Your electrical panel is the heart of your home’s electrical system.
It distributes electricity to the branch circuits that supply your house’s outlets and appliances.
Modern breaker panels have hot busbars with individual breakers that cut off power to circuits when the current exceeds their rating. Older homes use fuses instead of breakers.
Circuit Breakers
The circuit breakers in your electrical panel act like open gates, letting electricity flow to where it is needed. When a circuit gets overloaded with too many energy-demanding appliances plugged in at once or a sudden surge of electricity called a fault, the breaker detects this and shuts off the flow of power.
The National Electrical Code requires a standard breaker for each circuit in your home, except the main breaker which controls the whole house. However, the NEC also allows AFCI (arc fault circuit interrupters) to replace standard breakers and is mandatory for bedrooms in newer homes.
A single-pole breaker takes up one slot in your electrical panel and typically protects 15- or 20-amp circuits. They are the most common breaker in your home. If you notice a burning smell, you may have a faulty or overheated breaker. It can be very dangerous and should be replaced right away. If you touch your breaker and it feels hot, that is another sign of a faulty breaker.
Wires
The wires in your breaker box are either bare copper or covered with plastic or rubber-like polymers. These are designed to prevent current leakage and reduce the risk of electrical fires.
BLACK (OR RED) = HOT – carries current from the panel to switches, receptacles and appliances. It is typically the top layer of wires in the breaker panel and is also the most likely to be energized when the switch is turned on.
PRO TIP: It is customary to install ground wires first, then neutrals. This makes it easier to add a circuit later, because the new wires will terminate to the ground bus bar rather than directly to a breaker slot.
The bare copper grounding wire connects to the main service ground rod outside and allows fault current to return through this path instead of arcing inside the breaker box. It also provides a means to check that the grounding rod is in good condition.
Wiring Diagrams
A wiring diagram is a kind of schematic that shows the interconnections between components in an electrical circuit. The wires in a wiring diagram are usually color coded to identify which type of wire is which. The most common colors are black and white. The white or neutral wire carries power from the service panel to the light switches and outlets in your home. Black wire, on the other hand, indicates that the switch is being used.
The wires also carry power from the switch to a two-pole circuit breaker that then powers a transformer. After that, the power flows back to another two-pole breaker and then on to a single pole breaker.
Whether you’re installing a new light switch or replacing a dead outlet, understanding how your electrical panel works will help you get the job done properly. To get started, make sure that you have access to one of the best online tools for drawing wiring diagrams.
Safety
An electrical panel is a main control unit responsible for distributing electricity throughout the home or building. It contains circuit breakers or fuses that keep all outlets and light fixtures working. In case of a power surge, the circuit breakers help protect the wiring and appliances from electrical damage by shutting off power quickly.
It’s important for homeowners to know where their breaker box is so they can shut off power when necessary. It’s also helpful for them to understand how their breaker box works so they can fix problems like blown fuses and tripped circuits themselves.
Before inspecting electrical panels, it is important for inspectors to follow proper safety procedures. This includes wearing the appropriate PPE, such as gloves and eye protection. It is recommended to always keep a distance of at least three feet from any equipment that may be energized. Also, always maintain clear sightlines to prevent accidental contact with live electrical equipment.
