
Electrical Supplies Unlimited buys and sells new & used Circuit Breakers in Terra Nova San Diego surrounding areas including Chula Vista, Bonita, Rancho Del Rey, Eastlake Greens, Sunbow 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 more than 40 years. We carry a wide selection of new, surplus, and recycled electrical supplies for both residential and commercial needs. As a fully stocked Electrical Distributor and Wholesaler, we maintain many different product lines on hand. We specialize in locating hard-to-find items, and our experienced staff is committed to going above and beyond customer expectations. Our reputation speaks for itself—just ask around, or give us a call at 858.558.2850 to experience it firsthand.
Our inventory includes most leading brands such as General Electric, Hammond Power, ITE Siemens, Cutler Hammer, Square D, FPE Federal Pacific, Pushmatic, Zinsco, Crouse Hinds, Challenger, Westinghouse, Sylvania, and Bryant.
Our inventory consists of a large selection of Circuit Breakers, Transformers, Disconnects, Panelboards to 600v, Fuses up to 3000 Amps, Bolt Switch Pullouts, Motor Starters and Relays, Meter sockets, Lighting ballasts, Metal Halide and Sox bulbs. We also carry Lithonia Commercial and residential lighting fixtures as well.
Our Products ESU sells a large and diverse inventory of Electrical Supplies, Electrical Equipment, including Circuit Breakers, Fuses, Transformers, Panelboard switches, Safety switches, Fuseable switches, Meter Sockets, Motor Controllers, Lighting Ballasts, Bolt switch and much more. We carrier almost all manufacturers including Zinsco, Pushmatic, FPE Federal Pacific, ITE Siemens, Cutler Hammer, Lutron, Lithonia,, Square D, Challenger and many more. We serve the San Diego and SD County areas and to many other intra and interstate clients. We sell products to fit any requirement or budget. ESU rents Greenlee Wire Pullers, Conduit benders as well as other electrician tools. Talk directly to one of our specialists, Scott, Kevin or Chris to find out more. So give us a call today at 858.558.2850 and let us serve you
Circuit Breakers Electrical Supplies Unlimited sells and buys both new and used Circuit Breakers, serving Circuit Breakers to Terra Nova, San Diego and nearby areas such as Chula Vista, Bonita, Rancho Del Rey, Eastlake Greens, Sunbow, 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!

Electrical Supplies Unlimited buys and sells new & used Circuit Breakers in Otay Ranch San Diego surrounding areas including Chula Vista, Imperial Beach, Bonita, 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 San Ysidro, 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!
Upgrading your electrical panel is one of the most important improvements you can make to your home’s electrical system. If you're researching circuit breaker panel upgrade cost, you're likely trying to understand pricing, safety benefits, and whether an upgrade is necessary.
Electrical panel upgrades improve safety, increase electrical capacity, and ensure your system can handle modern appliances, HVAC systems, and technology. This guide explains typical costs, what factors affect pricing, and when a panel upgrade is recommended.
Average Circuit Breaker Panel Upgrade CostThe cost to upgrade a circuit breaker panel typically ranges from $1,500 to $4,000 for most residential homes. However, more complex installations or larger service upgrades can cost between $4,000 and $8,000 or more.
The total cost depends on several factors, including the size of the panel, electrical capacity, labor requirements, and whether additional upgrades are needed.
Upgrading from a 100-amp panel to a 200-amp panel is one of the most common residential upgrades. Larger service capacities require more materials and labor, increasing overall cost.
If the electrical panel is difficult to access or needs to be relocated, labor costs may increase. Panels located in garages or exterior walls are typically easier to upgrade than those in tight indoor spaces.
Older homes may require additional wiring upgrades to meet current electrical codes. Replacing outdated wiring or adding new circuits can increase the total project cost.
Most panel upgrades require permits and inspections to ensure the work meets local electrical codes. Permit costs vary by location but are an important part of a safe and compliant installation.
Some homeowners upgrade their panel to support new appliances, electric vehicle chargers, or home additions. These upgrades may require additional circuits, subpanels, or service upgrades.
If you are unsure whether a panel upgrade is necessary, look for these common warning signs:
These issues may indicate that your current panel is overloaded or outdated.
Upgrading your electrical panel provides several important benefits:
For most homeowners, upgrading an outdated electrical panel is a worthwhile investment. It improves safety, increases home value, and ensures your electrical system can meet current and future demands.
