How to Replace an Electrical Breaker Panel

new breaker panel
  • 25 hours
  • Advanced
  • 5,000
What You'll Need
A large electrical entrance panel
GFCI circuit breakers
AFCI circuit breakers
Wire cutters
Wire stripper
Screwdriver bits
Junction boxes
Replacement cables
Wire nuts of different sizes

For decades, innovative technologies have been swarming the markets, bringing us all kinds of new and improved electrical appliances, equipment, and gizmos that have added to the power requirements of our electrical entrance circuit breaker panels.

Caution: Upgrading an electrical breaker panel is an advanced electrical project. It would be extremely dangerous to attempt this if you didn't have the necessary expertise, and in some places, it's illegal to make these kinds of changes without a professional license. If you're interested in this process, we outline it below, but please note that we do not recommend undertaking it without an expert.

In the 1960s, a 60 Amp panel, often filled with a bunch of fuses (Figures 1a and 1b), was adequate to supply electrical power to a full house—a few light fixtures and outlets, an electric stove, a fridge, water heater, water pumps, etc.

circuit breaker with glass fuses

The 1970s and 1980s saw the appearance of electric baseboard heaters, electric furnaces, central air conditioning units, heat pumps, and many more machines. All this new functionality has driven the need to upgrade from 60 Amp and 100 Amp electric panels, and even to 200 Amps and more.

Compare circuit breaker supplies on Amazon.

The innovation has only accelerated in the last few decades, bringing us automated HVAC units, spa-style tubs, heat pumps for pools, large entertainment systems, and increasingly popular electric cars, which require fast, powerful chargers right at home.

So it’s only fair to assume that many older, or even not-so-old houses require some kind of upgrades in their power distribution system to meet ever-increasing electrical needs. This might mean upgrading from an old electrical panel with the disposable fuses (Figure 1), or it might require moving from an early breaker panel with only 24 circuits or less.

Special Note #1: To save time and avoid being without power for an extended period, you can install the new panel on the wall next to the old one and then proceed with the preliminary wiring of the new and some of the existing circuits into the new panel (steps 4.2 to 5.5). This will make it possible to eventually install the new larger mast and associated connections in the same place as the initial entrance, making it inconspicuous.

Upgrading is not cheap, though. Nor is it easy. If you're going to try it, you need to be careful and organized. Realistically, as we note above, this is probably a job for a certified professional, but you're still the one hiring them, so you may want to know what you're getting into.

Step 1 - Figure Out How Much Power You Need

All the new luxuries you plan on acquiring in the future will undoubtedly create a greater current demand and require more breaker slots in your electrical entrance. Although electrical appliances are becoming increasingly energy-efficient, some types of equipment such as HVAC (Figures 2a & 2b) are quickly becoming popular, since they combine heating, cooling, and air exchanging inside older. They also often require the installation of multiple units, which will drive up the burden on your system.

two types of air conditioner

Scientific developments also bring new technologies, such as increasingly popular electric vehicles (EVs), which require fast home-based charging stations for daily use, and may require your panel to handle higher current than it used to. EV charger stations (Figure 3a & 3b) are electric boxes that act as gates, sensing when they're connected to a car and closing a relay that allows the electricity to flow in for charging.

car charging cables

Many families own two vehicles, so new and upgraded homes will likely require two stations. A 32 Amps Level 2 station makes a good choice for a starter station—typically charging a car at 7.2kWh. The 40 Amp Level 2 stations can charge faster, but they require 50 Amp breakers and heavier gauged wiring, which adds considerably to their cost.

The National Electrical Code requires circuits to be rated at 25% more amperage than a charger's output. For example, if you want a 40 Amp charger, you'll need to wire it to a 50 Amp circuit.

Step 2 - Choosing the Right Panel

Make a list of your major appliances, with the breaker number assigned to each one, along with their power rating and the time of day they're mostly in use. Add to this list all any equipment you plan on acquiring later.

This should provide a better picture of what your major power consumptions are, and when your system works the hardest. Knowing the total amount of kWh will help you balance the load within the panel. The totals will also give you an idea of what size electric panel you need. Finally, it will help determine what goes on your individual circuits, how many breakers you'll need, and what spare slots you'll have left.

At this final stage of the planning, it's advisable to consult a reliable certified electrician to get professional input on your plan.

