Electrical Supplies Unlimited supplies a large stock of  Medium Voltage Circuit Breakers (5-27kV).

Electrical Supplies Unlimited is your trusted source for high-quality medium voltage circuit breakers designed to protect critical electrical systems in commercial, industrial, and utility applications. Medium voltage systems typically operate in the range of 1,000 volts (1kV) up to 35,000 volts (35kV), making these breakers essential for substations, industrial facilities, data centers, and power distribution infrastructure. Our extensive inventory of medium voltage circuit breakers includes proven models from industry-leading manufacturers, ensuring reliable performance, long service life, and compliance with modern electrical standards.

Unlike low-voltage breakers rated at 600 volts and below, medium voltage circuit breakers are engineered to handle higher fault currents and more demanding operating environments. They play a critical role in protecting transformers, switchgear, and distribution equipment by safely interrupting overloads and short circuits before damage occurs. At Electrical Supplies Unlimited, we specialize in supplying dependable medium voltage circuit breakers that balance performance, durability, and cost-effectiveness—helping contractors, engineers, and facility managers maintain safe, efficient, and resilient power systems.

Electrical Supplies Unlimited is also a go-to source for high-quality medium-voltage circuit breakers (5-27kV), offering reliable solutions for industrial, commercial, and utility applications. Our extensive selection of medium-voltage circuit breakers ensures optimal performance, safety, and durability for power distribution systems. Whether you're upgrading an existing system or installing a new one, our expert team is here to guide you toward the best solutions for your electrical needs. With a commitment to superior quality and customer satisfaction, Electrical Supplies Unlimited is the trusted supplier for businesses looking for top-tier circuit breakers in the industry.

One key distinction between medium-voltage and low-voltage circuit breakers is their capacity and application. While low-voltage circuit breakers (typically rated below 1,000V) are designed for residential and commercial electrical panels, medium-voltage circuit breakers (ranging from 5-27kV) are essential for large-scale power distribution, industrial plants, and substations. Medium-voltage breakers are built to handle higher fault currents and provide enhanced arc flash protection, ensuring greater reliability in high-power environments. At Electrical Supplies Unlimited, we provide top-of-the-line medium-voltage circuit breakers tailored to your specific power needs, ensuring efficiency, safety, and long-term durability.

GE
Westinghouse-Cutler-Hammer
Siemens-Allis Chalmers
ABB-BBC-ITE-Gould
Federal Pacific
Square D

We will buy new and used Low & Medium Voltage Breakers

ESU Electrical Supplies Unlimited not only sells top-quality electrical components, but also buys both new and used equipment, including low and medium voltage circuit breakers. Whether you’re upgrading your system or decommissioning old gear, ESU offers a convenient solution by purchasing your surplus breakers and electrical parts. This helps reduce waste and puts valuable equipment back into circulation for future use.

Circuit Breaker Compatibility Guide: Matching Breakers to Electrical Panels

One of the most common questions electricians, contractors, and property owners ask is: "What circuit breaker is compatible with my electrical panel?" Choosing a compatible circuit breaker is critical for electrical safety, reliable performance, and compliance with manufacturer specifications.

Installing the wrong breaker can lead to poor connections, nuisance tripping, equipment damage, and potential safety hazards. This guide explains circuit breaker compatibility, how to identify the correct replacement breaker, and what to consider when working with both modern and obsolete electrical panels.

Why Circuit Breaker Compatibility Matters

Circuit breakers are designed and tested to work with specific electrical panels. Even if two breakers appear physically similar, they may not be approved for use in the same panel.

Electrical panel manufacturers engineer breakers to match the panel's bus bars, mounting systems, electrical characteristics, and safety certifications.

Using an incompatible breaker may:

• Create loose electrical connections
• Cause overheating
• Lead to nuisance tripping
• Void equipment listings
• Create code compliance issues
• Increase electrical safety risks

How to Identify the Correct Replacement Breaker

Before purchasing a replacement breaker, identify the following information:

• Panel manufacturer
• Panel model number
• Breaker amperage rating
• Breaker type
• Voltage requirements
• Number of poles

The panel label often provides important compatibility information and manufacturer recommendations.

If you're unsure which breaker you need, review our How to Choose the Right Circuit Breaker guide.

Siemens Circuit Breaker Compatibility

Siemens circuit breakers are among the most widely used breakers in residential and commercial electrical systems. Siemens manufactures a variety of breaker types and panel configurations.

Replacement breakers should always match the specific Siemens panel series and electrical requirements.

Learn more in our Siemens vs Square D Circuit Breakers comparison guide.

Square D Circuit Breaker Compatibility

Square D panels typically utilize either Homeline or QO series breakers. These product lines are not interchangeable and require matching breaker types designed specifically for the panel.

Square D breakers remain one of the most commonly requested replacement breaker products in both residential and commercial applications.

Eaton and Cutler Hammer Compatibility

Eaton and Cutler Hammer breakers are commonly found throughout residential, commercial, and industrial installations. Many legacy Cutler Hammer systems have transitioned into Eaton product lines, but compatibility should always be verified before installation.

Matching the correct breaker type is essential for proper operation and safety.

