MP Blog 2017

Understanding the Elements of a Quality Circuit Breaker

kstrangeway@mechprod.com (Karie Strangeway) — Mon, 21 Apr 2025 12:45:00 GMT

Understanding the Elements of a Quality Circuit Breaker

Choosing a circuit breaker might seem simple—especially if cost is your only concern. A quick online search can yield several manufacturers, and with a few positive reviews about timely delivery and functionality, it’s tempting to make a purchase. But is that really enough?

A circuit breaker is a critical safety device, designed to protect people and equipment from overcurrent hazards, while allowing the maximum demand of the protected circuit. When a breaker fails to perform properly, the consequences can be severe—overheating, melted wires, and burned-out motors, to name a few.

When sourcing a circuit breaker, it’s essential to look beyond the price tag. Below are several key elements to consider:
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1. Base Material
At Mechanical Products (MP), we use high-temperature thermoplastics that resist cracking and are recyclable. In contrast, some manufacturers use thermoset materials, which are more prone to cracking and are not recyclable.

2. Contact Attachment
MP employs a permanent resistance welding process to bond the lifter and contact to the bimetal. This ensures a secure, long-lasting connection. Many other manufacturers use loose rivet contacts, which can weaken over time and reduce the circuit's protective performance.

3. Bimetal Source
We exclusively use validated U.S.-sourced bimetal, trusted for decades in both military and industrial applications. In contrast, bimetal sourced from China often lacks long-term performance validation.

4. Bimetal Staking
MP secures the bimetal to the stud/terminal through a permanent staking process, which minimizes resistance. Other manufacturers may use a threaded stud and nut design that can loosen over time, increasing heat and resistance, and thereby compromising protection.

5. Bimetal Contacts
MP products feature large, welded contacts that offer a greater contact area and more silver content, which helps prevent tarnishing. On the other hand, some imported breakers use rivet-style contacts with less silver, making them more susceptible to tarnish and reduced conductivity.

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MP engineers are experienced in testing to a wide range of standards, including UL, CSA, IEC, CCC, ABYC, SAE, and Mil-Spec, ensuring comprehensive circuit protection and environmental compliance.

We are committed to quality—and, more importantly, to your safety. A circuit breaker should not only meet the specifications provided by the manufacturer but also comply with applicable industry standards.

Reach out to your local distributor or MP sales representative today and discover the MP difference.

email: helpme@mechprod.com

Tariffs on the rise - Mechanical Products Made in the USA

kstrangeway@mechprod.com (Karie Strangeway) — Thu, 27 Feb 2025 17:17:41 GMT

Increasing Tariffs - Benefits of US Manufacturing

Since the 1940s, Mechanical Products (MP) has been a trailblazer in the manufacture of high-quality circuit protection solutions to both industrial and aerospace sectors. Visit our Products Page.

As the new millennium dawned, MP strategically divested its aerospace assets to sharpen its focus on the industrial manufacturing landscape. Faced with rising competition and the trend of offshoring in the early 2000s, MP adapted by relocating its manufacturing overseas.

However, in a bold move in 2013, MP reignited its commitment to American manufacturing by reshoring key products and launching innovative DC Circuit Protection solutions for the truck, bus, RV, military, specialty vehicle and off-road industries, proudly designed and manufactured on US soil.

Today, MP stands as the sole US manufacturer of these essential products, championing domestic production. Our achievements are a testament to our dedication, featuring groundbreaking series and unique features that are proven in demanding applications over the last 10+ years. Find datasheets

By producing approximately 80% of our goods within the country of use, MP has achieved a remarkable milestone over the past 14 years. Find a distributor

Amidst the evolving landscape of tariffs, MP stands uniquely poised to champion US manufacturing with our select series of American-made products. As the sole US-based producer of DC Circuit Protection Products in our field, we proudly set ourselves apart from competitors stationed in Mexico and Asia.

