--- title: "MPCB vs Thermal Relay + Contactor: Which Is Better?" date: 2025-07-08T08:32:58Z modified: 2025-07-17T02:33:25Z permalink: "https://www.simplybuyglobal.com/blog/circuit-breaker/mpcb-vs-mccb-motor-protection/" type: post status: publish excerpt: "" wpid: 1750 categories: - circuit breaker featured_image: "https://www.simplybuyglobal.com/wp-content/uploads/2025/07/6ff23dcf-2b25-4277-9c40-6605d35522dc.webp" featured_image_alt: "MPCB vs Thermal Relay + Contactor: Which Is Better?" timestamp: 2025-07-17T02:33:25Z tags: - circuit breaker --- When it comes to the difference between MPCB and overload relay, the former, which stands for motor protection circuit breaker, combines the capabilities for overload, short-circuit, and phase failures in just one device. Meanwhile, the latter is only capable of protecting against overload, so they require a separate contactor for switching and a circuit breaker for protecting against short circuits. It is important to know their differences to ensure the right motor protection, safety, cost-effectiveness, and compliance with the electrical standards and requirements of the industry. This comparative guide by [SIMPLYBUY](https://www.simplybuyglobal.com/) will tackle the following: [![about Simply Buy motor controls, VFDs, and breakers—original, in-stock, and fast shipping.](https://www.simplybuyglobal.com/wp-content/uploads/2025/07/1752296239248-1200x596.webp) ](https://www.simplybuyglobal.com/) – The MPCB motor protection circuit breaker – How a thermal overload relay and contactor work together – The head-to-head comparison – When is an MPCB the winner? – Are there still cases for using a separate overload relay? [Get Free Quote](https://www.simplybuyglobal.com/contact/) ## **What Is a Motor Protection Circuit Breaker (MPCB)?** Prior to learning stuff on MPCB vs. MCCB, it is crucial to first know what MPCBs are. Well, these [circuit breakers](https://www.simplybuyglobal.com/wp-content/uploads/wp-mfa-exports/taxonomy/product_cat/circuit-breaker.md) are more for motor protection rather than control. This technology is built to protect your electric motors from faulty issues, from short-circuiting to unstable voltage levels. Note, though, that MPCBs are totally distinct from standard circuit breakers in such a way they do not isolate motors from their power supplies during the encounter of the issues, but also guarantee that the motor is in the right load. In the world of electrical engineering, it is your all-in-one apparatus used in motor control circuits that play critical roles, such as: - Short circuit protection - Phase failure protection - Restart lockout, and more Hero Product Highlight [ ![Schneider Electric PowerPacT H-Frame HDA36100](https://www.simplybuyglobal.com/wp-content/uploads/2025/04/HDA36100.webp) Schneider Electric PowerPacT H-Frame HDA36100 **Rated Current**: 100 A (thermal-magnetic, 80% continuous rating) **Poles**: 3P (ABC phase connection) **Rated Voltage**: 600 V AC / 250 V DC **Breaking Capacity (IEC 60947-2)**: • 25 kA @ 240 V AC • 18 kA @ 480 V AC • 14 kA @ 600 V AC • 20 kA @ 250/500 V DC View Product ](https://www.simplybuyglobal.com/product/schneider-electric-powerpact-h-frame-hda36100/)## **The Classic Combo: How a Thermal Overload Relay and Contactor Work Together** Thermal overload relays are safety devices used in manual control circuits. They use an electric motor to control the overheat or short-circuiting through switching off the heating circuit once the temperature increases and reaches above the set value. Is there a short circuit? This relay will determine. These relays feature two contacts, one that’s normally open and the other that’s usually closed. They form a simple electrical circuit when the two contacts meet together. To utilize a relay, you should first know the type of circuit you wish to protect, such as an appliance or an electrical outlet with several circuits going through it. These devices are used with overcurrent protection devices, such as overnight fuses and shatters, for better protection, as the circuits come into contact with them simultaneously. Hero Product Highlight [ ![TeSys LRD Thermal relays](https://www.simplybuyglobal.com/wp-content/uploads/2025/05/TeSys-LRD-1.jpg) TeSys LRD Thermal relays **Manufacturer**: Schneider Electric **Model**: TeSys LRD **Type**: Thermal relays **Relay application**: 0.06 kW to 75 kW Motor protection **Product compatibility**: LC1D View Product ](https://www.simplybuyglobal.com/product/tesys-lrd-thermal-relays/)## **Head-to-Head Comparison** | **Points of Comparison** | **MPCBs** | **Thermal overload relay + contactor** | | --- | --- | --- | | Space | Compact, integrated design, capable of saving panel space | More space needed due to separate components | | Wiring time | Speedier, fewer connections needed | Needed to be even slower, and multiple wiring connections required | | Cost | MPBCs are more experienced | If you’re on budget, consider this exercise | | Protection levels | Since you invested in MCPBs, know that there’s one more feature that’s incredibly vital: their protection levels. | The latter poor when it comes to his category. | Here, you are not just comparing oranges to oranges, but two distinct equipment. This is your closer look at their comparison: - **Space**: MPCBs are known for offering a compact and one-stop solution that’s a space saver, compared with thermal overload relays and contactor whose setup requires more room. - **Wiring time**: This wiring time is reduced with the use of MPCBs, especially with their integrated design. Whereas, the traditional combination of a contactor with thermal overload relays demands several connections, increasing the time needed to install. - **Cost**: Though MPCBs are more expensive, the overall and long-term expenses are lesser, since too many components and labor are not required. - **Protection levels**: Meanwhile, MPCBs are stronger when it comes to protecting your electrical systems, covering short-circuiting, phase loss protection, and so much more. The reason why the other is expensive is because of the need for additional devices. [![contact Simply Buy motor controls, VFDs, and breakers—original, in-stock, and fast shipping.](https://www.simplybuyglobal.com/wp-content/uploads/2025/07/1752296109845.webp) ](https://www.simplybuyglobal.com/contact/) **When Is an MPCB the Clear Winner?** Now that you’ve learned the difference between MPCB and overload relay with contactor, it is time that we hear the verdict. As you could see from the above discussion, its clear winner is sill the thermal overload relay. They are very useful for [compact control panels](https://www.simplybuyglobal.com/wp-content/uploads/wp-mfa-exports/taxonomy/product_cat/mpcb.md), quick project turnarounds, and applications against the most common electrical wiring issues. They also enhance homes with efficiency, safety, and ease of maintenance. Hero Product Highlight [ ![SIRIUS 3RV6/3RV5](https://www.simplybuyglobal.com/wp-content/uploads/2025/05/SIRIUS-3RV6-5-1.jpg) SIRIUS 3RV6/3RV5 **Manufacturer**: Siemens **Model**: SIRIUS 3RV6/3RV5 **Type**: Motor Protection Circuit Breakers **Relay application**: Power up to 45 kW at 400V AC or Rated current up to 100A Switching and protection View Product ](https://www.simplybuyglobal.com/product/sirius-3rv6-3rv5/)[![Simply Buy OEM & ODM Solutions ](https://www.simplybuyglobal.com/wp-content/uploads/2025/07/1752297069487-1200x490.webp)](https://www.simplybuyglobal.com/oem-odm/) ## **Are There Still Cases for Using a Separate Overload Relay?** Apart from knowing the difference between MPCB and overload relay, as well as why the former is the better option, it is also important that you see some use cases for your separate overload relay to give you a better picture: - Higher-power and larger motors that require custom coordination with contactors – for more flexibility in handling high current ratings. - Cost-sensitive projects that require high costs, but with simple protection needs that won’t go overboard. - Custom control schemes: Highly flexible, separate components that champion flexibility and easier troubleshooting when advanced control logic or sequencing should be present, but they are not. While both MPCBs and thermal overload relays + contactors could help you reach the goals of your operations, but it is the MPCB equipment trumping against its two facets itself: MCPB and the overload relay. Our company has [motor protection circuits](https://www.simplybuyglobal.com/product/sirius-3rv6-3rv5/) that have all the features you need for: short-circuiting, phase loss, locked rotor protection, tripping adjustment, and so much more. [Coordinate with them today](https://www.simplybuyglobal.com/contact/) to find out more. [![Simply Buy motor controls, VFDs, and breakers—original, in-stock, and fast shipping. global emperor](https://www.simplybuyglobal.com/wp-content/uploads/2025/07/1752295816389-1200x615.webp) ](https://www.simplybuyglobal.com/about-us/)