General Electric (GE) Circuit Breakers

General Electric electrical panels have been widely installed for decades. Depending on the age and model of the panel, replacement breaker options may vary significantly.

When replacing GE breakers, verify both the breaker model and panel compatibility before purchasing replacement components.

Federal Pacific (FPE) Compatibility

Federal Pacific Electric (FPE) Stab-Lok panels remain common in older residential and commercial buildings. Finding compatible replacement breakers can be challenging because many original products are no longer manufactured.

Property owners often seek replacement FPE breakers through specialty electrical suppliers that carry surplus and obsolete inventory.

Learn more in our guide on Replacing FPE, Zinsco, and Challenger Breakers.

Zinsco Circuit Breaker Compatibility

Zinsco electrical panels remain in service throughout many older properties. Since original Zinsco breakers are no longer manufactured, identifying compatible replacements often requires specialized product knowledge.

Many electricians seek replacement breakers for Zinsco systems during renovations and electrical upgrades.

Challenger Circuit Breaker Compatibility

Challenger panels were installed in many residential and commercial properties during the 1980s and 1990s. While some Challenger product lines were absorbed into other manufacturers, compatibility varies depending on the panel model and breaker type.

Proper identification is important when sourcing replacement breakers for Challenger systems.

Can You Use a Different Brand Circuit Breaker?

Some manufacturers offer classified breakers that have been tested and approved for use in certain competing panel brands. However, not all breakers are interchangeable, and assumptions should never be made based solely on appearance.

Always verify:

• Manufacturer approvals
• UL classifications
• Panel labeling requirements
• Electrical code requirements

When in doubt, consult the panel manufacturer or an experienced electrical supplier.

Compatibility and Obsolete Circuit Breakers

Compatibility becomes even more important when working with obsolete electrical equipment. Many discontinued panels require specific replacement breakers that may only be available through surplus, reconditioned, or specialty inventory sources.

Learn more in our guide on Obsolete Circuit Breakers.

When Should You Replace the Entire Electrical Panel?

In some cases, locating compatible breakers becomes increasingly difficult as electrical systems age. If replacement parts are unavailable or your electrical needs have outgrown the panel, a complete electrical panel replacement may be the best long-term solution.

Learn more in:

• Electrical Panel Replacement San Diego
• When to Upgrade Your Electrical Panel
• Circuit Breaker Panel Upgrade Cost

Finding Compatible Circuit Breakers in San Diego

Electrical Supplies Unlimited carries a large inventory of new, surplus, used, and obsolete circuit breakers for residential, commercial, and industrial applications. Our team can help identify compatible breakers for many major manufacturers, including Siemens, Square D, Eaton, Cutler Hammer, GE, Federal Pacific, Challenger, Zinsco, Pushmatic, and more.

Whether you're replacing a single breaker or maintaining an older electrical system, we can help you locate the right solution.

More Circuit Breaker Resources

• Circuit Breaker Resource Hub
• Circuit Breakers San Diego
• How to Choose the Right Circuit Breaker
• Siemens vs Square D Circuit Breakers
• Obsolete Circuit Breakers
• Circuit Breaker Replacement Guide
• Buy Circuit Breakers San Diego

Residential Circuit Breaker Safety Tips for Homeowners

Residential circuit breakers are designed to protect your home’s electrical system from dangerous overloads and short circuits. When working properly, a breaker automatically shuts off power when electrical current exceeds safe levels, preventing fires, damaged appliances, and serious electrical hazards.

Understanding residential circuit breaker safety is essential for homeowners, property managers, and electricians. Knowing how to recognize warning signs and follow basic home electrical safety tips can help prevent costly repairs and protect your family.

Why Circuit Breaker Safety Matters in Homes

Your electrical panel distributes electricity throughout your home. Each circuit breaker protects a specific circuit by stopping electrical flow when a problem occurs. Without properly functioning breakers, overloaded circuits could overheat wiring and potentially start electrical fires.

Following proper electrical panel safety practices helps ensure your system remains reliable and compliant with modern electrical standards.

Never Overload Electrical Circuits

One of the most common causes of breaker trips is circuit overload. This occurs when too many appliances draw power from the same circuit at the same time.

High-power devices such as space heaters, microwaves, hair dryers, and portable air conditioners can quickly exceed a circuit's capacity. Spreading appliances across different outlets and circuits helps prevent overload conditions.

Do Not Ignore Frequently Tripping Breakers

A breaker that trips occasionally may simply indicate temporary overload. However, breakers that trip repeatedly may signal a more serious electrical issue such as damaged wiring, faulty appliances, or a failing breaker.

If you experience frequent breaker trips, it's important to investigate the cause rather than repeatedly resetting the breaker.

Keep Your Electrical Panel Accessible

Your breaker panel should always remain easily accessible in case power needs to be shut off quickly during an emergency. Avoid blocking the panel with furniture, storage boxes, or other household items.

Electrical panels should also be clearly labeled so each breaker can be quickly identified when troubleshooting a problem.

