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Brand: Schneider Electric
Schneider Electric LRD3355 Thermal Overload Relay 30-40 A for
Description
LRD3355 bimetal overload relay for LC1D80 and LC1D95
The LRD3355 is a Schneider Electric product listed in the datasheet as: TeSys Deca, thermal overload relay, 30 to 40 A, class 10A, for LC1D80 and LC1D95. The LRD3355 is a differential thermal overload relay from the TeSys Deca LRD series. It protects a motor drawing 30 to 40 A and attaches under the LC1D80 or LC1D95 contactor. Seven Star LLC supplies the LRD3355 in Oman and the GCC as an independent supplier based in Muscat.
Reading the reference: LRD marks the thermal relay series, and 3355 identifies the 30 to 40 A band for the larger LC1D frames (title: 30 to 40 A, class 10A, for LC1D80). The datasheet states the contactors it fits.
Technical specifications of the LRD3355
| Parameter | Specification |
|---|---|
| Manufacturer / part number | Schneider Electric / LRD3355 |
| Description | TeSys Deca, thermal overload relay, 30 to 40 A, class 10A, for LC1D80 and LC1D95 |
| Range | TeSys |
| Product name | TeSys LRD; TeSys Deca |
| Product or Component Type | Differential thermal overload relay |
| Device short name | LRD |
| Relay application | Motor protection |
| Product Compatibility | LC1D80; LC1D95 |
| Network type | DC; AC |
| Thermal overload class | Class 10A IEC 60947-4-1 |
| Thermal protection adjustment | 30 to 40 A |
| [Ui] rated insulation voltage | Power circuit 1000 V IEC 60947-4-1; Power circuit 600 V CSA; Power circuit 600 V UL |
| Network Frequency | 0 to 400 Hz |
| Mounting support | Plate, with specific accessories; Rail, with specific accessories; Under contactor |
| Tripping threshold | 1.14 ± 0.06 Ir IEC 60947-4-1 |
| Auxiliary contact composition | 1 NO + 1 NC |
| [Ith] conventional free air thermal | 5 A signalling circuit |
| Permissible current | 0.72 A 500 V AC-15 signalling circuit; 0.06 A 440 V DC-13 signalling circuit |
| [Ue] rated operational voltage | 1000 V AC 0 to 400 Hz power circuit IEC 60947-4-1 |
| Associated fuse rating | 4 A gG for signalling circuit; 4 A BS for signalling circuit |
| [Uimp] rated impulse withstand | 6 kV IEC 60947-1 |
| Phase failure sensitivity | Tripping current 130 % of Ir on two phase, the last one at 0 |
| Control type | Red push-button stop; Blue push-button reset |
| Temperature compensation | -20 to 60 °C |
| Connections – terminals | Power circuit screw clamp terminals 1 4 to 35 mm² flexible without cable end |
| Height | 81 mm |
| Width | 70 mm |
| Depth | 115 mm |
| Net Weight | 0.51 kg |
| Climatic withstand | IACS E10 |
| IP degree of protection | IP20 conforming to IEC 60529 |
| Ambient air temperature (operation or storage, as listed) | -20 to 60 °C without derating IEC 60947-4-1 |
| Flame retardance | V1 conforming to UL 94 |
| Mechanical robustness | Vibrations6 Gn IEC 60068-2-6; Shocks15 Gn for 11 ms IEC 60068-2-7 |
| Dielectric strength | 2.2 kV 50 Hz IEC 60947-1 |
| Standards | EN/IEC 60947-4-1; EN/IEC 60947-5-1; UL 60947-4-1; UL 60947-5-1; CSA C22.2 No 60947-4-1; CSA C22.2 No 60947-5-1; GB/T 14048.4; GB/T 14048.5 |
| Product Certifications | IEC; UL; CSA; CCC; EAC; ATEX INERIS; UKCA |
Trip behaviour and settings
Adjustment range: 30 to 40 A. Overload class: Class 10A IEC 60947-4-1. Tripping threshold: 1.14 ± 0.06 Ir IEC 60947-4-1. Phase-failure behaviour: Tripping current 130 % of Ir on two phase, the last one at 0. Front controls: Red push-button stop; Blue push-button reset. Auxiliary contacts: 1 NO + 1 NC.
