Circuit Breakers University City San Diego – New & Used Breakers, Panels & Electrical Supplies

Electrical Supplies Unlimited (ESU) is your trusted source for Circuit Breakers in University City San Diego, serving contractors, electricians, property managers, and homeowners throughout University City and surrounding communities including University Heights, Hillcrest, Golden Hill, Bankers Hill, and greater San Diego County.

We buy and sell both new and used circuit breakers, electrical panels, transformers, and electrical equipment. Whether you need replacement breakers, obsolete breakers, or hard-to-find electrical components, ESU provides dependable solutions backed by over 40 years of industry experience.

San Diego’s Trusted Circuit Breaker Supplier Since 1985

ESU has proudly served the San Diego electrical supply industry for more than four decades. As a fully stocked electrical distributor and wholesaler, we carry a wide range of residential, commercial, and industrial electrical supplies designed to meet virtually any project requirement.

Our experienced team specializes in locating discontinued, surplus, and specialty electrical products, helping customers source reliable solutions quickly and efficiently.

Leading Circuit Breaker Brands Available

Our extensive inventory includes major circuit breaker manufacturers and trusted industry brands, including:

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

Complete Electrical Supply Inventory

In addition to circuit breakers, ESU stocks a large inventory of:

• 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 & Residential Electrical Supplies

We also offer Greenlee tool rentals, conduit benders, wire pullers, and additional electrician equipment for contractors throughout San Diego County.

Specialists in New, Used & Obsolete Circuit Breakers

ESU is San Diego’s go-to source for new, used, surplus, and obsolete circuit breakers. We carry a broad range of amperages and voltages for nearly every major electrical system.

Examples of our inventory include:

• 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

Whether you need residential breaker replacements, commercial electrical upgrades, or industrial breaker solutions, our knowledgeable staff can help you select the right product for your project.

Serving University City & Greater San Diego

We proudly provide circuit breakers and electrical supplies throughout:

• Allied Gardens
• Hillcrest
• Golden Hill
• Bankers Hill
• University Heights
• Vista
• Oceanside
• Carlsbad
• San Marcos
• All San Diego County

We also ship many products nationwide for customers outside the San Diego region.

Your Local Circuit Breaker Experts

At Electrical Supplies Unlimited, we combine decades of electrical supply expertise with one of the region’s most diverse inventories of circuit breakers and electrical equipment.

Whether you’re replacing outdated breakers, sourcing specialty equipment, or upgrading electrical infrastructure, ESU delivers dependable products, expert guidance, and exceptional customer service.

Call ESU today at 858.558.2850 to speak directly with one of our electrical supply specialists and find the right circuit breaker or electrical solution for your needs.

Electrical Panel Replacement San Diego

Electrical panel replacement is one of the most important upgrades you can make to improve the safety, reliability, and capacity of your electrical system. Whether you're renovating an older home, upgrading a commercial property, or replacing a damaged panel, understanding when and why to replace an electrical panel can help prevent costly electrical problems and improve overall system performance.

This guide explains common reasons for electrical panel replacement, signs of panel failure, upgrade considerations, and how to select the right panel and circuit breakers for your San Diego property.

When Is Electrical Panel Replacement Necessary?

Electrical panels are designed to safely distribute electricity throughout a building, but older panels may no longer meet modern electrical demands. As homes and businesses add new appliances, air conditioning systems, EV chargers, computers, and other equipment, electrical panels can become overloaded.

Common signs that indicate you may need an electrical panel replacement include:

• Frequently tripping circuit breakers
• Flickering or dimming lights
• Burning smells near the panel
• Rust, corrosion, or water damage
• Outdated Federal Pacific (FPE), Zinsco, or Challenger panels
• Insufficient capacity for new electrical equipment

Learn more in our guide on When to Upgrade Your Electrical Panel.

Benefits of Replacing an Electrical Panel

A new electrical panel offers several advantages beyond simply replacing aging equipment.

• Improved electrical safety
• Increased electrical capacity
• Reduced risk of breaker failure
• Support for modern appliances and technology
• Better compliance with current electrical codes
• Enhanced property value

Modern electrical panels also provide greater flexibility for future expansion and additional circuits.

Common Electrical Panel Sizes

Today's residential electrical systems commonly utilize:

• 100 Amp Panels
• 125 Amp Panels
• 150 Amp Panels
• 200 Amp Panels
• 225 Amp Panels
• 400 Amp Service Panels

The proper panel size depends on the building's electrical load requirements and future expansion plans.