Watch for Warning Signs of Electrical Problems

Several warning signs may indicate a circuit breaker or electrical panel issue:

• Burning smells near the electrical panel
• Warm or hot breaker switches
• Flickering lights throughout the home
• Breakers that will not stay reset
• Buzzing or crackling sounds from the panel

If any of these symptoms occur, the breaker or wiring may require professional inspection.

Replace Outdated or Unsafe Breakers

Some older electrical panels contain breakers that are now considered unsafe or unreliable. Brands such as FPE Stab-Lok, Zinsco, and certain Challenger panels have been associated with failure to trip during electrical faults.

Replacing outdated breakers with modern, code-compliant components greatly improves residential electrical safety.

When to Call an Electrician

While homeowners can safely reset a breaker, electrical repairs and panel upgrades should always be performed by qualified professionals. Licensed electricians can diagnose wiring problems, replace faulty breakers, and ensure the system meets current electrical code requirements.

Learn More About Circuit Breakers

If you want to better understand breaker types, compatibility, and electrical system protection, explore our complete Circuit Breaker Resource Hub where we provide expert guidance for residential, commercial, and industrial applications.

For a complete overview of breaker types, brands, and electrical applications, visit our Circuit Breaker Resource Hub.

More Circuit Breaker Resources

• Circuit Breaker Resource Hub
• How to Choose the Right Circuit Breaker
• Low Voltage Circuit Breakers Explained
• Common Circuit Breaker Brands

Circuit Breakers Linda Vista San Diego – New & Used Breakers, Panels & Electrical Supplies

Electrical Supplies Unlimited (ESU) is your dependable source for Circuit Breakers in Linda Vista San Diego, serving electricians, contractors, businesses, and homeowners throughout Linda Vista, Mission Valley, Kearny Mesa, Clairemont, Serra Mesa, and surrounding San Diego communities.

We specialize in buying and selling new, used, surplus, and obsolete circuit breakers, electrical panels, transformers, and hard-to-find electrical components. Whether you need replacement breakers for residential repairs or industrial-grade electrical equipment, ESU offers over 40 years of trusted electrical supply experience.

Trusted San Diego Circuit Breaker Supplier for Over 40 Years

ESU has proudly served the San Diego electrical supply industry since 1985. As a fully stocked electrical distributor and wholesaler, we maintain an extensive inventory of circuit breakers and electrical supplies for residential, commercial, and industrial applications.

Our knowledgeable team specializes in locating difficult-to-find and discontinued products, helping customers throughout Linda Vista and San Diego source dependable electrical solutions quickly.

Major Circuit Breaker Brands Available

We stock products from most leading electrical manufacturers, including:

Siemens / ITE, General Electric (GE), Cutler Hammer, Square D, Federal Pacific (FPE), Pushmatic, Zinsco, Challenger, Bryant, Bulldog, Westinghouse, Sylvania, Crouse Hinds, Hammond Power, and many more.

Complete Electrical Supply Inventory

In addition to circuit breakers, our inventory includes:

• Transformers
• Panelboards up to 600V
• Disconnects & Safety Switches
• Fuses up to 3000 Amps
• Meter Sockets
• Motor Starters & Relays
• Lighting Ballasts & Fixtures
• Bolt Switch Pullouts
• Commercial and industrial electrical hardware

We also provide Greenlee wire pullers, conduit benders, and electrical contractor tools for local projects throughout San Diego County.

New, Used & Obsolete Circuit Breakers in San Diego

ESU is one of San Diego’s premier suppliers for circuit breakers across most amperages and voltages. We stock:

• 20 Amp to 125 Amp Zinsco breakers
• 15 Amp to 100 Amp Pushmatic breakers
• 20 Amp to 1200 Amp Siemens breakers
• 15 Amp to 1200 Amp Federal Pacific (FPE) breakers
• Single-phase and 3-phase commercial breakers

We also offer specialty solutions including tandem circuit breakers, panel upgrades, and breaker replacement solutions for outdated or discontinued systems.

Serving Linda Vista San Diego & Nearby Communities

We proudly serve customers throughout:

• Linda Vista San Diego
• Mission Valley
• Kearny Mesa
• Clairemont
• Serra Mesa
• Mira Mesa
• San Diego
• Vista
• Oceanside
• All San Diego County

We also ship electrical products nationwide for customers outside Southern California.

Circuit Breaker Resources & Electrical Expertise

Whether you need help selecting the correct breaker, replacing outdated panels, or sourcing commercial electrical equipment, ESU offers trusted expertise and one of the largest inventories in the region.

Helpful resources include:

• How to Choose the Right Circuit Breaker
• When to Upgrade Your Electrical Panel
• Circuit Breaker Panel Upgrade Cost
• Circuit Breaker Resource Hub

Your Linda Vista San Diego Circuit Breaker Experts

Electrical Supplies Unlimited combines deep product knowledge, decades of industry experience, and one of Southern California’s most diverse inventories of circuit breakers and electrical supplies.

Whether you are an electrician, contractor, property manager, or homeowner, ESU is your trusted source for circuit breakers in Linda Vista San Diego.

Call 858.558.2850 today to speak directly with one of our electrical supply specialists and find the right breaker, panel, or electrical solution for your project.