Step 3 - Upgrading the Breakers

There are three types of breakers available for residential breaker panels—standard, GFCI, and AFCI. The standard breaker (Figure 4a), though still widely used, may not protect your household equipment as much as you'd like. The more efficient electronically operated breakers, GFCI and AFCI, can detect the smallest alterations in current within a circuit, offering better responsiveness in bad electrical situations.

GFCIs (Figure 4b) address shock hazards and are most often found where electrical circuits may accidentally come into contact with water, including in kitchens, bath and laundry rooms, exterior surfaces, and outbuildings.

AFCIs (Figure 4c) are designed to detect “arc faults” caused by damaged wires inside walls, improperly installed switches and outlets, or current leak to the ground. They can shut these problems down before they heat up too far, thus preventing fire hazards.

circuit breaker fuses

Special Note #2 - If you're planning the replacement of a breaker panel with 20 or 24 breakers, it may be worth upgrading with a larger panel of the same brand name, as each manufacturer has its own very specific fitting system to secure the breakers in place, and they tend to be incompatible with each other.

Step 4 - Planning the Project

As you probably realize by now, a project of this nature is a significant investment, which is more reason to do it carefully to prevent serious shortcomings along the way. Knowing that the entrance panel meets contemporary standards will make a house much more appealing to potential future buyers, though. It's probably a good idea to start a file with documents related to your upgrades, in case the work you put into the building becomes relevant in a future financial transaction.

4.1—Before anything else, make sure to obtain a permit from your municipality and/or from your electrical service provider, since they own the equipment right up to the entrance panel, and they will be doing the ultimate switch-over (Figure 5).

building permit

4.2—Divide your list from step 2 into three priority lists and label each as phase 1, phase 2, and phase 3 as listed below—the preliminary and all other wirings should be done following that order.

Phase 1—The 120-V circuits you can't do without (eg. TV, phone, internet, important lights and outlets, etc.)

Phase 2—The 240-V circuits you must maintain (eg. hot water, range, etc.)

Phase 3—All other circuits (eg. washer, dishwasher, clothes dryer, other lights and outlets, etc.)

Step 5 - Installing the Panel

5.1—Fasten the new panel solidly into place as specified in “Special Note #1”.

5.2—Switch off the main breaker on the old panel (Figures 6 & 7), then remove its cover, exposing all of its wires and breaker terminals.

circuit breaker panel

5.3—Disconnect the wires from each breaker as planned per each phase.

5.4—Remove the selected breakers and their now disconnected cables from the old panel box.

5.5—Reinstall the old or new breakers to service those same cables into their proper slot inside the new panel box and reinsert the cables into the new panel (providing they're long enough), reconnecting each one to its intended breaker wire terminal—either the same or a replacement breaker—switching them off as you proceed. The 120-V circuit distribution should be kept as balanced as possible between the two bus bars.

Step 6 - Cables Too Short

Often while doing such a transfer, some of the cables on the opposite side of the panel end up being too short, in which case you should proceed as follows:

6.1—In a neatly organized manner, install a terminal box on the wall for each of the short cables, making sure each one is properly identified.

6.2—Add extension cables of the same size long enough to cover the gap between the junction box and the electric panel, doing the necessary splicing inside those junction boxes (Figure 8).

electrical junction boxes

6.3—The other end of the extensions can then be inserted inside the panel through a cable connector and connected to the proper breaker wire terminals, neutral bus, and ground bus bars.

6.4—Repeat the exact same procedure from steps 5.3 to 5.5—or down to 6.3 if necessary—for all subsequent circuits.

Step 7 - Removing the Old Panel and Accessories

After all the stages are completed, and all the wiring is removed from the old panel, the pre-scheduled electric utility company has to cut the power off from the grid so that the electrical contractor can shift the feed to the new panel. You can then proceed to remove the panel from the wall along with all the conduits used right up to the top of the electrical mast. Reinstalling a new mast will probably have to be done by your certified electrician, as that side of the electric panel belongs to the utility company.

Step 8 - Circuits Back On

Once you check your work on the connections between the panel and the grid, your electrical contractor can reactivate your panel. This is done by switching on the main breaker first, with all the circuit breakers still OFF, then switching them on one at a time to prevent a power surge into your system.

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