Schneider Electric LRD16 — TeSys Deca Overload Relay Buying Guide

By Abdullah Zahid
15 min read
Schneider Electric LRD16 TeSys Deca thermal overload relay for three-phase motor protection in industrial motor starter assemblies

Schneider Electric LRD16 TeSys Deca Thermal Overload Relay — Specifications, Compatibility and Selection Guide

If you are specifying motor protection for a three-phase motor with a full-load amperage between 9 and 13A, the Schneider Electric LRD16 is likely the exact part you need. This TeSys Deca thermal overload relay delivers Class 10A trip protection, direct-mount compatibility with the full TeSys D contactor range from LC1D09 through LC1D38, built-in phase-loss sensitivity, and field-selectable manual or automatic reset — all in a 70 x 45 x 66mm bimetallic package rated for 600V and 690VAC across 0 to 400Hz. Confirming your motor nameplate FLA is the one non-negotiable step before ordering.

If you have already confirmed this is the right part, check current pricing and availability for the LRD16 at LeadTime.ca — ships worldwide.

Is the LRD16 the Right Relay for Your Motor?

The LRD16 is the correct choice for engineers and procurement specialists sourcing thermal overload protection for three-phase AC motors whose nameplate FLA falls between 9 and 13A. It is a direct, proven fit for TeSys D motor starter assemblies and standalone installations alike.

  • Motor nameplate full-load amperage is between 9A and 13A — this is the fixed, non-negotiable constraint
  • Power supply is three-phase AC at 600VAC or 690VAC within 0 to 400Hz — not DC circuits
  • Trip class requirement is Class 10A — tripping in 10 seconds or less at 600% overload per IEC 60947-4-1
  • Contactor is one of: LC1D09, LC1D12, LC1D18, LC1D25, LC1D32, or LC1D38 — direct-mount fit is confirmed across this range
  • Phase-loss sensitivity is required — LRD16 detects single-phase loss and phase unbalance as standard
  • Reset mode flexibility is needed — manual and automatic reset are both selectable post-purchase via dial, no tools required

If your motor FLA is below 9A, the LRD07 (6–9A), LRD02 (3.6–5.4A), or LRD01 (2.4–3.6A) is the correct selection. If FLA exceeds 13A, move to the LRD21 (12–18A) or LRD22 (18–25A). Ordering the LRD16 outside its 9–13A window is the most common and most costly mistake buyers make — more on this below.

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What the LRD16 Actually Does in a Motor Control Circuit

The LRD16 is a three-pole bimetallic thermal overload relay. Its job is straightforward and critical: it monitors the current drawn by a three-phase AC motor and trips the motor control circuit when that current exceeds the relay's set threshold for long enough to indicate a genuine overload condition. The trip mechanism is a bimetallic strip that deflects when heated by excess current — a proven thermal sensing approach that requires no external power supply, no electronics, and no configuration software.

What sets the LRD16 apart from simpler overload devices is its ambient temperature compensation. The bimetallic design self-adjusts across the full -20 to +60°C operating range without derating, which means the relay maintains consistent trip accuracy whether it is mounted in an air-conditioned control room or a sun-exposed outdoor panel. Phase-loss sensitivity is built in as standard, detecting single-phase loss or phase unbalance conditions that bimetallic-only designs without this feature would miss until the motor windings were already overheating.

The relay connects directly to the face of any TeSys D contactor from LC1D09 through LC1D38, creating a compact integrated motor starter assembly. Alternatively it can be wired standalone, making it a flexible retrofit option for panels where the contactor is already installed. The 1NO plus 1NC auxiliary contact configuration allows the relay's trip signal to feed a PLC input, an indicator lamp, or a remote alarm circuit up to 240VAC at 1.5A on the signalling circuit.

Where the LRD16 Sits in a Typical Motor Starter System

The LRD16 occupies the protection layer immediately between the contactor and the motor terminals. Understanding this position helps both specification engineers and installation technicians visualize the complete assembly before ordering components.

