IS YOUR ELECTRICAL PANEL UNDERSIZED?

5 min readSep 24, 2019

The size of your electrical panel is the indicator of how many electrical units or appliances you can run in your home at one time. While some homes run on a combination of electricity and gas, allowing them to function with a smaller panel, other homes are fully electric and require much larger panels.

Determining the proper size of an electrical panel for your home is also dependent on how many and what type of appliances you have. Some appliances like computers, sound systems, and televisions require much less electricity than other larger appliances like washers and dryers, air conditioning units, and heating systems.

Determining the Appropriate Size Electrical Panel

Believe it or not, you don’t have to be an electrician to figure out the proper size for your home electrical panel. Choosing the right size for your homes electrical needs can be calculated with a simple equation.

Wattage Needs for Home

Take the square footage or your home and multiply it by 3. Let’s say your home is 1,750 square feet. Multiply 1,750 by 3 to get 5,250. This number is your homes wattage needs.

Wattage Needs for Kitchen

Next, you’ll need to determine the exact wattage needs for your kitchen. You will need a small appliance, 20-amp single-pole circuit for your kitchen and to find the amount of wattage needed, you can multiply 20 amps by the 120 volts it will be operating on, equaling 2,400 watts. Now add the 2,400 watts to the 5,250 watts you’ll need for your home.
5,250 watts + 2,400 watts = 7,650 watts

Wattage Needs for Kitchen Circuits

For your kitchen circuits, you’ll need to calculate in the electric range (at a 50-amp double-pole dedicated breaker, 50 amps times 220 volts) and the dishwasher, if applicable (at 20 amps times 120 volts). This will give you 11,000 watts and 2,400 watts to add to your total. 7,650 watts + 11,000 watts + 2,400 watts = 21,050 watts

Wattage Needs for Laundry Room Circuits

Your washer and dryer are important appliances to account for when determining the correct electrical panel size. Your washer requires a 20-amp single-pole dedicated breaker (20 amps times 120 volts) and your dryer requires a 30-amp double-pole dedicated breaker (30 amps times 220 volts). Now add 2,400 and 6,600 to your total.
21,050 watts + 2,400 watts + 6,600 watts = 30,050 watts

Total Wattage Needs Before AC & Heat

As per the National Electrical Code, you must calculate your homes wattage needs before adding in your central air conditioning unit and heating unit. The first 10,000 watts of your homes total needs are calculated at 100 percent and the remaining balance, which in this case is 20,050, is to be calculated at 40 percent. This coincides with the NEC.
20,050 x .40 = 8,020 watts
8,020 watts + 10,000 watts = 18,020 watts

Wattage Needs for Central Air & Heating

Now you can calculate the wattage needs of your air conditioning and heating unit. These units will run on a 60-amp double-pole dedicated breaker which can be calculated by multiplying 60 amps by 220 volts for a total wattage usage of 13,200 watts. Add this to your new total.
18,020 watts + 13,200 watts = 31,220 watts

Determining Your Total Amperage

In compliance with the NEC, divide your total wattage of 31,220 watts by 230 to calculate your total amperage. In this example, the total amperage for your home’s needs would be 135.73913. Electrical panels for a private residence are available in sizes of 100 amps, 125 amps, 150 amps, and 200 amps. Since we landed on amperage of 135.7 amps, we must round up to the next highest panel of 150 amps to suffice your homes wattage needs.

Now that you know exactly how to calculate the proper size electrical panel for your home, it’s also important to understand the signs that your current panel may be too small.

Your electrical panel is responsible for delivering electricity to numerous parts of your home in order for you to live safely and comfortably. Living with an overloaded panel can be dangerous and cause quite the headache. Pay attention to these possible signs.

Overuse of Extension Cords

Of course, it’s common to use extension cords in any home but too many can actually cause a major safety hazard. Extension cords were not created for permanent use within the home and can get in the way and even lead to damaged outlets.

If you find that you have extension cords plugged into many of your home’s outlets, it’s probably time to upgrade your electrical panel to a larger size in addition to installing more outlets.

You Live in an Older Home

Most older homes were constructed with a generic 60-amp electrical panel that could provide all of the home’s electricity, but as times have changed, so have homes and their electrical needs. Today, a 60-amp electrical panel will struggle or fail to get the job done and you will have to upgrade to one of the options previously listed. The lowest electrical panel offered today is a 100-amp and the highest is a 200-amp. Calculate your homes wattage needs to determine exactly what size your home requires.

Your Current Panel Is Nearing Its End

It’s not hard to figure out if your current electrical panel is nearing the end of its lifespan. Look out for a few common and obvious signs such as your lights flickering, appliances that aren’t performing to their full potential, using multiple appliances in your home will trip the breakers, or the panel has begun to simply malfunction.

Having an old or undersized electrical panel in your home can not only cause quite the inconvenience but it can also become incredibly dangerous. It’s important to know the signs to look out for when your panel has become insufficient for your home’s wattage needs. If you need help determining the proper size electrical panel for your home or have any further questions, do not hesitate to contact one of our experienced electricians.