Replacing Obsolete Electrical Panels

Many older homes throughout San Diego still contain obsolete electrical panels that are no longer considered ideal for modern electrical systems. Some of the most common examples include:

• Federal Pacific (FPE) Panels
• Zinsco Panels
• Challenger Panels
• Pushmatic Panels

These older systems often present challenges when replacement breakers are needed and may not provide the level of protection expected from modern equipment.

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

Choosing the Right Circuit Breakers for Your New Panel

Electrical panel replacement often involves installing new circuit breakers that are compatible with the upgraded panel. Selecting the proper breakers ensures reliable operation and compliance with manufacturer specifications.

Common breaker manufacturers include Siemens, Square D, Eaton, Cutler Hammer, General Electric (GE), and others.

For additional guidance, visit our How to Choose the Right Circuit Breaker resource.

Electrical Panel Replacement Cost

The cost of electrical panel replacement varies depending on several factors, including panel size, service capacity, breaker requirements, wiring upgrades, and local installation conditions.

Projects involving service upgrades, additional circuits, or commercial electrical systems typically require larger investments than standard residential panel replacements.

Learn more in our guide on Circuit Breaker Panel Upgrade Cost.

Circuit Breakers and Electrical Panels in San Diego

Electrical Supplies Unlimited carries a large inventory of circuit breakers, electrical panels, transformers, disconnects, and electrical equipment for residential, commercial, and industrial applications throughout San Diego County.

Whether you need replacement breakers, a complete panel upgrade, or hard-to-find electrical components, our experienced team can help you identify the right solution for your project.

Why Electrical Panel Upgrades Are Increasing in San Diego

Many San Diego property owners are upgrading electrical panels to accommodate electric vehicle chargers, solar energy systems, air conditioning upgrades, home additions, and modern electrical equipment. These improvements often require additional electrical capacity that older panels cannot provide.

Upgrading your electrical panel can improve system performance while helping prepare your property for future electrical demands.

More Circuit Breaker & Electrical Panel Resources

• Circuit Breaker Resource Hub
• Circuit Breakers San Diego
• Circuit Breaker Replacement Guide
• When to Upgrade Your Electrical Panel
• Circuit Breaker Panel Upgrade Cost
• Buy Circuit Breakers San Diego

Medium Voltage Circuit Breakers: Industrial Power Protection

Medium voltage circuit breakers are designed to protect electrical systems operating between approximately 1,000 volts and 38,000 volts. These breakers are commonly used in industrial facilities, power distribution systems, substations, and large commercial buildings.

Because these systems handle large electrical loads, medium voltage breakers must provide reliable fault protection while maintaining safe operation under demanding conditions.

What Is a Medium Voltage Circuit Breaker?

A medium voltage circuit breaker is designed to interrupt high electrical currents caused by faults such as short circuits, overloads, or equipment failure. These breakers protect expensive equipment and help prevent major electrical damage or downtime.

Medium voltage breakers are typically installed in:

• Electrical substations
• Industrial manufacturing facilities
• Large commercial buildings
• Utility power distribution systems
• Data centers and infrastructure facilities

Types of Medium Voltage Circuit Breakers

Vacuum Circuit Breakers

Vacuum breakers use sealed vacuum interrupters to extinguish electrical arcs during fault interruption. They are widely used in modern medium voltage systems because of their reliability and low maintenance requirements.

SF6 Gas Circuit Breakers

SF6 circuit breakers use sulfur hexafluoride gas to extinguish electrical arcs. These breakers are commonly used in high-power industrial applications where large fault currents must be interrupted safely.

Air Circuit Breakers

Air circuit breakers use compressed air to extinguish electrical arcs. Although less common in modern systems, they are still used in certain industrial and legacy installations.

Applications of Medium Voltage Breakers

Medium voltage breakers play a critical role in large-scale electrical systems, protecting equipment such as:

• Power transformers
• Industrial motors
• Distribution feeders
• Switchgear systems
• Utility infrastructure

These breakers help maintain system stability and reduce the risk of costly equipment damage.

Maintenance and Safety

Because medium voltage systems carry significant electrical energy, routine inspection and maintenance are essential. Electrical professionals typically perform testing, insulation checks, and infrared inspections to identify potential issues before failures occur.

Explore More Circuit Breaker Resources

For more information about selecting, troubleshooting, and replacing circuit breakers, visit our Circuit Breaker Resource Hub. Our guides provide practical insights for electricians, contractors, and facility managers.

