Is My Electrical Capacity Enough to Power My Home?

The electrical capacity is the total amount of electricity that your main electrical service can provide. The main electrical service is a panel that receives electricity via your utility company and supplies that electricity to all the circuits in your home. On the other hand, the electrical load calculates how much electricity is needed to run all your electrical appliances. It is measured in amperes or amps, a unit of electrical current that refers to the volume of electricity that flows via the wires.

Why Is It Important to Calculate the Electrical Load?

It’s important to calculate the electrical load as it tells you whether or not you can safely run all of your appliances, devices, fixtures, etc. As a rule of thumb, the load should not be more than 80 percent of the electrical capacity as this can cause an overload, and conversely, an electrical fire.

Is Your Electrical Capacity Sufficient?

So, how do you know if your current electrical capacity can handle the electrical load? Since no two homes are the same, you’ll need to do some math. Here’s how to calculate how many amps your home can handle:

How to Determine the Electrical Capacity

Your main circuit breaker will most likely contain the home’s total electrical capacity. However, if it doesn’t, you can follow the formula of Volts x Amps = Watts to calculate the electrical capacity of individual circuits. For instance, a 120-volt, 15-amp circuit can handle 1,800 watts (120 volts x 15 amps). But since the load shouldn’t be more than 80 percent of the capacity, the circuit should only bear 1,440 watts. All of the appliances plugged into a particular circuit should not go over 1,440 watts, to prevent an overload.

You can use the same calculation to determine your home’s total electrical capacity. Most homes have an electrical service of 100 amps at 240 volts, so that puts the capacity at 24,000 (100 amps x 240 volts). This means that all your appliances, fixtures, etc. shouldn’t exceed 24,000 at a time.

How to Calculate the Electrical Load

Once you’ve calculated the capacity, you can then compare it to the electrical load. This can be done by summing up the wattage ratings of all appliances, plug-ins, etc. that will be using electricity simultaneously. Here’s how to do it:

• Add the wattage ratings of all lighting and plug-in circuits.
• Add the wattage ratings of all permanent appliances, such as refrigerators, dishwashers, washer-dryers, etc.
• Subtract 10,000 watts from the total.
• Multiply it by 0.04 or 40 percent.
• Add 10,000 watts to the total.
• Add the wattage of either the air conditioning unit or the heating unit. (You won’t use them at the same time, so choose whichever has a greater rating).
• Divide the total by the number of volts your home uses (typically 240) to determine the electrical load.

Again, the electrical load should be 80 percent of the electrical capacity. If it exceeds that number, you’ll need to add more circuits to sufficiently (and safely) run all of your electrical appliances. But before you do that, make sure your breaker panel can actually handle the increase in load. Remember, you shouldn’t touch any of your electrical breakers, panels, circuits, etc. You should let a professional, like Beeson Mechanical Service, Inc., take care of that for you.

Don’t Want to Do the Math? Call the Pros

Calculating the capacity and load can be confusing, plus they can put your property at risk if you don’t do it right. To be safe, it’s best to consult a certified electrician, like Beeson Mechanical Service, Inc., at 317-535-9338, who can accurately find out how much electricity your home can handle. They can also help you install circuits to your electrical system should you decide to do so.