How Much Can I Plug Into One Electrical Outlet?

Learn about how to safely use electrical outlets.

We all do it at some point. There are times when you just have to plug a couple of power strips into a four-way outlet adapter to make sure you have enough plug-ins for all your gadgets.

However, you might end up tripping the breaker. You learn the hard way that you can only plug so many things into a single outlet.

At this point, you usually wonder how many things you can actually plug into an outlet. Find out with this guide from Blain’s Farm & Fleet.

The Danger of Overloading Electrical Outlets

When there are too many things plugged into one outlet, it can do more than just trip a breaker. There’s actually a serious risk of an electrical fire if you overload a circuit with too many gadgets.

The United States Consumer Protection Safety Commission reports that there are over 5,000 electrical fires in American homes each year that are caused by overloaded outlets.

The reason for this has to do with electrical current. When too much electrical current is flowing through a circuit, the conductor starts heating up. This is so it can disperse the energy that it can’t conduct.

This heat can build up until the conductor, whether it’s a wire, an outlet, or any other part of the circuit, gets hot enough to start a fire.

This is why homes are equipped with circuit breakers and fuses. Breakers and fuses detect the amount of current in the circuit. And they cut the connection if the current level gets too high.

How Much Is Too Much?

Finding the answer to this will require you to learn a few things about your home’s electrical setup.

How many amps can the circuit breaker handle?

Since you’ll need to do a calculation based on everything plugged into one circuit, it’s a good idea to map your circuit breaker panel. This is so you know which outlets and lights in your home are connected to each one.

Find the amp rating of the circuit breaker that governs the outlet you’re plugging into. The amp rating of most circuit breakers is 15 or 20 amps.

What is the voltage of the circuit?

You’ll also want to figure out the voltage of the electrical outlets you plan to plug into. The ones that look like a standard plug with vertical prongs are 120-volt outlets. And outlets that fit a plug with diagonal prongs are 240-volt.

Voltage is often described as the “pressure” of the electricity in a circuit. An easy way to think of it is the higher the voltage, the more “power” the circuit can deliver.

How many watts are you trying to get out of the circuit?

You’ll have to add the wattage of each device plugged into all the electrical outlets on the circuit. Make sure you include the bulbs in any light fixtures in the circuit, as well.

How much current are you drawing from the circuit?

To know if you’re overloading a circuit, you need to find the amount of current you’re drawing from it. Current is expressed in amps.

You can find this by adding the wattage of all the devices on the circuit. Then, divide it by the voltage your house supplies.

The formula for finding how many amps you’re drawing is:

[Total Wattage of Devices Plugged Into the Circuit] ÷ [Voltage of the Circuit] = [Amps Drawn from the Circuit]

So, let’s say you’re running a 150-watt lamp and a 1,500-watt space heater on one outlet in your living room. From the map you made of your circuit breaker panel, you also see that there are two more electrical outlets and a 100-watt light running on that same circuit.

And you see that the circuit is 120 volts. The other two outlets are empty. You want to use a three-way adapter plug to use another 150-watt lamp in the same outlet as the heater and the first lamp.

So, you first need to add the wattage of everything that’s plugged into the electrical outlets and light fixtures:

150 + 150 + 1,500 + 100 = 1,900

So, you’ll have a total of 1,900 watts running on that 120-volt circuit. The amperage would be:

[1,900 Watts] ÷ [120 Volts] = [15.83 Amps]

This will be fine if the circuit is governed by a 20-amp breaker. But it will overload a 15-amp one, and you’ll have to plug the lamp in somewhere else.

For more safety tips and guides, visit our Electrical Blog.