  • Upstream supply — three-phase AC power at 600VAC or 690VAC feeds the motor starter enclosure through a disconnect or circuit breaker
  • Contactor — an LC1D09 through LC1D38 TeSys D contactor switches power to the motor; the LRD16 mounts directly to the top of this contactor
  • LRD16 relay — monitors current on all three phases simultaneously; trips and opens the control circuit if overload or phase loss is detected
  • Auxiliary contact output — the LRD16's 1NO / 1NC contacts wire into the control circuit to drop out the contactor coil or signal a PLC or HMI on fault
  • Downstream motor — three-phase AC motor with nameplate FLA between 9 and 13A; typical application is a 5.5kW motor at 400V per manufacturer documentation

Which Motors and Industries the LRD16 Protects

The LRD16 is sized for the motor class that appears most frequently in commercial and light industrial installations — the 5.5kW to 7.5kW three-phase motor range at 400V, as confirmed by manufacturer documentation. Pumping stations and water treatment facilities are among the most common deployments, where submersible or centrifugal pump motors run continuously and phase-loss events from utility supply issues represent a real and recurring damage risk.

HVAC systems rely on the LRD16 for fan motor and compressor protection, particularly in rooftop units and air handling equipment where variable ambient temperatures make the relay's built-in thermal compensation a practical advantage over non-compensated alternatives. Conveyor lines and material handling systems use the LRD16 where motors drive belt drives or chain drives at consistent loads within the 9–13A window.

Manufacturing floor motor circuits — including those driving small mixers, augers, pumps, and blowers in food processing, chemical handling, and packaging lines — also fall within the LRD16's application envelope. The relay's CSA C22.2 No. 14 and UL 508 certifications satisfy North American code requirements for industrial control equipment, while ATEX 94/9/EC compliance opens its use in designated hazardous area applications where ignition risk must be controlled.

Application Typical Deployment
Pumping stations Direct-mount to LC1D18 or LC1D25 contactor driving centrifugal pump motor, continuous duty, phase-loss detection active
HVAC fan and compressor control Integrated motor starter in rooftop AHU panel, ambient compensation required for outdoor temperature range
Conveyor and material handling Motor starter assembly with LC1D12 or LC1D18, manual reset selected for attended maintenance areas
Wastewater treatment Standalone wiring in existing panel, automatic reset for unattended remote pump stations
Manufacturing floor motor circuits Retrofit replacement of aged overload relay in existing TeSys D starter, matching motor FLA 9–13A confirmed before ordering
Compressor protection Direct-mount on LC1D25 or LC1D32 contactor, Class 10A trip to protect compressor windings from sustained overload

LRD16 Specifications That Drive the Purchase Decision

Parameter Value Notes
Current adjustment range 9–13A Continuously adjustable within range; must match motor FLA
Trip class Class 10A Trips in 10 seconds or less at 600% overload per IEC 60947-4-1
AC power circuit voltage 600V / 690V CSA certified at 600V; IEC rated at 690V; not for DC circuits
Frequency range 0–400Hz Bimetallic design compensated across full range
Number of poles 3 Three-phase motor protection only
Auxiliary contact 1NO + 1NC Signalling circuit rated 240VAC / 1.5A; 5A at 240VAC on auxiliary contact
Operating temperature -20 to +60°C No derating required; ambient compensation built in
Enclosure protection IP20 Conforming to IEC 60529
Dimensions (L x W x H) 70 x 45 x 66mm Direct-mount or standalone installation
Reset mode Manual or automatic Field-selectable via dial post-purchase, no tools required

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

LRD16 vs LRD21, LRD07 and the Rest of the TeSys D Family

The LRD product family covers a continuous current range from 2.4A at the low end to 25A at the top of the bimetallic range, with solid-state alternatives available for 90–150A applications. Every model shares the same direct-mount interface with TeSys D contactors and the same manual/automatic reset selectability. Current range is the only axis that matters when choosing between them.

