Square D TeSys K Differential ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$109.70
Square D TeSys K Differential Thermal Overload Relay, 3.7-5.5 A, Class 10A

Square D TeSys K Differential Thermal Overload Relay, 3.7-5.5 A, Class 10A

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Model: LR2K0312

In Stock (leaves warehouse same day if ordered before 3pm ET)

$109.70
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Square D TeSys K Differential Thermal Overload Relay, 3.7-5.5 A, Class 10A

The Square D TeSys K differential thermal overload relay is designed to pair with TeSys K contactors to form a complete motor starter. It monitors line currents to the motor and trips on overcurrent conditions, with a thermal protection adjustment range of 3.7-5.5 A and a Class 10A thermal overload class conforming to IEC 60947-4-1. Rated for a 690V (Ui) insulation voltage on the power circuit and an IP2X degree of protection, this relay is built for industrial and commercial motor control applications.

Key Features

  • Thermal Overload Class: Class 10A conforming to IEC 60947-4-1 for standard motor starting duty.
  • Adjustment Range: 3.7-5.5 A thermal protection adjustment range for precise overcurrent detection.
  • Rated Insulation Voltage: 690V (Ui) power circuit conforming to IEC 60947.
  • Degree of Protection: IP2X conforming to IEC 60529 for touch-safe terminal protection.
  • Control Type: Red push-button trip test function, Blue push-button stop and manual reset, and a selector switch for manual or automatic reset.
  • Local Signalling: Yellow trip indicator for at-a-glance fault status.
  • Contactor Compatibility: Designed for use with LC1K, LC7K, LP1K, and LP4K TeSys K contactors.
  • Mounting Support: Mounts under the contactor, or on a plate or DIN rail with specific accessories.

Certifications & Compliance

  • UL Listed
  • CSA Certified
  • UKCA Marked
  • Conforms to IEC 60947
  • Conforms to VDE 0660
  • Conforms to NF C 63-650
  • Conforms to BS 4941
  • ROHS EUR Compliant

Technical Specifications

  • Toxic Heavy Metal Free: Yes
  • Warranty: 18 months
  • Power Dissipation Per Pole: 2 W
  • Mercury Free: Yes
  • Packaging Without Single Use Plastic: Yes
  • Sustainable Packaging: Yes
  • ROHS Eur In Scope: Yes
  • Recycled Metal Content At Cr Level: 0 %
  • Serviceability: No
  • With Recycled Cardboard: Yes
  • WEEE Product Category: 5
  • Network Frequency: <= 400 Hz
  • Compatibility Code: LR2K
  • Reach Free Shvc: Yes
  • Ambient Air Temperature For Storage: -40-70 °C
  • China ROHS In Scope: No
  • Weee Label: The product must be disposed on European Union markets following specific waste collection and never end up in rubbish bins.

Typical Applications

  • Motor Starter Combinations with TeSys K Contactors
  • Industrial Motor Control Panels
  • Commercial and Industrial Electrical Installations
  • OEM and Control Panel Building
  • AC/DC Motor Circuit Overload Protection

Why Square D?

Square D TeSys K overload relays deliver dependable, code-compliant motor protection backed by UL, CSA, and UKCA certification and compliance with IEC 60947, VDE 0660, NF C 63-650, and BS 4941 standards. With a rugged IP2X-rated design, precise 3.7-5.5 A adjustment range, and Class 10A thermal response, this relay gives electricians, panel builders, and OEMs a reliable component for professional motor starter assemblies.

Manufacturer Resources

Product Specs

Product Type:
Thermal Overload Relay
Series:
TeSys K
Amperage Rating:
3.7-5.5 A
Voltage Rating:
690V
Listing:
UL
Standards:
IEC 60947
Department:
Electrical
Product Group:
Wiring Devices
Product Subgroup:
Motor Starters & Contactors

