
Electrical Supplies Unlimited buys and sells new & used Circuit Breakers in Otay Ranch 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 Otay Ranch, 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!

Electrical Supplies Unlimited buys and sells new & used Circuit Breakers in Sunbow San Diego surrounding areas including Chula Vista, 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 Sunbow, 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!
A tandem circuit breaker is a special type of breaker that allows two separate circuits to be installed in a single slot within an electrical panel. These breakers are often used when a panel runs out of space but additional circuits are needed.
Understanding how tandem breakers work, when they are allowed, and whether they are safe is essential for homeowners, electricians, and contractors working with residential electrical systems.
What Is a Tandem Circuit Breaker?A tandem circuit breaker (sometimes called a “double” or “cheater” breaker) combines two individual breakers into one unit that fits into a single panel slot. Each circuit operates independently, providing the same protection as a standard single-pole breaker.
This allows an electrical panel to support more circuits without physically expanding the panel.
Tandem breakers are typically used when an electrical panel has no available space for additional circuits. Common situations include:
They provide a convenient solution when space is limited, but they are not always the best long-term option.
Yes, tandem circuit breakers are safe when used correctly and installed in panels that are specifically designed to accept them. Electrical panels have a maximum number of circuits they can safely handle, and tandem breakers should only be used within those limits.
Installing tandem breakers in a panel that is not rated for them can lead to overheating, code violations, and potential electrical hazards.
Tandem breakers are legal when used in accordance with the panel manufacturer’s specifications and local electrical codes. Most panels include labeling that indicates how many tandem breakers are allowed and in which positions they can be installed.
If too many circuits are added beyond the panel’s rating, it may be necessary to upgrade the panel instead.
Understanding the difference between tandem and standard breakers is important when planning electrical upgrades:
While tandem breakers increase circuit capacity, they do not increase the total electrical load capacity of the panel.
Tandem breakers are sometimes confused with double-pole breakers, but they serve different purposes:
Using the correct type of breaker is critical for proper electrical system function.
If you find yourself needing multiple tandem breakers to add circuits, it may be a sign that your panel is undersized for your electrical needs. In these cases, upgrading to a larger panel may be the safer and more reliable solution.
Learn more about upgrade costs in our guide to circuit breaker panel upgrade cost.
Selecting the correct breaker for your panel ensures safe and reliable operation. Breakers must be compatible with your panel brand and rated for the correct electrical load.
For more guidance, visit our How to Choose the Right Circuit Breaker guide.
For additional information on breaker types, troubleshooting, and electrical safety, visit our Circuit Breaker Resource Hub.
Knowing when and how to perform a circuit breaker replacement is important for maintaining a safe and reliable electrical system. Whether you are replacing a faulty breaker, upgrading an older electrical panel, or installing new equipment, choosing the correct replacement breaker helps protect wiring, appliances, and electrical devices from overloads and short circuits.
This guide explains common signs of breaker failure, how to identify the correct replacement, and important factors to consider before installing a new circuit breaker.
When Should a Circuit Breaker Be Replaced?Circuit breakers are designed to last for many years, but they can eventually wear out or become damaged. A breaker that no longer functions properly may fail to trip during an overload, creating a serious safety hazard.
Common signs that indicate a breaker may need replacement include frequent tripping, burning odors near the panel, visible damage, overheating, or a breaker that will not reset.
If you are experiencing these issues, read our guide on Signs of a Bad Circuit Breaker.
Before replacing a breaker, it is important to determine whether the breaker itself is defective or if another electrical issue is causing the problem.
Overloaded circuits, short circuits, damaged wiring, and faulty appliances can all cause breakers to trip. Simply replacing the breaker without correcting the underlying issue may not solve the problem.
Not all circuit breakers are interchangeable. Replacement breakers must be compatible with the specific electrical panel in which they are installed.
Major panel and breaker manufacturers include Siemens, Square D, Eaton, Cutler Hammer, General Electric (GE), Federal Pacific (FPE), Challenger, Pushmatic, and Zinsco. Always verify compatibility before purchasing a replacement breaker.
For additional guidance, visit our How to Choose the Right Circuit Breaker resource.
Replacement breakers must have the proper amperage rating for the circuit they protect. Installing an oversized breaker can allow wiring to overheat, while an undersized breaker may trip unnecessarily.
Common residential breaker sizes include:
The replacement breaker should match both the circuit requirements and conductor size.
