How Many Outlets Can I Wire on the Same Circuit?

The best way to determine how many outlets you should install on a circuit is to consider what you will use those outlets for. Large, power-intensive appliances like heaters and dryers require much more wattage than lightbulbs or computers. Install fewer outlets on circuits that supply power-intensive appliances.

The National Electrical Code’s guidelines don’t specify a specific limit to the number of outlets you can install on a single circuit. This is because the number of outlets matters far less than what those outlets are used for. As you wire your home and install outlets, you’ll have to plan your electrical layout room-by-room. Figure out how much wattage you’ll require from each outlet and calculate the remainder to determine how much you have left to work with – and how many more outlets you should install on a particular circuit. Here’s what you should know about installing circuits and outlets, including what to avoid, how much power your circuits and outputs can handle, and how to plan accordingly:

What Happens If You Have Too Many Outlets on One Circuit?

Potentially nothing. Outlets themselves do not draw power. It’s only when you plug devices into your outlets that they start transmitting electrical current. Therefore, you could potentially install all kinds of outlets onto a circuit – you would only start running into trouble when you started plugging appliances in. If you plug too and use many appliances at once on a single circuit, your demands will overload that circuit.

If you’ve ever tried to run an air conditioner, a table saw and a hair dryer (or other combination of devices) in the same room, you’ve probably experienced this. The circuit breakers in your home (hopefully!) shut off when overloaded to prevent electric shock and fire.

To keep circuits from constantly tripping in your home, plan for the number of items you’ll need plugged in and how much power they will require. Large appliances like dishwashers and dryers require a dedicated circuit that serves their power needs exclusively.

How Much Power Can My Circuits Take?

Time for a little home wiring 101. There are three measures of electricity you need to understand to answer the question:

  • Amps measure the amount of electrical current.
  • Volts measure the force of electrical current.
  • Watts measure the power of electrical current.

If you think of electricity as water flowing through a pipe, the amps are the water volume, the voltage is the water pressure, and the watts are the amount of power the water can provide. The formula for calculating watts (the #1 thing to watch) is:

Watts = Volts X Amps.

So how does this affect your electrical outlets? Home circuits are either 15-amp or 20-amp circuits that run at 120 volts. The number of amps is printed on each individual circuit breaker switch in your electrical box. To determine how many watts of power they supply we multiply:

15-amps x 120 volts = 1,800 watts of power
20-amps x 120 volts = 2,400 watts of power

However, it’s recommended that you only use 80% of that potential power to account for potential power surges and overloads. That means:

A 15-amp circuit should be designated for 12-amp load or 1,440 watts.
A 20-amp circuit should be designated for a 16-amp load or 1,920 watts.

How Much Power Will I Need From My Outlets?

Now you know how much power your circuit can provide. The next step is to determine your power needs. This depends on how many people live in your home and which devices you’ll plug in and draw power from at any given time. Electric devices often have the watts required printed on them. Light fixtures are an easy one, as bulbs usually run at 40 to 60 watts. Here’s a few common devices and the average number of watts they draw from your circuit when you plug them in.

  • Electric heaters: 1,500 W
  • Refrigerators: 1,000 W
  • Microwaves: 1,000 W
  • Hair Dryers: 1,200 W
  • Computers: 200 W
  • 32” LCD TVs: 55 W
  • Electric Dryers: 4,000 W
  • Video Game systems: 100 W

These are all averages to give you an idea how much power you might need on a circuit. Look at your specific device for the exact consumption. As you can see, it’s important to balance large and small devices and why larger appliances like a dryer require its own circuit. Now you can upgrade your outlets as necessary.

Adding Electrical Outlets to Your Circuits

If your home’s wiring is up to date with the proper gauge wiring and grounding, adding or replacing outlets is relatively easy for a DIY person comfortable with electricity.

The first important step is to determine what type of outlet you need. Outlets are rated for 15 amps or 20 amps so look at the circuit breaker to determine which you’ll need. If you’re installing an outlet in an area where there is moisture like a bathroom, kitchen or laundry room, you will need to use a ground fault circuit interrupter (GFCI) outlet. These are the outlets with the “test” and “reset” buttons on them. They will shut off if moisture interferes with the flow of current.

Once you have the proper outlet, follow these steps:

  1. Shut off the power source at the circuit. Use a night light or voltage tester to make sure the power is off to the existing outlet.
  2. Remove the wall plates and housing screws on the existing outlet.
  3. Remove the outlet from the wall and unscrew the wall wires.
  4. Attach wires from the wall to the new outlet as they were in the previous outlet. If you are installing a new outlet, follow the included wiring diagram and these rules:
    – Black wires carry the power and attach to the brass screw
    – White wires are neutral and attach to the silver screw
    – Green or bare copper wires are grounds and attach to the silver screw
  5. Secure the outlet in its housing and replace the faceplate.
  6. Switch the power back on the circuit breaker.
  7. Test that the new outlet works.

Upgrade the Outlets in Your Twin Cities Home

Learning about how circuits, outlets, and wattage work can tell you a lot about how your own electrical system functions. For instance, if you feel like your circuits break too frequently, then it may be because you’re demanding too much wattage from them. On the other hand, if you don’t have enough outlets, then it may be possible to add more – or redistribute the load to optimize how you use them.

Most importantly, remember: you don’t have to figure out your outlets and circuits yourself. When it comes to redistributing electricity, installing outlets, or rewiring, it’s always a good idea to get professional help. The licensed electricians at EarlyBird are always available to help take the, ahem, load off of your shoulders. If you want help with any electrical wiring project, get in touch with EarlyBird right away. We’ll get you set up right – guaranteed.