Square D LR2K0312 – Frequently Asked Questions

1) What motor full load current does the 3.7-5.5 A TeSys K overload relay cover?
Set point adjusts anywhere from 3.7 to 5.5 amps, so it protects motors whose nameplate full load current falls inside that band. You dial the relay to the motor's actual FLA, not to the top of the range. If your motor draws below 3.7 A or above 5.5 A, this is the wrong unit in the family and you need the adjacent LR2K rating.
2) Is this Square D overload relay UL listed for use in a North American control panel?
Yes, the TeSys K thermal overload relay is UL Listed and CSA Certified, and also carries UKCA marking with conformity to IEC 60947, VDE 0660, NF C 63-650 and BS 4941. That combination is what panel builders shipping into both North American and European markets normally need on the same bill of material.
3) Does this relay reset automatically after a trip, or does someone have to go to the panel?
Both, your choice. A selector switch on the relay sets manual or automatic reset. On the front there is a blue push-button for stop and manual reset, a red push-button that tests the trip function, and a yellow indicator that shows a trip has occurred. For unattended equipment auto reset saves a truck roll; for anything with a safety implication, keep it on manual.
4) What is the closest alternative to the Square D LR2K0312 overload relay if I am not building on TeSys K contactors?
The Square D LR2K0312 is a differential thermal overload relay with a 3.7-5.5 A adjustment range, Class 10A per IEC 60947-4-1, and it is built to mount under LC1K, LC7K, LP1K and LP4K TeSys K contactors. If your starter is not TeSys K, the ABB TF42-16 thermal overload relay is also a Class 10 thermal overload device and belongs to ABB's TF42-16 series, which pairs with ABB's own contactor line rather than TeSys K. Overload relays are not universally cross-mountable between manufacturers, so match the relay to the contactor family already in the panel.
5) Do I need a Class 20 overload relay instead of the Square D LR2K0312 for a high-inertia motor load?
The Square D LR2K0312 is a Class 10A relay conforming to IEC 60947-4-1, which is standard motor starting duty and trips relatively quickly on a sustained overcurrent. Loads with long acceleration times, such as high-inertia fans or centrifuges, are often specified with a Class 20 relay instead so the motor can come up to speed without nuisance tripping. The Eaton three-pole thermal overload relay in the A200 series is a Class 20 device and is NEMA starter-mounted, so it suits a NEMA starter rather than an IEC TeSys K assembly.
6) My panel drawing calls for a NEMA starter overload. Will the Square D LR2K0312 work?
The LR2K0312 is an IEC-style differential thermal overload relay that mounts under a TeSys K contactor or, with specific accessories, on a plate or DIN rail. It is not a NEMA starter-mounted heater-style overload. For a NEMA starter the Eaton three-pole thermal overload relay in the A200 series is the NEMA starter-mounted type and is rated Class 20. Confirm which starter standard the drawing specifies before ordering, since the mounting interfaces are not interchangeable.
7) Can I use the TeSys K LR2K0312 relay on a 600V motor circuit?
Rated insulation voltage on the power circuit is 690V (Ui) to IEC 60947, so a 600V circuit is inside the insulation rating. Note that Ui is an insulation figure, not the operating voltage of a motor starter on its own; the actual starter rating comes from the TeSys K contactor you pair it with.
8) What is a differential thermal overload relay and why does it matter for three-phase motors?
Differential means the relay reacts to unbalance between the three line currents as well as to straight overcurrent. Lose a phase and a plain thermal relay may sit there while the motor cooks on the two remaining legs; a differential unit like the LR2K0312 trips faster on that condition. It is the reason this style is specified on three-phase motor starters rather than a basic bimetal block.
9) Are the terminals on this overload relay finger-safe?
Degree of protection is IP2X to IEC 60529, which is the finger-safe level, so the terminals are guarded against contact by a finger during work in a live panel. Power dissipation is 2 W per pole, which is what you use for panel heat load calculations.
10) What are the alternatives if I am not building on a TeSys K contactor?
The LR2K relay only fits the TeSys K family, so on a different platform you match the relay to that manufacturer's starter. ABB's TF42-16 is a Class 10 thermal overload relay for ABB contactors, and Eaton's A200 series three-pole relay is a Class 20 unit that mounts on NEMA starters. Pick by the contactor already in the panel, not by the amp range alone.
11) What is the difference between the Square D LR2K0312 and the ABB TF42-16 overload relay?
Both are thermal overload relays for motor branch protection and both are Class 10 devices. The Square D LR2K0312 is a differential thermal relay with a 3.7-5.5 A adjustment range, 690V rated insulation voltage on the power circuit, IP2X protection, a red trip-test push-button, a blue stop and manual reset button, a manual/auto reset selector and a yellow trip indicator, and it mounts to TeSys K contactors. The ABB TF42-16 is ABB's TF42-16 series Class 10 relay and is sized and mounted to ABB's contactor range. The practical deciding factor is which contactor family the starter is built on.
12) If I need a wider current setting than 3.7-5.5 A, what should I look at?
The Square D LR2K0312 is set for a 3.7-5.5 A thermal protection adjustment range, which suits small motors drawing full-load current inside that band. For larger motor full-load currents, the ABB TF42-16 thermal overload relay covers ABB's TF42-16 frame, which is the larger-frame Class 10 relay in that family. Size any overload relay so the motor nameplate full-load amps fall within the relay's adjustment band, and keep the relay in the same family as the contactor it mounts to.
13) Does the UL listing on the Square D LR2K0312 carry over if I substitute another brand's relay?
The Square D LR2K0312 is UL Listed and CSA Certified, UKCA marked, and conforms to IEC 60947, VDE 0660, NF C 63-650 and BS 4941. Certification belongs to the specific device, so substituting a different relay means verifying that part's own listings against the job specification. The ABB TF42-16 and the Eaton A200 series three-pole relay are each Class 10 and Class 20 devices respectively, and each carries its own agency approvals that must be checked against what the panel submittal requires.
14) Will this Square D relay work on a variable frequency or high frequency supply?
Network frequency is rated at less than or equal to 400 Hz, so it covers 50 and 60 Hz mains plus higher frequency supplies up to 400 Hz. Storage ambient is -40 to 70 degrees C, which matters if stock sits in an unconditioned warehouse or the panel ships overseas before commissioning.
15) Is the LR2K0312 a repairable part or a replace-on-failure item?
Replace on failure. Serviceability is listed as no, so a tripped-and-damaged relay comes out and a new one goes in rather than being rebuilt. It is also mercury free, free of toxic heavy metals, RoHS EUR compliant and shipped in recycled cardboard without single use plastic, which is what sustainability-minded distributors and public sector buyers usually have to document.
How fast can I get the Square D LR2K0312 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Square D LR2K0312 come with a warranty?
Absolutely. The Square D LR2K0312 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Square D LR2K0312?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
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