardize on the LRD14 as the default relay for all motors in the 3–4 kW range. Holding a small quantity of LRD14 units as spare stock provides fast response to motor protection failures without the lead time uncertainty of sourcing unfamiliar parts under production pressure. Facilities with known single-phase fault history from utility grid instability particularly value the built-in phase unbalance detection, which provides automatic protection without requiring additional monitoring equipment.

Application Typical Deployment
Small pump motor protection LRD14 contactor-mounted in DOL starter; phase-loss detection protects against utility single-phase faults
OEM multi-motor control panel Multiple LRD14 units paired with TeSys D contactors; compact form reduces panel footprint for 4–6 small motor loads
HVAC fan motor starter DIN-rail standalone LRD14 protecting 3–4 kW supply air or exhaust fan; manual reset for supervised restart after trip
Retrofit motor starter replacement Direct LRD14 swap into existing TeSys D contactor slot; no panel rewiring required
Unheated outdoor enclosure LRD14 selected for -20 to +60°C operating range; installed in sealed IP54 or IP65 enclosure to meet environment requirements
Maintenance spare standardization Plant maintains LRD14 stock as standard relay for all 3–4 kW motor branches; reduces mean-time-to-repair for overload failures

LRD14 Specifications: What Engineers Need to Verify Before Ordering

Parameter Value Note
Current Adjustment Range 7–10 A Dial adjustable; class 10A trip curve per IEC 60947-4-1
Pole Count 3 Three-phase motor protection
Power Circuit Voltage 690V AC / 600V AC 0–400 Hz rated; confirm regional voltage variant with distributor
Signalling Circuit Voltage 120V AC max / 125V DC max Low-voltage contacts for PLC inputs and status lamps
Contact Form 1NC + 1NO 10 A contact rating; signalling rated 3 A @ 120V AC, 0.22 A @ 125V DC
Dimensions 70 mm L x 45 mm W Compact DIN-rail footprint; direct contactor-mount compatible
Operating Temperature -20 to +60°C Industrial range; suitable for unheated enclosures
Enclosure Rating IP20 Requires sealed panel for dusty or wet environments
Vibration / Shock 6 Gn vibration / 15 Gn shock for 11 ms Per IEC 60068-2-6 and IEC 60068-2-7
Certifications IEC 60947-4-1, UL 508, CE, ATEX 94/9, CSA C22.2 No. 14 Covers North American, European, and explosive-atmosphere applications

Full technical specifications are available on the product page at LeadTime.ca.

LRD14 vs. LRD10, LRD16, LRD22: Which Rating Do You Actually Need?

The TeSys Deca LRD series covers a wide motor current range through distinct model variants. Each model is a class 10A relay with the same contact configuration and mounting compatibility — the only variable that matters for selection is whether your motor's full-load current falls within the relay's adjustment range. Selecting a relay whose range starts above your motor FLC gives you no usable protection. Selecting one whose range ends below your motor FLC means the relay will trip under normal operating current.

Model Current Range Approx. Motor Rating @ 400V Trip Class Best Fit
LRD10 10–14 A 5–7.5 kW 10A Mid-range motors; overlaps with LRD14 upper range
LRD14 7–10 A 3–4 kW 10A Small-to-medium motors; pumps, fans, conveyors
LRD16 16–24 A 7–11 kW 10A Medium motors; larger pumps and compressors
LRD22 22–32 A 11–15 kW 10A Larger industrial drives and process motors

Note: kW estimates are at 400V three-phase at 0.85 power factor. Always verify against the motor nameplate FLC — never size by kW rating alone. If your motor FLC exceeds 10 A, the LRD14 is the wrong part: check availability of the correct LRD variant at LeadTime.ca.

Expert Verdict: Is the LRD14 the Right Relay for Your System?