A bimetal relay heats a strip with the motor current, and a differential mechanism makes it more sensitive to loss of one phase. Class 10A means it should trip within 10 seconds at six times the setting, which suits normal-start motors. For long starting times the electronic LR9D series with class 20 is the alternative.
Pairing the LRD3355 with contactors and breakers
The relay is made for LC1D80 and LC1D95 contactors, as stated in the compatibility list. A motor of 30 to 40 A at 400 V is about 15 to 22 kW. If the same motor needs reversing, the relay works with the LC2 reversing pair via a mounting plate listed in the datasheet.
For the lower currents, smaller relays in the same series cover the lower bands: for example LRD12 is a 5.5 to 8 A model for small frames.
Selection checklist for the LRD3355
- Motor nameplate current between 30 and 40 A, preferably in the middle of the range.
- Contactor type LC1D80 or LC1D95.
- Class 10A suits the starting time of the load.
- Manual or automatic reset preference.
- Alarm contact wiring: 1 NO plus 1 NC are provided.
- Temperature compensation and the panel ambient.
Setting and maintaining the LRD3355
Mount the relay under the contactor, tighten the power terminals to the datasheet torque and set the dial to the nameplate current. Use the test button to confirm that the trip contact opens, then press reset.
A thermal relay should be tested after any tripping caused by a short-circuit. Replace it if the case shows heat damage; do not adjust its setting above the motor nameplate.
Typical applications of the LRD3355 in Oman and the GCC
In Oman and the GCC it protects medium pump, fan and compressor motors fed from the plant MCC. Hot cabinets reduce the margin of a bimetal relay, so check ambient compensation and keep panel temperature low.
Dimensions, environment and approvals of the LRD3355
For the LRD3355, plan the mounting space from the datasheet: 70 mm (W) x 81 mm (H) x 115 mm (D). The LRD3355 weighs 0.51 kg. Mounting, derating and enclosure choices follow the environmental data below, which should be compared with the actual panel temperature and the dust and humidity of the site in Oman and the GCC.
Ambient temperature limits in the datasheet: -20 to 60 °C without derating IEC 60947-4-1. Ingress protection: IP20 conforming to IEC 60529. Standards listed: EN/IEC 60947-4-1; EN/IEC 60947-5-1; UL 60947-4-1; UL 60947-5-1; CSA C22.2 No 60947-4-1; CSA C22.2 No 60947-5-1; GB/T 14048.4; GB/T 14048.5. Certifications listed for this reference: IEC; UL; CSA; CCC; EAC; ATEX INERIS; UKCA.
Information to send with an RFQ for the LRD3355
- Full reference and quantity required
- Existing equipment, panel or rack it must fit
- Supply voltage, load or signal details of the application
- Required delivery location and timing
- Whether a spare, a replacement or a new installation
Documents and quotation
A datasheet for this product is attached on this page. It lists the electrical, mechanical and environmental data summarised above.
Send us the part number, quantity and application and we will confirm availability and a quotation. Seven Star LLC is an independent supplier in Muscat and does not represent itself as an official channel of the manufacturer.
Datasheets & Documents
- Datasheet Schneider Electric LRD3355 Datasheet Download
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About brand
Schneider Electric is the French group for energy management and industrial automation: low and medium voltage switchgear and circuit breakers, motor control, drives, PLCs, power monitoring, UPS systems and building management. Its history goes back to 1836, when the brothers Adolphe and Eugène Schneider took over the iron and steel works at Le Creusot in Burgundy. Over the 20th century the company left steel and heavy engineering and became an electrical group through acquisitions such as Merlin Gerin, Télémécanique, Square D and Modicon. Its head office is in Rueil-Malmaison near Paris, and its shares are listed on Euronext Paris.
Schneider Electric company profile
| Origins | 1836, Le Creusot, France: Adolphe and Eugène Schneider take over the Le Creusot foundry |
|---|---|
| Headquarters | Rueil-Malmaison (Paris region), France |
| Ownership | Public company listed on Euronext Paris |
| Key acquisitions | Télémécanique (1988), Square D (1991), Merlin Gerin (1992), Modicon (1997), APC (2007), Invensys (2014); majority owner of AVEVA software |
| Brand names still in use | Acti9, ComPacT and MasterPacT breakers, TeSys motor control, Altivar drives, Altistart soft starters, Modicon PLCs, Harmony control components, PowerLogic and Easergy protection and metering, APC UPS, EcoStruxure software platform |
| Product families | Low voltage distribution, medium voltage switchgear and protection relays, motor control and drives, PLCs and HMIs, power meters, UPS and cooling, enclosures, building automation and energy software |
Milestones
- 1836: The Schneider brothers acquire the Le Creusot works; the business grows in steel, locomotives and heavy engineering.
- 1975: First investment in Merlin Gerin, a French maker of electrical distribution equipment.
- 1988–1992: Télémécanique, Square D (USA) and Merlin Gerin join the group, making it an electrical specialist.
- 1997: Modicon, the company behind the first programmable logic controller, joins the group.
- 1999: The group takes the name Schneider Electric.
- 2007 and 2014: APC (UPS and data centre power) and Invensys (process automation) are acquired.
Choosing Schneider Electric breakers and motor control
Circuit breakers are chosen by current and breaking capacity. Acti9 miniature circuit breakers (iC60, C120) protect final circuits up to 125 A. ComPacT NSX molded case breakers cover about 16 to 630 A, and the letter after the frame size sets the breaking capacity: B, F, N, H, S, L from lowest to highest. MasterPacT air circuit breakers are used as main incomers on large switchboards. For motors, a TeSys contactor with an LRD overload relay or a GV2 motor circuit breaker suits direct starting, an Altistart soft starter reduces starting current, and an Altivar drive controls speed. The breaking capacity must always be at least the prospective short-circuit current at the point of installation.
Where Schneider Electric products are used
In Oman and the GCC, Schneider Electric equipment is found in main and sub-main switchboards of commercial and residential buildings, motor control centres in water, oil and gas and industrial plants, substations protected by Sepam and Easergy relays, data centres powered by Galaxy and APC UPS systems, and buildings controlled by EcoStruxure Building Operation.
APC by Schneider Electric: UPS and critical power
Since 2007, APC has been part of Schneider Electric and is now its product brand for uninterruptible power supplies, replacement batteries, battery packs, network management cards and rack power distribution. Our APC catalogue covers Smart-UPS line-interactive and on-line models, Easy UPS On-Line, the modular Symmetra LX, RM and PX ranges, Silcon three-phase systems and their spare part kits, and the RBC cartridges that keep them running. Schneider Electric breakers, drives and PLCs can be quoted together with APC UPS systems in one request.
Schneider Electric products we list
| Family | Examples |
|---|---|
| Circuit breakers | Acti9 iC60N, C120N, NSX100F, NSX250N, NSX630, EasyPact EZC, MasterPacT MTZ1, MasterPacT NW |
| Motor control | TeSys Deca LC1D, TeSys F, LRD overload relay, GV2ME08, Altistart 22, Altistart 480 |
| Drives | Altivar 12, Altivar 320, ATV340, Altivar Process 630, ATV930, Lexium 32 servo |
| PLCs, HMIs and relays | Modicon M221, M241, M580 BMEP582040, Zelio Logic, Magelis HMISTU655 |
| Protection, metering and power | Sepam series 20, Easergy P3U30, MiCOM P139, PM5560, iEM3255, Galaxy VS UPS |
Ordering Schneider Electric products: what we need
Send the commercial reference from the label (for example LC1D18M7 or ATV320U22N4C). For breakers, confirm the rated current, number of poles, breaking capacity and trip unit. For contactors, give the coil voltage. For drives, give the motor power and supply voltage. APC products are listed on their own brand page.
Facts checked against Schneider Electric's published company history, October 2026.
Browse Schneider Electric products by category: Circuit Breaker, Electrical & Power Modules, AC Drives, PLC & I/O Cards, Metering Systems, UPS and Batteries.
FAQ
Questions about the Schneider Electric LRD3355 Thermal Overload Relay
Answers from our engineering team on installation, compatibility and integration.
01What current setting range has the LRD3355?
The datasheet lists 30 to 40 A.
02Which contactors take the LRD3355?
Compatible: LC1D80; LC1D95.
03What class is the LRD3355?
Stated as Class 10A IEC 60947-4-1.
04How does it react to phase loss?
Datasheet: Tripping current 130 % of Ir on two phase, the last one at 0.
05What is its trip threshold?
Listed: 1.14 ± 0.06 Ir IEC 60947-4-1.
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