Model Current Range Compatible Contactors Best Application When to Avoid
LRD01 2.4–3.6A LC1D09, LC1D12 Very small motors under 1.5kW Motor FLA above 3.6A
LRD02 3.6–5.4A LC1D09, LC1D12, LC1D18 Small motors under 2kW Motor FLA above 5.4A
LRD07 6–9A LC1D18, LC1D25 Motors in the 6–9A FLA range Motor FLA above 9A or below 6A
LRD16 9–13A LC1D09–LC1D38 Motors 5.5–7.5kW at 400V Any motor FLA outside 9–13A
LRD21 12–18A LC1D18, LC1D25, LC1D32, LC1D38 Motors 7.5–11kW Motor FLA below 12A
LRD22 18–25A LC1D32, LC1D38 Larger industrial motors Motor FLA below 18A
Solid-state (90–150A) 90–150A Separate control Very large motors requiring electronic precision Standard industrial motor sizes; higher cost

Notice the overlap between LRD16 (9–13A) and LRD21 (12–18A) in the 12–13A band. If your motor FLA lands at 12A or 13A, either relay is technically within range — choose LRD16 if you want the tighter, more sensitive setting for a motor that genuinely runs at that current; choose LRD21 if the motor has high starting current transients that benefit from slightly more headroom. When motor FLA exceeds 13A, the LRD21 is the correct and only appropriate choice — verify current availability for the full LRD range at LeadTime.ca.

Expert Verdict: Who Should Order the LRD16 and When to Choose Something Else

The LRD16 is the workhorse selection for engineers and maintenance teams protecting three-phase motors in the 5.5kW to 7.5kW class. Its bimetallic ambient-compensated design eliminates the complexity and cost of solid-state electronics while delivering proven thermal protection across industrial temperature ranges from -20 to +60°C. The direct-mount interface with TeSys D contactors from LC1D09 through LC1D38 — covering the full commercial TeSys D family — means this relay fits an exceptionally wide range of existing installations and new designs without adapter hardware. For plant maintenance teams replacing aged relays in existing TeSys D starters, OEM engineers building compact motor starter assemblies, or electrical contractors specifying pumping, HVAC, and conveyor motor circuits where FLA is confirmed in the 9–13A range, the LRD16 delivers reliability at a predictable cost point with no surprises.

Where the LRD16 falls short is equally clear. It is a three-pole, three-phase-only device — single-phase motor applications require a different product entirely. It has no electronic diagnostics, no remote monitoring capability, and no programmable trip curve — if your application mandates IoT connectivity, real-time data logging, or adjustable characteristic curves, a solid-state or microprocessor-based relay is the correct specification. Applications requiring sub-second trip response should evaluate Class 20 or solid-state alternatives. And if phase-loss sensitivity creates a constraint rather than a benefit in your process — some continuous-process facilities prefer to continue single-phase operation rather than shut down — you need to evaluate whether the LRD16's built-in phase unbalance detection aligns with your operational policy. For motors outside the 9–13A window, the answer is simply a different LRD model: LRD07, LRD21, or LRD22 depending on your FLA.

From a procurement standpoint, the LRD16 is normally stocked in distribution, which means lead time is typically short for standard orders — though stock levels should always be confirmed before committing to a project schedule, particularly for critical motor protection applications where a delayed relay holds up an entire motor starter assembly. The four certifications this relay carries — ATEX 94/9/EC, CSA C22.2 No. 14, UL 508, and IEC 60947-4-1 — cover Canadian, U.S., European, and hazardous-area installations without additional approval steps. Ordering through a specialist industrial automation distributor rather than a generalist electrical supply channel pays dividends specifically for this product: contactor compatibility verification, amperage confirmation against your motor FLA, and same-business-day order processing reduce the risk of a wrong-part shipment that adds days or weeks to a project. Check current LRD16 pricing and availability at LeadTime.ca — the team can confirm compatibility before your order is placed.

For volume pricing or to confirm lead time before committing to a build, contact the LeadTime.ca team directly — we ship worldwide.

What Engineers Need to Know Before Ordering the LRD16

Because community discussion specific to the LRD16 is sparse in public automation forums, the most useful guidance available comes from the pattern of ordering errors and field installation mistakes that specialist distributors and application engineers encounter repeatedly. The LRD16 is a well-understood, mature product — its specifications are stable and its application envelope is tightly defined — which means the risk is almost never in the product itself. The risk is in the selection and verification steps taken before the order is placed.

