The box contains a device that allows your local electric utility to remotely turn off either your water heater or heating/air-conditioning system, or both, during periods when the load on their sytem begins to reach its maximum capacity. This avoids a “brown out,” which is when the voltage throughout the electric utility’s service area drops below an acceptable level because of heavy electrical usage. Lights dim and some appliances will slow down or stop working, and some types of motors can be damaged by a brown out, but it avoids a “black out” total loss of electric service. This typically has happened in Florida during extremely hot summer days.

    The idea behind this system is “load shedding”: decreasing the electrical loads temporarily in rotating service areas during a period of high demand instead of stressing out the system. In exchange for allowing the electric company to turn off the power to your major appliances for a few minutes, you usually get a small reduction in the rate you pay for electricity. If you are not familiar with is setup, probably it was installed for a previous owner of the home. 

    The box will typically have a row of colored lights in a small window to indicate whether or not the electric utility has turned off the power, and which appliances are turned off. Here’s a diagram of one manufactured by ABB, a Swiss technology corporation.

    Also, some of these systems are no longer functional and abandoned in place. The one shown at the top of the page has long ago been disconnected from the house electrical system, but others around Florida are still hooked up—with the row of indicator lights on.

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Here’s links to a collection of our other blog posts about ELECTRIC PANELS:

• What causes copper wires to turn green or black in an electric panel?  

• What is the maximum number of circuit breakers allowed in an electric panel?

• When should a corroded or damaged electric panel cabinet or disconnect box be replaced? 

• What is a tandem circuit breaker? 

• When did arc fault circuit interrupter (AFCI) breakers first become required?

• Can an electric panel be located in a closet? 

• Can an electric panel be located in a bathroom? 

• Can you add circuit breakers by different manufacturers to an electric panel if they fit?

• My circuit breaker won't reset. What's wrong?  

• What is a split bus electric panel?

• How do I identify a combination AFCI (CAFCI) circuit breaker? 

• What does a circuit breaker with a yellow or white test button indicate? 

• What is the maximum gap allowed between the front of a recessed electric panel box and the wall surface surrounding it? 

• What are the requirements for NM-cables entering an electric panel box?

• Why is a fuse box/panel an insurance problem for homebuyers? 

• Why is bundled wiring in an electric panel a defect?

• What is the difference between GFCI and AFCI circuit breakers? 

• Why are old electrical components not always "grandfathered" as acceptable by home inspectors?

• What happens when you press the "TEST" button on a circuit breaker in an electric panel?

• What is a Dual Function Circuit Interrupter (DFCI)? 

• What is the difference between a Combination Arc Fault Circuit Interrupter (CAFCI) and an Arc Fault Circuit Interrupter (AFCI) circuit breaker?  

• What is the difference between "grounded" and "grounding" electrical conductors? 

• What does it mean when a wire is "overstripped" at a circuit breaker?

• Why is an old fuse panel dangerous?  

• Who is the manufacturer of those "bad" electric panels?

• Why is the circuit breaker stuck in the middle? 

• What is a double tap at a circuit breaker?

• What is the right electric wire size for a circuit breaker in an electric panel?

• What is the life expectancy of a circuit breaker? 

• My circuit breaker won't reset. What's wrong? 

• Why do some breakers in my electric panel have a "TEST" button on them?

• What is the right size electric panel for a house? 

• What do I need to know about buying a whole house surge protector? 

• What is the maximum allowed height of a circuit breaker (OCPD) above the floor?

• What is the maximum height you can mount an electric panel above the floor? 

• What is the code required clearance in front of an electric panel?

   Visit our ELECTRIC PANELS page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.