Learn More About Circuit Breakers

To explore additional resources about circuit breaker types, safety tips, and troubleshooting, visit our Circuit Breaker Resource Hub. Our guides help electricians, contractors, and homeowners understand how to maintain safe electrical systems.

Explore Our Circuit Breaker Guides & Resources

Below is our growing library of circuit breaker guides designed to help homeowners, electricians, and contractors understand electrical safety, breaker selection, and troubleshooting.

• How to Choose the Right Circuit Breaker
• Why Your Circuit Breaker Keeps Tripping
• Best Circuit Breaker Brands: Complete Comparison
• How to Replace FPE, Zinsco, or Challenger Breakers
• Residential Circuit Breaker Safety Tips
• Low Voltage Circuit Breakers Explained
• Medium Voltage Circuit Breakers Explained

Visit our Circuit Breaker Resource Hub to explore more information about breaker types, electrical safety, and selecting the right circuit protection for your project.

Circuit Breakers in National City, San Diego. ESU buys and sells new & used Breakers and Panels!

Electrical Supplies Unlimited buys and sells new & used Circuit Breakers in National City  San Diego surrounding areas including Chula Vista, Imperial Beach, Bonita, Rancho Del Rey, Terra Nova, Eastlake Greens and many more. Of course, we can arrange shipment on a wide variety of products to service those outside our area. We will also buy your used Transformers.

ESU Inc. has proudly served the electrical supply industry for over 40 years. We offer an extensive selection of new, surplus, and recycled electrical supplies to meet both residential and commercial needs. As a fully stocked electrical distributor and wholesaler, we carry a wide range of product lines and specialize in sourcing hard-to-find items. Our knowledgeable team is dedicated to exceeding customer expectations, and our long-standing reputation speaks for itself. Call us at 858.558.2850 to experience our service firsthand.

Our inventory features products from many leading manufacturers, including General Electric, Hammond Power, ITE Siemens, Cutler Hammer, Square D, FPE Federal Pacific, Pushmatic, Zinsco, Crouse-Hinds, Challenger, Westinghouse, Sylvania, and Bryant.

We stock a broad selection of electrical equipment, including circuit breakers, transformers, disconnects, panelboards up to 600V, fuses up to 3000 amps, bolt switch pullouts, motor starters and relays, meter sockets, lighting ballasts, and metal halide and SOX bulbs. ESU also carries Lithonia commercial and residential lighting fixtures.

ESU supplies a diverse range of electrical products to fit virtually any application or budget, serving customers throughout San Diego County as well as intra- and interstate clients. In addition, we rent Greenlee wire pullers, conduit benders, and other professional electrician tools. For personalized assistance, speak directly with one of our specialists—Scott, Kevin, or Chris. Call 858.558.2850 today and let ESU serve your electrical supply needs.

Circuit Breakers Electrical Supplies Unlimited sells and buys both new and used Circuit Breakers, serving Circuit Breakers to National City, San Diego and nearby areas such as Chula Vista, Bonita, Rancho Del Rey, Terra Nova and more. We can also arrange shipment of many products to serve customers outside the region. In addition, we will purchase your used Transformers, Breakers, Panels and most Electrical Supplies.

We handle most of the major brands, including Westinghouse, Acme, Cutler Hammer, ITE Siemens, Federal Pacific (FPE), Square D, General Electric, and Zinsco. As a fully stocked Electrical Distributor and Wholesaler, we keep many different product lines readily available.

Electrical Supplies Unlimited is San Diego’s go-to source for Circuit Breaker electrical supplies. Our inventory includes a wide range of circuit breakers across most voltages and amperages. In our San Diego store, we carry products from many manufacturers such as Zinsco, Federal Pacific (FPE), Pushmatic, Bulldog, Cutler Hammer, ITE Siemens, Square D, and more. We stock most amperages and voltages. Some examples of what we offer:

20 Amp thru 125 amp Zinsco breakers
20 amp through 1200 amp 480 volt Siemens breakers 3 phase and single phase
15 thru 100 amp 120/240 Volt Pushmatic Breakers
15 thru 1200 amp 120/240 and 480V Federal Pacific FPE circuit breakers

We are circuit breakers and electrical hardware experts. Do not hesitate to call us at 858.558.2850 to find out which Circuit Breaker is right for your requirement.

Your one stop go to guys. Always at your service!