Low voltage circuit breakers are used to protect electrical systems operating at voltages typically below 1,000 volts. These breakers are commonly installed in residential homes, commercial buildings, and light industrial facilities to protect electrical circuits from overloads, short circuits, and other electrical faults.
Because low voltage systems power most everyday electrical devices and appliances, choosing the correct breaker is essential for maintaining electrical safety and reliability.
What Is a Low Voltage Circuit Breaker?A low voltage circuit breaker is designed to automatically disconnect electrical power when current exceeds safe operating levels. These breakers protect wiring, appliances, and electrical equipment from overheating or damage caused by electrical faults.
Low voltage breakers are commonly found in:
Thermal magnetic breakers are the most common type used in residential electrical panels. They use heat and magnetic force to detect overloads and short circuits.
GFCI breakers are designed to detect ground faults and quickly shut off power to prevent electric shock. They are typically required in areas where water may be present, such as kitchens, bathrooms, garages, and outdoor outlets.
AFCI breakers detect dangerous electrical arcs caused by damaged wires or loose connections. These breakers help prevent electrical fires and are now required in many residential circuits by modern electrical codes.
Low voltage breakers protect electrical systems in many environments, including:
These breakers are designed to safely interrupt electrical current while maintaining reliable operation for everyday electrical loads.
When selecting a low voltage breaker, it is important to consider the following factors:
Using the correct breaker ensures proper protection and prevents damage to the electrical system.
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.
Below is our growing library of circuit breaker guides designed to help homeowners, electricians, and contractors understand electrical safety, breaker selection, and troubleshooting.
Visit our Circuit Breaker Resource Hub to explore more information about breaker types, electrical safety, and selecting the right circuit protection for your project.
ESU buys and sells new & used Circuit Breakers, Fuses, Switches, Plugs and more for Lakeside in San Diego.Electrical Supplies Unlimited buys and sells new & used Circuit Breakers in Lakeside and surrounding areas including Alpine, Jamul, Santee, El Cajon, La Mesa, Spring Valley 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 and other electrical supplies.
ESU Inc has been in the electrical supply business for over 40 years. We have a large inventory of new, surplus and recycled electrical supplies both for the commercial and residential markets. We are a fully stocked Electrical Distributor and Electrical Wholesaler with many different lines in stock. We specialize in hard to find items. Our staff is very knowledgeable and our mission is to ensure that our customers expectations are exceeded. Ask around, our reputation is what makes us! Or just call to find out yourself at 858.558.2850.
We stock most major brands including 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, Ed, 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 buys and sells new and used Circuit Breakers and more for Lakeside in San Diego and surrounding areas including Jamul, Santee, El Cajon, La Mesa, Spring Valley and many more. Of course, we can arrange shipment on a wide variety of products to service those outside our area. We will also purchase your used Transformers.
We purchase most major brands including Acme, Westinghouse, Cutler Hammer, ITE Siemens, FPE Federal Pacific, Square D, General Electric and Zinsco products. We are a fully stocked Electrical Distributor and Electrical Wholesaler with many different lines in stock.
Circuit Breakers Electrical Supplies Unlimited is your go-to source for Circuit Breaker electrical supplies in Lakeside and surrounding areas. We have a large inventory of most brands of circuit breakers including most amperages and voltages. We carry a large variety of manufacturers, including Zinsco, Federal Pacific FPE, Pushmatic, Bulldog, Cutler, Hammer, ITE Siemens, Square D etc. in our San Diego store. We carry most amperages and voltages. Some examples of what we carry:
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!
If your circuit breaker keeps tripping, it usually means your electrical system is protecting itself from a potential hazard. Circuit breakers are designed to shut off power when they detect overloads, short circuits, or electrical faults. While occasional trips can be normal, a breaker that trips frequently may indicate a deeper electrical problem that needs attention.
This guide explains the most common reasons why a circuit breaker keeps tripping and what homeowners can do to troubleshoot the issue safely.
What Does It Mean When a Circuit Breaker Trips?A circuit breaker trips when it detects electrical current exceeding safe limits. When this happens, the breaker automatically shuts off power to prevent overheating, electrical fires, or damage to appliances and wiring.
If your breaker repeatedly shuts off power, it's important to identify the cause rather than simply resetting the breaker each time.
The most common reason a breaker trips is an overloaded circuit. This occurs when too many appliances or devices draw power from the same circuit at the same time.
High-wattage appliances such as space heaters, microwaves, hair dryers, and portable air conditioners can easily exceed the circuit's capacity.
To prevent overloads:
A short circuit occurs when a hot electrical wire touches a neutral wire or grounded metal component. This creates a sudden surge of electrical current that forces the breaker to trip immediately.
Short circuits may be caused by:
Because short circuits can create dangerous electrical conditions, they should be inspected by a qualified electrician.
Ground faults occur when electrical current flows outside the intended circuit path and contacts a grounded surface. This type of fault commonly happens in areas where water is present, such as kitchens, bathrooms, garages, and outdoor outlets.
Ground fault circuit interrupter (GFCI) breakers are designed to detect these conditions and shut off power quickly to prevent electric shock.
If a breaker trips when a specific appliance is turned on, that device may be malfunctioning. Appliances with damaged cords, worn internal components, or electrical faults can draw excessive current and cause breakers to trip.
Try unplugging the appliance and resetting the breaker. If the breaker stops tripping, the appliance may require repair or replacement.
Although circuit breakers are designed for long service life, they can eventually wear out. A breaker that trips repeatedly or fails to stay reset may be defective.
In older homes, the electrical panel itself may also be outdated and may not handle modern electrical loads effectively.
While homeowners can safely reset a breaker, recurring electrical problems should be evaluated by a licensed electrician. Electrical professionals can diagnose wiring issues, replace defective breakers, and determine whether your panel needs upgrading.
Addressing these problems early helps prevent damage to appliances and reduces the risk of electrical fires.
If a breaker needs replacement, it is important to select one that is compatible with your electrical panel. Breakers are designed to match specific panel brands and models to ensure proper fit and safe operation.
To learn more about selecting the correct breaker, visit our How to Choose the Right Circuit Breaker Guide.
For additional information about breaker types, electrical safety, and panel upgrades, explore our complete Circuit Breaker Resource Hub. Our guides help homeowners, electricians, and contractors understand how to maintain safe and reliable electrical systems.
For a complete overview of breaker types, brands, and electrical safety considerations, visit our Circuit Breaker Resource Hub where we provide expert guides for residential, commercial, and industrial electrical systems.
For a complete overview of breaker types, brands, and electrical applications, visit our Circuit Breaker Resource Hub.

Electrical Supplies Unlimited buys and sells new & used Circuit Breakers in Sunnyside 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 Sunnyside, 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 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:
Learn more in our guide on When to Upgrade Your Electrical Panel.
A new electrical panel offers several advantages beyond simply replacing aging equipment.
Modern electrical panels also provide greater flexibility for future expansion and additional circuits.
Today's residential electrical systems commonly utilize:
The proper panel size depends on the building's electrical load requirements and future expansion plans.
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:
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.
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.
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.
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.
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.