The single most documented source of problems with thermal overload relay orders across the TeSys D family is amperage mismatch. Engineers or technicians who are replacing an existing relay sometimes reference the panel schedule or the contactor label rather than the motor nameplate, and end up ordering a relay sized for the contactor rather than the motor. The LRD16's 9–13A range is fixed — there is no adjustment range that compensates for a motor running at 7A or 16A. An undersized relay nuisance-trips during normal operation; an oversized relay never trips when it should, leaving the motor exposed to overload damage. Both failure modes are expensive and both are entirely preventable by reading the motor nameplate FLA before picking up the phone or clicking the order button.

Contactor compatibility is the second area where pre-order verification pays off. The LRD16 directly mounts to LC1D09 through LC1D38 — six contactor models covering the full commercial TeSys D range. If the contactor in the panel is outside that family, the direct-mount approach does not apply and standalone wiring with appropriate accessories is required. Taking a photo of the existing contactor nameplate and sharing it with the distributor before ordering takes thirty seconds and eliminates any ambiguity. LeadTime.ca maintains current compatibility references and can confirm fit before the order is entered, which is exactly the type of pre-sale technical check that prevents re-stocking fees and project delays. When in doubt about any of the selection criteria below, reaching out before ordering is the lower-risk path.

Wiring and Installation Overview

  • De-energize and lock out the circuit before handling the relay — confirm no voltage on incoming power lines and control circuit before any wiring work begins
  • For direct-mount installation, align the LRD16's rear mounting pins with the slot on the TeSys D contactor and apply firm downward pressure until fully seated before connecting any wiring
  • Main power circuit terminals use screw clamp connections — insert wire ends fully and tighten until snug without over-torqueing; verify by gently tugging each conductor after tightening
  • Auxiliary signalling circuit wires connect to the 1NO and 1NC terminals — confirm polarity against your electrical schematic if these contacts feed a PLC input or control relay
  • After installation, set the current adjustment knob within the 9–13A range to match motor nameplate FLA — do not force the knob beyond its mechanical stops — and document the final knob position for maintenance records

Full installation and commissioning procedures are available in the Schneider Electric TeSys D installation documentation. Engineers requiring terminal torque values, specific wire gauge guidance, or trip test procedures should refer to the manufacturer's official installation manual.

Compatible TeSys D Contactors and System Expansion

The LRD16 is verified for direct-mount installation on the following TeSys D contactor models. All accept the relay without adapter hardware or tools.

  • LC1D09 — smallest TeSys D contactor; typical motor applications up to 4kW
  • LC1D12 — common for small motors in the 4–5.5kW range
  • LC1D18 — mid-range standard; available in 24V, 110V, and 230V coil variants; typical 5.5–7.5kW applications
  • LC1D25 — popular industrial size; 24V, 110V, and 230V coil options; typical 7.5–11kW range
  • LC1D32 — larger motor applications; typical 11–15kW range
  • LC1D38 — upper range of the TeSys D family; typical 15–22kW range

Terminal variants for the LRD16 include the standard screw clamp configuration as well as spring terminal and ring terminal options and the EverLink connection system — verify which terminal type is required for your panel before ordering if the application requires a specific connection method.

Wrong-Part Prevention Checklist

Before submitting your order for the LRD16, work through every item on this checklist. These are the exact verification points that prevent wrong-part shipments and installation failures.

  1. Confirm motor nameplate FLA falls between 9–13A; do not use LRD16 for motors outside this range
  2. Verify power supply voltage: 600VAC or 690VAC, 0–400Hz (not for DC circuits)
  3. Confirm contactor model number: LRD16 directly mounts to LC1D09, LC1D12, LC1D18, LC1D25, LC1D32, LC1D38 TeSys D contactors
  4. Check application: if higher current capacity needed, order appropriate higher-amperage model (LRD21, LRD22, or LRD32)
  5. Confirm reset type required: manual or automatic (selectable post-purchase, but verify customer policy)
  6. Verify phase loss detection is required in application (LRD16 has phase unbalance/phase loss sensitivity included)
  7. Check mounting method: direct-mount to contactor vs. standalone installation affects accessory requirements
  8. Confirm lead time acceptability for critical applications (normally stocked distribution, but verify with distributor)

If any item on this checklist raises a question before you order, contact the LeadTime.ca team — confirming compatibility before purchase is faster and less expensive than a return and re-order.

Frequently Asked Questions

Can I use the LRD16 on a motor with a nameplate FLA of 8A or 14A?

