How To Buy Electrical Panels
A breaker panel, also known as an electrical panel, load center, service panel or breaker box, is a steel box that holds multiple circuit breakers wired to circuits that distribute power throughout your home. This guide will teach you about the features of typical electrical panels, and what type of breaker is best for your home.
Tip: Before purchasing a breaker panel, check with local authorities and your utility company to be sure you select a panel that conforms to code requirements.
Circuit breakers turn the power to your home on and off to protect wiring from damage by “tripping” when an electrical short or overcurrent occurs.
There are two main reasons you may want to replace your electrical panel or add a sub-panel: if you need to add circuit breakers but have reached the capacity of your current breaker panel, or if you want to upgrade from fuses to circuit breakers.
A new breaker panel will not provide more power to your home. If your home needs more power overall, use the services of a professional electrician to upgrade, a process that will include a new breaker panel as well as other accessories, such as new cables and a new electrical meter.
Electricity comes into your home via wires that connect to your breaker panel, which typically consists of a main breaker, circuit breakers and bus bars.
- Main breaker: Large double pole circuit breaker that limits the amount of electricity coming in from outside to protect the circuits it feeds. It also identifies your breaker panel’s amperage capacity.
- Circuit breakers: Stacked in the panel and have an ON/OFF switch that controls the flow of power.
- Bus bars: Receive power from the two thick black wires that bring power in from the electrical meter, then carry power through the circuit breakers to the circuits.
- Neutral bus bars: Connect to the main circuit’s neutral wire. The neutral bar provides the contact point for the white wires that return electricity back to the breaker panel after flowing through the black wires to power a device. Depending on local codes and configurations, your home’s main grounding wire also connects to the neutral bar.
- Grounding bus bars: Unite all the grounding wires from the breaker panel’s various circuits and connect them to the ground bar. It is also connected to a grounding conductor that leads underground, the metal enclosure and, if it’s the main service panel, to the neutral bar; the ground bar is not connected to the neutral bar at sub-panels.
There are different types of breaker panels to choose from, each of which meets a certain code or application, depending on your local requirements.
Main breaker panels have a built-in main breaker that can be used to shut off all power to your residence. A main breaker is a large double-pole circuit breaker that limits the amount of electricity coming in from outside to protect the circuits it feeds. It also identifies your breaker panel’s amperage capacity. Main breakers can be installed when the meter and feeder cable are within 10 feet of the panel. Consult your local codes to see if your panel will meet this or another requirement for proper installation.
Main lug panels do not have a main breaker. Instead the line wires run to lugs. This type of breaker panel requires a separate disconnect. The main breaker, which would function as the disconnect, may be located at the meter, or if the main lug panel is used as a sub-panel, it may be connected to the breaker at the main panel. In the event of a fire, the separate disconnect at a meter can be helpful to fire authorities who don’t have to enter the building to cut power.
A sub-panel is also ideal for situations where multiple circuits are needed in a single separate area, like a workshop or greenhouse.
Be aware, however, that sub-panels do not increase the amount of available power. If an increase in electricity is needed, contact your local utility company or an electrician.
Sub-panels are typically powered by a circuit from within the main panel and do not have their own disconnect.
Tip: The amp rating of the circuit in the main breaker panel must be the same or smaller than the rating of the sub-panel connected to it. Also, the only limit for the number of sub-panels you can have is the number of available circuits in the main breaker panel.
Transfer switches are a type of sub-panel that transfers portable generator power into electrical power through your breaker panel.
If you live in an area where storms are common, you may have a permanent backup power generator that uses an alternative power source, like propane or natural gas.
The generator can be wired directly to the household breaker panel, providing a seamless switch from utility service to backup power when the electricity goes out.
Some generators come with a transfer switch that carries the same rating as the home’s main breaker panel.
There are two models of transfer switches:
- Automatic transfer switches require a larger initial investment but provide continuous protection for homeowners.
- Manual transfer switches are less expensive and require you to power up the generator and manually switch the load to the backup system.
Read our Transfer Switches Buying Guide to learn more about transfer switches.
Breaker panels are identified by the amount of amperage they provide and the number of circuits they accommodate.
- The amperage will be identified on your current panel’s main breaker.
- When replacing your panel, either match the amperage capacity of your current model, or upgrade if your power needs have grown.
- Amps typically range from 60 amps in older homes to as much as 200 in new construction.
- Make sure the wire as well as other devices on the circuit are rated for the proper amps for the install.
- One hundred amps is the minimum required by the National Electrical Code (NEC), but 150 is increasingly common.
- While 100-150 amps are generally suitable for most homes, breaker panels are also available in 200- and 400-amp units.
A circuit breaker is sized to operate at 80 percent of its rated capacity, so calculate how many you need based on how many amps you need covered.
Add up the loads of the devices and appliances that will run on the circuit. These are usually identified on a sticker or label attached to the items.
If the load is calculated in watts, use this formula: watts divided by volts = amps. Example: 1,400 watts divided by 120V = 12 amps.
Different types of circuit breakers include:
Single pole, or 1 pole, circuit breakers provide 120 volts in various amp ratings. Single pole circuit breakers rated 15 to 20 amps are typically used for receptacles and lighting. They are available in 3 types: Full size (1-in. wide), half size (1/2-in. wide) and twin/tandem (1-in. wide with 2 switches & controls 2 circuits).
Double pole, or 2 pole, circuit breakers provide 240 volts in various amp ratings. Double pole circuit breakers are typically used for appliances and hot water heaters.
Arc fault circuit interrupters (AFCI) are designed to shut down power to a circuit when they detect arcs of electricity caused by worn or damaged wires. AFCIs are used to protect circuits in bedrooms and common areas. Combination arc fault circuit interrupters (CAFCI) protect against against the same arcs covered by AFCI as well as low-energy series arcing. They are becoming more common in homes as they protect downstream branch circuit wiring and power cords.
Ground fault circuit interrupters (GFCI) break a circuit instantly when a short is detected. They are used to protect circuits in wet areas such as bathrooms, garages, unfinished basements and kitchens.
Tip: If you are upgrading your breaker panel to accommodate more 240V circuits for appliances that draw high current, like air conditioners and stoves, read our Circuit Breakers Buying Guide to learn more about these and other circuit breakers.