The Schneider Electric LRD14 earns its place in industrial panels by doing exactly one job with no complexity and no maintenance overhead: protecting small three-phase AC motors from overcurrent and phase loss. The built-in phase unbalance detection is the feature that elevates this relay above basic thermal protection — it actively catches single-phase motor run conditions before coil damage occurs, and it does so without any external sensing hardware or control logic. For automation integrators building compact multi-motor panels, the direct contactor-mount compatibility with TeSys D contactors is a genuine panel-space advantage. For plant maintenance teams, the benefit is even more straightforward: a standard, proven relay that any qualified electrician can replace in minutes from a small spare stock.

The LRD14 has clear and honest limits. It carries no communication port, no diagnostic data output, and no remote reset capability. If your application requires predictive maintenance monitoring, current trend logging, or integration with a condition monitoring system, a thermal relay is the wrong tool regardless of brand. Electronic overload relays provide those capabilities at higher cost. Additionally, the IP20 enclosure rating means the LRD14 must be installed inside a suitably sealed panel — it is not independently suitable for washdown environments or outdoor exposure without an enclosure upgrade. If your motor FLC is above 10 A, stop here: the LRD16 (16–24 A) or LRD22 (22–32 A) are the correct variants, and ordering the LRD14 for an oversized load will result in either nuisance tripping or inadequate protection depending on how the dial is set.

From a procurement standpoint, the LRD14 is a well-supported part in the TeSys Deca family with stable availability through specialist industrial distributors. Sourcing through a distributor that carries TeSys D series inventory — rather than a general-purpose retail channel — matters for two reasons: verified stock with realistic lead times, and pre-sales technical support to confirm you have the right voltage variant, terminal type, and contactor pairing before the part ships. Check current pricing and lead time for the LRD14 at LeadTime.ca — available for order with worldwide shipping.

For volume pricing on multi-panel projects or to confirm stock before committing to a build schedule, contact the LeadTime.ca team directly — we ship worldwide.

What Engineers Need to Know Before Ordering the LRD14

Because community discussion specific to the LRD14 is sparse compared to broader PLC and drive forums, the most reliable guidance comes from application engineering experience and the documented mistakes that happen when buyers order this relay without completing a full pre-order check. The LRD14 is a precise-fit component — the current range, voltage class, terminal type, and mounting configuration all need to match the application before the purchase order is placed. The following section distills the most important pre-order knowledge for engineers who are specifying or sourcing this relay for the first time.

The most common ordering error with the LRD series is selecting a model based on estimated motor horsepower rather than reading the motor nameplate FLC directly. A 4 kW motor nameplate at a specific voltage and power factor may show a full-load current of 8.5 A — safely within LRD14 range — or it may show 10.8 A, which puts it above the 10 A dial maximum. Ordering by kW approximation without reading the nameplate is how the LRD14 ends up on a motor it cannot adequately protect. The second most frequent issue is terminal type mismatch: the LRD14 is available with screw clamp, spring clamp, ring terminal, and EverLink spring terminal configurations, and ordering the wrong terminal type against existing wiring gauge causes installation delays and sometimes forces a reorder. Verify the terminal style explicitly when placing the order.

Engineers also need to understand the class 10A trip curve in context. Class 10A means the relay will trip within a specific time envelope defined by IEC 60947-4-1 when current exceeds the set point — it is calibrated to tolerate motor starting inrush for a standard direct-on-line start without nuisance tripping. However, motors with unusually high starting loads, cyclic duty profiles, or those started through a VFD may have a different inrush profile than class 10A anticipates. For VFD-fed motors in particular, the LRD14 is designed for fixed-frequency AC circuits rated 0–400 Hz — not for the chopped waveform output of a variable frequency drive without an appropriate input filter. Confirm the power supply type before specifying this relay on a variable-speed drive application. When in doubt, LeadTime.ca's technical team can help verify the application before the order is placed.

Wiring and Installation Overview

The following overview covers key installation requirements for the LRD14. For full wiring diagrams and detailed procedures, refer to the Schneider Electric installation manual for the TeSys Deca series.