If your panel is older or frequently experiencing issues, upgrading can prevent costly repairs and reduce the risk of electrical hazards.
To better understand breaker selection, safety, and troubleshooting, visit our Circuit Breaker Resource Hub.
You can also read our guides on how to choose the right circuit breaker and signs of a bad circuit breaker.
Finding obsolete circuit breakers can be challenging, especially when dealing with older electrical panels that are no longer manufactured. Many homes, commercial buildings, and industrial facilities still rely on discontinued breaker systems, making replacement parts difficult to locate through traditional electrical supply channels.
Fortunately, many obsolete circuit breakers are still available through specialty electrical suppliers. Understanding your options can help you maintain electrical safety, avoid costly downtime, and extend the life of your electrical system.
What Are Obsolete Circuit Breakers?Obsolete circuit breakers are breakers that are no longer manufactured by the original company. Although production may have ended years ago, many of these breakers remain in service throughout homes, office buildings, apartment complexes, manufacturing facilities, and commercial properties.
In many cases, replacement breakers are still available as new surplus, reconditioned, or professionally tested used inventory.
Some of the most frequently requested obsolete circuit breaker brands include:
Many of these systems were installed decades ago and continue operating today, creating ongoing demand for replacement breakers and panel components.
Replacing an entire electrical panel is not always practical or immediately necessary. Property owners often seek obsolete breakers when:
Locating the correct replacement breaker can often save significant time and expense compared to a complete panel replacement.
Federal Pacific Electric (FPE) breakers are among the most commonly requested obsolete circuit breakers. While many FPE panels remain in service, replacement breakers can be difficult to locate through standard electrical distributors.
Property owners frequently search for replacement FPE Stab-Lok breakers when maintaining older electrical systems.
Learn more in our guide on Replacing FPE, Zinsco, and Challenger Breakers.
Zinsco electrical panels were widely installed throughout the United States and are still found in many older residential and commercial properties. Because original Zinsco equipment is no longer manufactured, replacement breakers often require sourcing from specialty electrical suppliers.
Electrical contractors frequently encounter Zinsco systems during remodeling, panel upgrades, and electrical inspections.
Challenger breakers remain common in many buildings constructed during the 1980s and 1990s. While some Challenger products were later absorbed into other product lines, finding exact replacement breakers often requires access to surplus or obsolete inventory.
Many electricians seek Challenger replacements when repairing existing electrical systems or upgrading service equipment.
Circuit breakers should be replaced whenever they show signs of failure or damage. Common warning signs include:
If you notice any of these symptoms, review our guide on Signs of a Bad Circuit Breaker.
In some situations, replacing a single obsolete breaker is the most practical solution. In others, a complete electrical panel upgrade may offer greater safety, capacity, and long-term reliability.
Factors to consider include:
Learn more in our guide on When to Upgrade Your Electrical Panel.
Electrical Supplies Unlimited specializes in locating new, used, surplus, and obsolete circuit breakers throughout San Diego County. Our inventory includes hard-to-find breakers, discontinued models, legacy panel components, and replacement electrical equipment for residential, commercial, and industrial applications.
We help contractors, electricians, property managers, and facility maintenance professionals locate difficult-to-find breakers quickly and efficiently.
With over 40 years of experience serving the electrical industry, ESU has built a reputation as one of San Diego's trusted sources for obsolete electrical equipment. Our extensive inventory and product knowledge allow us to help customers locate replacement breakers that many suppliers no longer carry.
Whether you need a discontinued FPE breaker, Zinsco replacement, Challenger breaker, or another hard-to-find model, our team can help identify the correct solution.
High-voltage circuit breakers are designed to protect electrical systems operating at significantly higher voltages than standard residential or commercial circuits. These breakers are commonly used in utility systems, industrial facilities, and large-scale power distribution networks where reliable interruption of high-energy electrical flow is critical.
The primary function of a high-voltage circuit breaker is to safely interrupt electrical current during fault conditions such as overloads or short circuits. Because high-voltage systems carry much greater energy, these breakers are engineered with advanced arc-quenching technology to prevent equipment damage and reduce safety risks.
High-voltage systems require precise engineering and strict safety compliance. Proper breaker selection ensures system stability, prevents equipment failure, and reduces the risk of electrical hazards. Regular inspection and maintenance are essential in high-voltage environments.
Explore more circuit breaker topics and San Diego electrical solutions: