How Many Lights On A 15 Amp Circuit: All You Need To Know

A question that often plagues the mind of most homeowners and amateur electricians is the planning of the circuit. If you do not plan the circuit in an efficient and safe manner, it can lead to many problems and could even lead to accidents. But how many of us know how to properly maintain a circuit? How many lights on a 15 amp circuit?


A home is only a dream home if it is safe and secure. There are a lot of factors that affect the safety and security of the house and the people living inside it. One such factor that you should be careful of is the electricity of your house.

It is extremely important to use electric circuits properly and efficiently. This can reduce the chance of short-circuiting or overloading. There are a limited number of appliances and light bulbs that can be used in a circuit without causing any accidents. When planning and installing electrical circuits and appliances, it is important to be careful and informed. You can even take the assistance of your electrician for this.

How to find the number of lights that can be used in a circuit?

How many lights on a 15 amp circuit that can be used? Firstly, we have to find the capacity of the circuit. As the circuit is 15 amps and functioning under a potential difference of 120 Volts, the capacity of the circuit is 15*120 or 1800 Watts.

how many lights on a 15 amp circuit

In the case of a 20 amp circuit, functioning under the same potential difference of 120 Volts, the maximum capacity of the circuit is 20*120 or 2400 watts. But most electricians only recommend that you use 80 percent of the total capacity. This is the maximum safe load of the circuit. It improves safety and security by giving a gap in case of power spikes.

how many lights on a 15 amp circuit

This means that you can utilize 1440 watts from the above mentioned 1800 watts. Thus, you can connect up to 14 lights that have a power rating of 100 watts each or 22 light bulbs of 65 watts depending on your need. But it should be noted that this is calculated assuming that only light bulbs are connected to the circuit, and no other device is connected.

How many new lights can you connect to an in-use circuit?

The detail mentioned above is only for a circuit that only has light bulbs. But this is seldom the case in our house. There are many light bulbs, fans and other appliances that are connected to the circuit which we should take into consideration.

So, ​how many lights on a 15 amp circuit that already has so many applications connected to it?

how many lights on a 15 amp circuit

You have to measure the amount of energy being taken by the other devices in the circuit. Switch on the light or device in the circuit which you want to measure. Then, open your electric panel. Start switching off all the circuits till you find the breaker for the circuit that you want to measure.

how many lights on a 15 amp circuit

Now, find all the appliances and other lights that are connected to that circuit. Take a note of all the devices in the circuit and calculate the total electric energy requirement. If there are 3 devices of 400 watts connected to the circuit already, then it leaves 240 watts to be used by the new lights. Some circuits might be highly loaded while others are not so overworked.

The Importance of using the correct number of lights in a circuit

There are many reasons why using the correct number of bulbs in the circuit is crucial. The most important of the features is safety and security.

how many lights on a 15 amp circuit

If you connect more than the recommended number of light bulbs and devices to the circuit, there is a really huge chance of the circuit overloading. And this can shut down and stop the working of all the appliances. It can even lead to overheating of the circuit and an explosion or fire in the worst case.


It is extremely important that we make informed and smart decision when it comes to our house and its safety. This is especially true when it comes to electricity. Electricity can prove to be devastating if not used properly and safely.

Make sure that your loved ones and family is always safe on the walls of your house. You should know about the circuits at your home and the importance of keeping it from overloading.

Follow the method mentioned above to know how many lights on a 15 amp circuit in your home. If you have any more questions or comments, please contact us through our comments option.

Abigail Jones

Hi, I'm Abigail. I like spending time tearing my house apart and putting it together back again. Join me on home improvement tutorials, tips on my blog.

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