  • De-energize and lock out the panel at the main disconnect before beginning any installation; confirm zero-voltage state at the relay mounting location before handling terminals
  • Connect three-phase line input to relay input terminals and three-phase output terminals to motor leads; for contactor-mount configuration, the relay clips directly onto the TeSys D contactor face with no inter-device wiring required
  • Wire the NC contact into the motor control circuit (hardwired safety loop, emergency stop chain, or PLC digital input) and the NO contact to a status lamp or secondary PLC input as needed by your control logic
  • Set the amperage adjustment dial to the motor FLC value — recommended at 5–10% above the nameplate FLC to allow for normal load variation, but never above the 10 A dial maximum; document the dial setting on the panel label for future maintenance reference
  • Torque all screw clamp terminals to the manufacturer's specified value and verify no wire movement after initial power cycling; for EverLink terminals, confirm wire ferrules are installed and fully seated before energizing

Compatible System Components and System Expansion

The LRD14 is part of the TeSys Deca series ecosystem. The following components are directly compatible and commonly specified alongside the LRD14 in motor starter assemblies:

  • TeSys D series contactors — Direct contactor-mount configuration; LRD14 clips onto the contactor face to form a compact direct-on-line motor starter without separate DIN-rail mounting for the overload relay
  • TeSys D series auxiliary contact blocks — Add supplementary switching contacts to the contactor stack for expanded control circuit signalling
  • TeSys D series overload relay socket adapters — Enable standalone DIN-rail mounting of the LRD14 when contactor-mount installation is not required or space constraints favor separate mounting
  • LRD series terminal block adapters (screw, spring, ring, EverLink variants) — Terminal style selection must match the LRD14 ordered; verify wire gauge compatibility before installation

Wrong-Part Prevention Checklist Before You Order

Run through every item on this checklist before placing your order. Each point represents a confirmed source of ordering errors for the LRD14.

  1. Confirm motor full-load current (FLC) falls within 7–10A adjustment range; do NOT select LRD14 for motors rated above 10A continuous
  2. Verify power system voltage is 690V AC or 600V AC; LRD14 is NOT rated for 440V or 480V single voltage without confirmation of the specific model variant
  3. Check that facility power frequency is 0–400 Hz (confirms AC, not variable frequency drive output requiring special protection relay)
  4. Confirm no requirement for electronic reset or remote monitoring; LRD14 is manual-automatic thermal, not smart relay
  5. Verify contactor pairing: If using with TeSys D contactors, ensure contactor amperage matches motor FLC (do not oversize contactor)
  6. Check terminal type compatibility with existing wiring (screw clamp, spring, ring, or EverLink); verify wire gauge accepts terminal design
  7. Confirm class 10A trip curve is acceptable for application; some critical processes require class 20A (slower trip, more tolerance for inrush)
  8. Verify mounting environment IP20 is sufficient (no washdown or dust ingress risk); if harsh environment, specify sealed enclosure or higher IP rating variant

If any item on this checklist raises a question about your specific application, contact the LeadTime.ca team before ordering — our technical team can confirm the correct variant and check stock before you commit.

Frequently Asked Questions

Can I use the LRD14 on a motor controlled by a variable frequency drive?

The LRD14 is rated for fixed-frequency AC power circuits from 0–400 Hz. Variable frequency drives output a chopped waveform that is not equivalent to the sinusoidal AC this relay is calibrated for. Using the LRD14 directly on the output side of a VFD without an appropriate input filter can result in nuisance tripping or unreliable thermal sensing. For VFD-fed motors, consult the drive manufacturer's overload protection recommendations — electronic overload relays are typically the preferred solution.

What is class 10A and does the LRD14 have the right trip curve for my application?

Class 10A is an IEC 60947-4-1 designation that defines the relay's thermal trip response time relative to a multiple of the set current. It is calibrated to tolerate the starting inrush of standard direct-on-line AC motors without tripping during normal startup while still protecting against sustained overload. Class 10A is correct for most general-purpose motors. Applications with unusually high starting torque requirements or long acceleration ramps may need class 20A — a slower trip profile that tolerates more inrush time. Confirm the load profile before specifying the LRD14 for high-inrush duty.

What is the difference between manual and automatic reset on the LRD14, and which should I use?

In manual reset mode, the relay latches in the tripped state after an overcurrent event and requires an operator to physically press the reset button before the motor can restart. This is the safer default for most applications because it forces human review of the fault condition before restart. Automatic reset mode allows the relay to re-engage after the bimetal element cools, enabling automatic motor restart without operator intervention. Automatic reset is appropriate only for remote or unattended installations where process continuity is prioritized and automatic restart is safe — verify this with your facility's safety requirements before enabling automatic mode.

How do I know if the LRD14 has tripped versus a contactor fault or upstream breaker?

The LRD14's 1NC-1NO contact output changes state when the relay trips. If the NC contact is wired into your motor control circuit, the motor circuit will open and the motor will stop. If the NO contact is wired to a PLC input or status lamp, that input will activate during a trip condition. On the relay body itself, a visual trip indicator (flag or button position change) confirms the tripped state. If the motor stops but the LRD14 shows no trip indication, investigate upstream protection devices — the relay has not operated.

Is the LRD14 a direct replacement for an older TeSys D overload relay in an existing panel?

The LRD14 is part of the TeSys Deca series and is designed to be directly compatible with TeSys D contactors using the same mechanical mounting interface. If the existing relay occupies the same contactor-mount slot and falls within the 7–10 A range, the LRD14 is a direct retrofit candidate. Verify the terminal type of the existing installation matches the LRD14 variant you are ordering — screw clamp, spring clamp, and EverLink are not interchangeable without re-terminating wiring.

Does the LRD14 carry both UL 508 and CSA C22.2 No. 14 certification for North American installations?

Yes. The LRD14 carries UL 508 certification for US industrial control equipment and CSA C22.2 No. 14 certification for Canadian electrical safety requirements. It also carries CE marking for European conformity and ATEX 94/9 certification for explosive atmosphere applications where applicable. These certifications make it a valid specification choice for North American industrial installations without requiring additional compliance verification, provided the installation meets IP and environmental requirements for the specific location.

Why Order the LRD14 from LeadTime.ca

  • LeadTime.ca maintains inventory of TeSys Deca series components with worldwide shipping — not limited to any single region or country
  • Pre-sales technical support is available to verify current adjustment range, terminal type, and contactor compatibility before your order ships
  • Volume pricing is available for multi-panel builds and OEM procurement — contact the team directly for project-quantity quotes
  • Sourcing through a specialist industrial distributor reduces the risk of receiving incorrect variants, incompatible terminal styles, or uncertified product that creates compliance issues on inspection

LRD14 At-a-Glance Summary

  • Current adjustment range: 7–10 A dial-adjustable; class 10A trip curve per IEC 60947-4-1
  • Rated voltage: 690V AC and 600V AC power circuit; frequency range 0–400 Hz
  • Contact output: 1NC + 1NO, 10 A contact rating; signalling rated 3 A @ 120V AC and 0.22 A @ 125V DC
  • Dimensions: 70 mm x 45 mm compact footprint; direct contactor-mount or standalone DIN-rail
  • Operating temperature: -20 to +60°C; storage to +80°C
  • Enclosure rating: IP20 — requires sealed panel for wet or dusty environments
  • Vibration tolerance: 6 Gn per IEC 60068-2-6; shock tolerance: 15 Gn for 11 ms per IEC 60068-2-7
  • Certifications: IEC 60947-4-1, UL 508, CE, ATEX 94/9, CSA C22.2 No. 14, RoHS compliant
  • Phase unbalance detection: integrated; trips on phase loss before motor single-phases
  • Correct for motors approximately 3–4 kW at 400V three-phase; use LRD16 or LRD22 for larger loads

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