No. The LRD16's adjustment range is fixed at 9–13A. A motor running at 8A FLA requires the LRD07 (6–9A range), and a motor at 14A FLA requires the LRD21 (12–18A range). Using the LRD16 outside its rated range either causes nuisance trips during normal operation or, worse, provides no protection when the motor actually overloads.

Does the LRD16 work with TeSys contactors outside the LC1D09–LC1D38 range?

The verified direct-mount compatibility covers LC1D09 through LC1D38 only. For contactors outside this range or from other product families, standalone wiring with appropriate accessories may be possible but must be confirmed against the contactor's installation documentation. When retrofitting into an unfamiliar panel, photograph the contactor nameplate and verify compatibility with your distributor before ordering.

What is the difference between Class 10A and Class 20 trip behavior for motor protection?

The LRD16 is a Class 10A relay, meaning it trips in 10 seconds or less at 600% overload current per IEC 60947-4-1. Class 20 relays allow up to 20 seconds before tripping at the same overload level, providing more tolerance for high-inertia loads with long acceleration times such as large fans or centrifuges. For most standard industrial motor applications — pumps, conveyors, compressors — Class 10A is the correct and more protective choice.

If I need to switch between manual and automatic reset, do I have to replace the relay?

No. Manual and automatic reset modes are both selectable via the adjustment dial on the face of the LRD16 after installation, with no tools required. This means the reset mode can be changed in the field to match operational requirements without ordering a different relay variant.

Is the LRD16 suitable for single-phase motors?

No. The LRD16 is a three-pole relay designed exclusively for three-phase AC motor protection. Single-phase motor applications require a different type of overload protection device. Attempting to use a three-pole relay on a single-phase circuit will not provide correct protection and may result in incorrect trip behavior.

What certifications does the LRD16 carry for Canadian and North American installations?

The LRD16 carries CSA C22.2 No. 14 certification for Canadian electrical installations and UL 508 certification for U.S. industrial control equipment. It is also CE marked, ATEX 94/9/EC compliant for hazardous area applications, and certified to IEC 60947-4-1 and IEC 60947-5-1 international standards. These certifications cover the full range of North American and international industrial installation requirements without additional approvals.

Why Order the LRD16 From LeadTime.ca

  • Global shipping — LeadTime.ca fulfills orders worldwide, not limited to any single region or market
  • Pre-order compatibility verification — the team can confirm contactor fit and amperage match against your motor specifications before the order is placed
  • Access to the full LRD product family — if LRD16 stock is delayed or your FLA requires a different variant, alternatives are sourced immediately from the same specialist channel
  • Volume pricing available — contact for current pricing on project quantities or blanket orders for facilities with multiple motor starter assemblies
  • Pricing is available directly on the product page — Shopify displays live pricing automatically, or contact for a formal quote

At-a-Glance Summary

  • Current adjustment range: 9–13A — fixed; must match motor nameplate FLA exactly
  • Trip class: Class 10A — trips in 10 seconds or less at 600% overload per IEC 60947-4-1
  • Voltage rating: 600VAC (CSA/UL) and 690VAC (IEC) — three-phase AC only, 0–400Hz
  • Typical application: 5.5kW motor at 400V — confirmed in manufacturer documentation
  • Direct-mount compatibility: LC1D09, LC1D12, LC1D18, LC1D25, LC1D32, LC1D38 — full commercial TeSys D range
  • Operating temperature: -20 to +60°C with no derating — bimetallic ambient compensation built in
  • Enclosure: IP20 per IEC 60529
  • Auxiliary contact: 1NO + 1NC — signalling circuit rated 240VAC / 1.5A
  • Reset mode: manual or automatic — field-selectable via dial, no tools required
  • Phase-loss sensitivity: included as standard — detects single-phase loss and phase unbalance
  • Dimensions: 70 x 45 x 66mm
  • Certifications: ATEX 94/9/EC, CE, CSA C22.2 No. 14, UL 508, IEC 60947-4-1, IEC 60947-5-1, RoHS
  • Flammability: UL94 V-1 rated
  • If FLA is outside 9–13A: order LRD01, LRD02, LRD07, LRD21, or LRD22 as appropriate

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