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Before loading a circuit with your holiday lights or kitchen appliances, you should know about your breakers. These devices help make sure that your home stays safe from electrical damage. Motorized electronics need dedicated circuits to operate safely, meaning one circuit serves one item at a time.

But, how do breakers and dedicated circuits help keep you safe? How many watts can a 15-amp breaker handle? Let’s look at what these terms mean and how much power you can draw from your home’s basic circuits. 

The Basics: What You Must Know About Your Electrical Circuitry

Here are some answers to the common questions out there about home circuits:

What’s a Circuit?

A circuit is a pathway for electrical current to travel on. These circuits consist of wires or other conductive materials that guide the electricity. This process is how electricity gets to your home. 

Once the electricity reaches your home, it gets a little more complex. Either a circuit breaker or fuse box divides the electricity into several circuit branches.

One of these circuits is the 15-amp circuit. These circuits are great for smaller appliances, consumer electronics, and lights. 

What Is Circuit or Electrical Load Capacity?

Close-up of an electrician working on a circuit breaker

Each circuit has a total amount of current that it can handle safely. The total amount of power drawn from the source without causing damage is the circuit capacity. 

Your house, as well as each breaker associated with the different areas, acts as a circuit. Your home is one circuit broken down into many smaller ones. To prevent overload, electricians will route power through a house to avoid excess power going to one appliance or breaker.  

What Is Circuit Overload?

If the capacity for a circuit is less than the total power being drawn, then that circuit overloads. A circuit overload is a dangerous thing to have because of the damage it can cause. 

Electrical fires, heat degradation, and other damage can happen due to overloaded circuits. These risks are why it’s important to know how much power a circuit can handle. 

Calculating the Circuit Load Demand

Close-up of a white circuit breaker with black switches

To calculate the circuit load capacity for a 15 amp circuit, we need to understand a few things. 

First, there is the concept of Ohm’s Law. This law from physics tells us that the current of a circuit is related to the resistance and the voltage. Resistance is the difficulty the current experiences in moving. Voltage is the potential of the electrical current to move. 

We also need to know that amps relate to the wattage and voltage of a circuit. The wattage of a circuit is the electrical power drawn from the circuit. 

Finally, we should understand the idea of continuous load or a constant draw of power from the circuit. The NEC recommends that a circuit under continuous load uses no more than 80% of its capacity. 

So, our calculation looks like this for the wattage that a 15 amp breaker can handle:

15-amps * 120 volts * 0.8 = 1,440 Watts

So, we can draw up to 1,440 Watts from a circuit safely. Though, that assumes the standard home voltage of 120V. 

Got an Electrical Project? We Can Help!

Before you pull any wires or breakers out from the wall for a DIY project, it is best to consult an electrician first. At U.S. Electric, we have certified electricians that can help answer questions. 

We’ve been in the electricity business for over 30 years in Richmond, VA. So if you need help with an electrical project, reach out to us. We’ll be happy to help with our guaranteed services!