Many property owners replace circuit breakers for one of the following reasons:
Older Federal Pacific (FPE), Challenger, and Zinsco breakers are commonly replaced during electrical upgrades due to safety concerns and limited availability.
Learn more in our guide on Replacing FPE, Zinsco, and Challenger Breakers.
In some situations, replacing a single breaker may not be enough. Older panels that are overloaded or lack capacity for modern electrical demands may benefit from a complete panel upgrade.
If your panel is full, you may also be considering options such as Tandem Circuit Breakers or adding additional circuits.
Learn more about upgrade considerations in our guide on When to Upgrade Your Electrical Panel.
The cost of replacing a circuit breaker depends on several factors, including breaker type, amperage, panel manufacturer, and labor requirements. Specialty and obsolete breakers may cost more than standard residential breakers.
If a larger electrical upgrade is needed, review our resource on Circuit Breaker Panel Upgrade Cost.
Electrical Supplies Unlimited carries a large inventory of new, used, surplus, and obsolete circuit breakers for residential, commercial, and industrial applications. We stock breakers from many leading manufacturers and can help locate hard-to-find replacement breakers for older electrical systems.
Whether you need a standard residential breaker or a specialty industrial breaker, our experienced staff can help identify the correct replacement.
If your circuit breaker is not resetting, it is usually a sign of an underlying electrical problem that needs attention. A breaker that immediately trips again, feels loose, or refuses to stay in the ON position may indicate an overloaded circuit, short circuit, ground fault, or a defective breaker.
Understanding why a circuit breaker will not reset can help you identify potential safety hazards and determine whether you need a simple repair, breaker replacement, or a larger electrical upgrade.
Why Is My Circuit Breaker Not Resetting?Circuit breakers are designed to shut off power when they detect dangerous conditions such as overloads or short circuits. If the underlying issue still exists, the breaker may refuse to reset in order to protect your electrical system.
In some cases, the breaker itself may be worn out or damaged and require replacement.
Many people do not realize that a tripped breaker must first be switched completely to the OFF position before it can be reset.
To properly reset a breaker:
If the breaker immediately trips again, further troubleshooting is required.
One of the most common causes of a breaker that will not reset is an overloaded circuit. Too many devices operating on the same circuit can exceed the breaker's rated capacity.
Try unplugging appliances, electronics, and equipment connected to the affected circuit before attempting to reset the breaker again.
If overloading is a recurring problem, you may need additional circuits or an electrical panel upgrade.
A short circuit occurs when electrical current follows an unintended path with little resistance. Short circuits can generate significant heat and may cause the breaker to trip instantly.
Signs of a possible short circuit include:
Short circuits should be investigated immediately to prevent potential fire hazards.
Ground faults are especially common in kitchens, bathrooms, garages, outdoor circuits, and areas exposed to moisture. Ground fault conditions can cause both standard breakers and GFCI circuit breakers to trip.
If moisture or damaged wiring is present, the breaker may continue tripping until the fault is corrected.
Like any electrical component, circuit breakers can wear out over time. Older breakers may become weak, fail internally, or lose their ability to properly reset.
Common signs of a bad breaker include:
Learn more in our guide on Signs of a Bad Circuit Breaker.
If troubleshooting confirms that the breaker itself is defective, replacement is often the safest solution. Modern breakers provide improved reliability and protection compared to aging or obsolete models.
Read our complete Circuit Breaker Replacement Guide to learn more about selecting the correct replacement breaker.
Some older electrical panels may have recurring breaker problems because the panel itself is outdated or operating beyond its intended capacity.
Common older breaker systems include Federal Pacific (FPE), Zinsco, Challenger, and Pushmatic panels. These systems are frequently upgraded due to safety concerns and replacement part availability.
Learn more in our guide on Replacing FPE, Zinsco, and Challenger Breakers.
If your breakers trip frequently, your panel is full, or your electrical needs have increased significantly, it may be time for a panel upgrade.
Modern homes often require additional capacity for HVAC systems, electric vehicle chargers, home offices, and other high-demand electrical equipment.
Learn more in our guide on When to Upgrade Your Electrical Panel.
Electrical Supplies Unlimited carries a large inventory of new, used, surplus, and obsolete circuit breakers for residential, commercial, and industrial applications. We stock products from many major manufacturers and can help locate difficult-to-find replacement breakers.
Whether you need a standard residential breaker, specialty commercial breaker, or replacement for an older electrical panel, our experienced staff can help you find the right solution.