To foster new partnerships and delight our customers, we invite you to experience our complimentary sample program, complete with enhanced 2-3 day turn around.

Reach out to your local distributor or MP sales representative today and discover the MP difference. email: helpme@mechprod.com

Mechanical Products Series 87 Marine Rated Switchable Circuit Breaker

kstrangeway@mechprod.com (Karie Strangeway) — Thu, 23 Mar 2023 14:38:37 GMT

Switchable Heavy Duty Marine Rated

UL Circuit Breaker Standards Comparison – UL 489 vs. UL 1077

kstrangeway@mechprod.com (Karie Strangeway) — Thu, 16 Jun 2022 12:00:00 GMT

There are a great many circuit protection specifications and specification writing agencies that have an impact on the manufacturer and user. They range from the U.S. military to international agencies like IEC. Key specifications are regulatory agency Underwriters Laboratories’ (UL) Standards for Safety for low-voltage overcurrent protection devices. The differences in UL services related to circuit protection devices and the requirements and test parameters of UL 489 – the standard for Molded-Case Circuit Breakers, and UL 1077 – the standard for Supplementary Protectors for Use in Electrical Equipment are compared.

Get the full technical brief here

What is Trip-Free and Why do I need it?

kstrangeway@mechprod.com (Karie Strangeway) — Mon, 24 Jan 2022 13:00:00 GMT

A Trip-Free circuit breaker / supplementary protector is one that will trip open even if the ON-OFF mechanism is held in the ON position. This is an important characteristic of a circuit breaker as it protects humans and equipment from the hazards of overcurrent. If a breaker is tripping, it is doing its job. When its not doing its job wires can overheat and start fires, motors can burn out, people can be seriously injured. Read further for a more in-depth explanation.

Where MP "Legendary Performance" began

Larry Bajorek — Tue, 09 Mar 2021 13:45:00 GMT

We do not make mousetraps, but like the perfect mousetrap, the basic design, superior specifications and calibration range of the MP Series 16 has remained largely unchanged for over 75 years.

Eddy Currents

kstrangeway@mechprod.com (Karie Strangeway) — Thu, 11 Feb 2021 15:30:00 GMT

The production of magnetic flux is instantaneously proportional to the coil current i. Many of the principles outlined here are based on Mechanical Products’ published work, The Theory and Practice of Overcurrent Protection (1987). Strictly speaking, this is only true for magnetic circuits which do not contain any electrically conductive magnetic flux paths. When the level of magnetic flux changes (i.e. is raised or lowered) in a path/medium which can also conduct electric current, such as iron, there will arise, by Faraday’s Law, circulating eddy currents.

YEAR IN REVIEW

kstrangeway@mechprod.com (Karie Strangeway) — Mon, 11 Jan 2021 15:00:53 GMT

In this year of global challenges, Mechanical Products, and its valuable business partners, worked together to continue their mission to provide high quality thermal protection devices that are designed and manufactured to offer a competitive advantage with a commitment to meeting on-time delivery, and continuous improvement while doing so safely.

Mechanical Products Series 53 Branch Disconnect Circuit Breaker

kstrangeway@mechprod.com (Karie Strangeway) — Tue, 29 Sep 2020 20:17:05 GMT

DISCONNECT & PROTECT

LOMBARD, IL – Mechanical Products (MP) is pleased to announce the release of its newest circuit protection device, the SERIES 53 BRANCH DISCONNECT CIRCUIT BREAKER.

Arcs in Circuit Breakers

kstrangeway@mechprod.com (Karie Strangeway) — Mon, 27 Jul 2020 18:31:10 GMT

A contact arc in a circuit breaker is an extremely complex electro-thermo-hydro-dynamic process and that we never fully mathematically describe the detailed physics of an arc. Many of the principles outlined here are based on Mechanical Products’ published work, The Theory and Practice of Overcurrent Protection (1987). Our goal, here, is to develop an approximate arc model such that we can treat an arc as a circuit element, and analyze electric circuits containing arcs.