Your home's load center (also known as the breaker panel, service panel, breaker box, fuse box, or electrical panel) is the command
center of your home's electrical supply system. All electrical power for your home flows into the load center where it is then distributed
safely into multiple smaller branch circuits. It is in this panel that your entire home's circuit protection resides, and where power can be
disconnected from specific circuits, or if need be, the entire electrical system. There are several types of load centers available, and
choosing the right equipment may seem daunting, but don't worry. Menards® offers a wide selection of products from the best known
and most respected names in the business, and this buying guide will help you choose the right equipment for your home.
Before You Shop
Before you can begin to look for a new load center, there are a few things you need to consider. First,
you'll want to check with your electrical service provider and local electrical inspecting authority for
specific requirements. You will also need to determine the amperage capacity, or ampacity, of your
current load center, as well as the number of 1-pole and 2-pole circuits within. If you need to add
circuits, and room to grow, now is the time to address it. Finally, you'll need to determine the amperage
of your existing utility-provided electrical power, or service. If your electrical needs will be greater than
your current you may need to increase, or upgrade, your service.
Main Breakers vs. Main Lugs Panels
Every home has at least one very large switch that serves as the service disconnect. In other words, it
disconnects utility power from the house. A service disconnect must also provide over-current and
short-circuit protection. For residential use, a main breaker is the most common type of service
disconnect. In some cases, it is outdoors, combined with or located near the electrical service meter
enclosure. However, in most single-family residential homes, it's incorporated with the load center.
Thus, a main breaker load center has a factory-installed main breaker that serves as the service
disconnect and controls the power to all of the branch circuits within the enclosure. Switching this
breaker to the "off" position shuts off power to all circuits at the same time.
CAUTION: The wires feeding the main breaker are still live and potentially hazardous. Stay clear of
them!
A main lugs load center does not include a main breaker. It has only lugs, or terminals, for the wires that feed it. Main lugs load centers
are sometime called "sub" or "sub-feed" panels. They are sometimes installed adjacent to a main panel to provide additional circuits
when the main breaker panel is full, or they may be installed far away from the main panel to provide a local disconnection for circuits in
a detached building, garage or room addition.
Ampacity
All load centers are rated by ampacity. This is the maximum continuous current that your load center
has been designed to handle. It is critical to determine the necessary ampacity needed for your home
before proceeding further with selecting equipment. It is not as simple as adding up the ampere ratings
of the breakers in the panel. There are numerous resources available for calculating total electrical
power needs, or load. If you are unsure of your power needs, please contact your local electrical
inspecting authority for guidance, or seek a qualified electrical professional. For older homes, 100-amp
service is common while 200-amp service is common for newer homes. For very large homes and
homes with greater electrical needs, 400-amp service is common; however, service is typically routed
through two (or more) 200-amp load centers.
Spaces and Max Circuits
Circuit Breakers
Other Types of Breakers
Load centers are also rated in terms of
the number of standard-size 1-pole
breakers that the load center will
accommodate (1-pole means one 120volt branch circuit). Branch circuits are
those that provide power to everything
in your home: lights, outlets,
appliances and so on. Typical
residential circuits are 1-pole (120-volt)
for lights and outlets or 2-pole (240volt) for appliances such as an electric
range, dryer or water heater. Finally,
load centers are rated in terms of the
maximum number of circuits they will
accommodate. Some load centers are
designed for special breakers that are
two 1-pole breakers joined together,
but are the same size as a standard 1pole breaker, and occupy only one
space in the load center. Depending
on the brand, they are known as twin,
tandem or half-size breakers. Because
these breakers allow two circuits to fit
in the space of one full-size breaker, a
load center may have a maximum
circuit capacity greater than its number
of spaces. Check with your local
electrical inspector to determine if such
breakers are allowed for your
application.
A standard circuit breaker provides
three basic functions:
There are various types of electronic
breakers that provide levels of
protection standard breakers. These
breakers provide the same three
functions as a standard breaker, but
provide additional levels of protection
to people or wiring systems. An Arc
Fault Circuit Interrupter (AFCI)
mitigates the effect of arcing conditions
in the wiring system or connected
devices, which may include poor
terminations or cut wires. When
localized arcs occur, the AFCI deenergizes the circuit. Ground Fault
Circuit Interrupters (GFCI) provide
personnel protection by mitigating the
effects of electric shock. When the
breaker detects current leakage to
ground, the circuit is de-energized.
Dual function circuit breakers combine
all the functionality of standard, AFCI
and GFCI circuit breakers. Local
electrical codes will specify in which
locations of the home each type of
breaker is required.
1) Mitigates effects from overcurrent in
the wiring system which could lead to
melted insulation and fire hazards
2) Mitigates the effects of short circuits
3) Acts as a disconnect to de-energize
a circuit.
For most residential applications,
breakers are designed for single
phase, 120- or 120/240-volt
applications. A 120-volt breaker will be
a single-pole breaker, while the 240volt rated breakers will be a doublepole breaker, taking up 2 spaces in the
panel. Each breaker will have an
ampere rating, and it is important that
the wire size chosen is rated for the
breaker rating or greater. You cannot
use a breaker that has a higher
ampere rating than the installed wiring.
Tandem breakers (also known as
twins, 1/2" or space savers) are
standard breakers that are half the
size of the traditional breaker. You will
need to check the wiring diagram on
the panel to confirm that the particular
panel accepts tandem breakers.
Indoor vs. Outdoor Load Centers
Accessories
Load centers are listed for either indoor or outdoor use. Both
types are designed to prevent access to electrified
components, but outdoor-rated load centers are designed to
withstand direct exposure to weather. Choose an outdoor-rated
load center for installation in areas that are subject to rain and
snow.
Menards® also offers a variety of useful load center
accessories:
- Covers and Enclosures: replace damaged covers and
enclosures with one of our special orders from the
manufacturer
- Padlock Attachments: keep breakers in the ON/OFF position
and lock the load center door
- Ground Bars: sometimes required depending on the
application of the load center
- Filler Plates: fills the space if a circuit breaker is removed and
prohibits access to live parts
Check MENARDS.COM® for access to more accessories not
stocked in stores
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