We all do it at some point. There are times when we just have to plug a couple of power strips into a 4-way outlet adapter to make one outlet into enough plug-ins for all of our gadgets. However, most of the time we end up tripping the breaker and finding out that you can only plug so many things into a pair of electrical outlets. At this point, we usually wonder “how many things can I plug into one outlet?”
The Danger of Overloading Electrical Outlets
Plugging too many electrical items into one outlet 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 caused by overloaded electrical outlets.
The reason for this is in electrical current. When too much electrical current is flowing through a circuit, the conductor starts to heat up to 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.
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, you’ll want to map your circuit breaker panel 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 find out the voltage of the electrical outlets you want 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 up 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?
What you’ll need to find in order to know if you’re overloading a circuit or not is the amount of current you’re drawing from it. Current is expressed in amps. You can find the amperage you’re drawing from a circuit by adding up the wattage of all the devices on the circuit and dividing 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. You also see that the circuit is 120 volts. The other two outlets are empty. You want to use a 3-way adapter plug in another 150-watt lamp into the same outlet as the heater and the first lamp. So, you first need to add up the wattage of what’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.