The Heart of Your Home’s Electrical System

Have you ever wondered how much the electrical system in your home has changed in the last 100 years or so? The electrical service panels have certainly changed, and here’s how.

Electrical service panels have come a long way in the past decade. Almost every home has some type of service panel, whether it be a fuse panel or a circuit breaker panel. Commonly, these service panels are located in utility rooms, garages or basements. Along with these service panels, it’s likely that you have a subpanel that controls other areas of your home, garage or outbuildings.

Before 1950, a 30-amp fuse panel was the norm. These fuse panels featured two plug fuses to protect the branch circuits and a knife-blade switch to disconnect power. The fuses were installed in a ceramic fuse holder, which was mounted within a black metal enclosure.

This 30-amp service panel supplied 120 volts to a home, unlike the 240 volts today’s service panels do. These panels are no longer sufficient in today’s age and must be updated to at least a 100-amp circuit breaker panel to satisfy both FHA and other lending institution requirements for home sales. Besides, you’ll be needing much more power in your home and definitely much more than this service panel can provide.

Between 1950 and 1965, a new age of service panels emerged. The 60-amp service panel became widely accepted and preferred. This panel was mounted inside a gray metal cabinet and featured a 240-volt feed. It had two cartridge fuse blocks and four plug fuse blocks.

The first cartridge fuse block was used as the main disconnect and held 60-amp fuses. The other was used as an appliance feed and held 30-amp fuse. It fed power to things like electric dryers, water heaters, ovens or electric ranges.

The four plug fuses allowed for four individual branch circuits. In smaller homes with little electrical needs, this was often sufficient to power the home. These panels did have their limitations also though, as they could not support more than one 240-volt feed or more than the four individual branch circuits. It did, however, offer a panel schedule index that was placed inside the door of the panel so that the circuits could be labeled as to where they fed within the home.

Finally in the 1960’s, the circuit breaker panel was invented and has become the standard ever since. It not only provides expandable circuit spaces, but also provides 240-volt, 100- and 200-amp services to homes. This panel features a main breaker and two rows of circuit breakers that are used for branch circuits. This panel allows you to supply power to outlets, lighting and subpanels in and around your home. Circuit breakers started a new age of resettable devices, unlike fuses that had to be changed when they blew.

Circuit breaker panels are the norm in housing today with 100- and 200-amp circuit breaker panels being the most common. In fact, 100-amp panels are the minimum allowed. Besides the main breaker rating, these panels have different amounts of circuit breaker spaces. One may have 12, while others may have 24 spaces. These panels have a neutral buss and often a ground buss. A panel schedule is offered to provide a way of knowing which breaker feeds what device or circuit throughout the home.

For peace of mind that the “heart” of your electrical infrastructure is safe—and not what some of these photos show can happen to a unsafe main circuit breaker panel—you can contact William J. Shea Electric at 631-668-1600 or or visit their website at www.williamjsheaelectric.com.