How Many Outlets Fit on a 15-Amp Circuit? What About 20-Amp?

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Find out how many outlets you can add to a single circuit with this simple guide
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If you’re doing some home renovation or you’re designing your dream home, you may want to know what the rules are surrounding circuit allocations and outlets. How many normal outlets can fit on one circuit? What about fancy outlets, like the one you need for a dryer or washing machine? If you’re looking for straightforward answers, you’re in the right place. In this article we’ll break down everything you need to know about outlets, amperage, and your fuse box.

Things You Should Know

  • Run 8 outlets to a standard 15-amp circuit. On a 20-amp circuit, run 10 outlets.
  • There are no national requirements in the building code when it comes to the maximum number of outlets per circuit, but check your local codes.
  • Spread your outlets over as many circuits as you reasonably can to minimize the odds you trip your circuit breakers.
  • Identify whether a circuit is 15- or 20-amp by checking your fuse box. The amperage will be listed on the handle of each switch or on the panel of the door.
Section 1 of 5:

How many outlets can go on a 15-amp circuit?

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  1. You can theoretically run any number of outlets to a 15-amp circuit, but there are practical limitations here. On a traditional 15-amp circuit, each outlet can draw 1.5 amps—that’s 10 outlets. The 80% rule (used by electricians) says you should only use 80% of a circuit’s total allowance, so that takes us to 8 outlets.
    • When you picture a normal, typical outlet, you’re imagining a 15-amp outlet that’s wired to a 15-amp circuit at your electrical panel. If your outlet's top left prong has a "t" shape rather than a slit, then it's not a 15-amp.
    • The problem isn’t the number of outlets—it’s the total amperage being used. Having 20 outlets on a single circuit increases the odds you’ll accidentally plug too many things in.
    • If you overload a circuit, you’ll blow the fuse and lose power. It’s not dangerous if your home is wired correctly, but it’ll sure be annoying if you have to keep going down to the basement to flip the fuse.
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Section 2 of 5:

How many outlets can go on a 20-amp circuit?

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  1. Unlike 15-amp circuits, 20-amp circuits are typically reserved for heavy appliances and outlets where you need access to a massive electrical current . [1] Since there’s room for more amperage on the circuit, you can run roughly 10 outlets to one of these circuits.
    • 20-amp outlets look identical to your 15-volt outlets with one exception. The top-left prong will have a T-shape, not a narrow slot.
Section 3 of 5:

Building Code Rules for Circuits

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  1. Most cities have their own regulations when it comes to building inspections and whatnot. While some cities don’t specifically address how many outlets you can run to a single circuit, many of them do. The most common maximums are 8 outlets on a 15-amp circuit, or 10 outlets on a 20-amp circuit.
    • Most electricians will abide by the 8 and 10 rules as a default unless you ask for specific allowances.
  2. The NEC does provide minimums on the number of outlets required for kitchen countertops, but there’s nothing on the maximum number of outlets allowed per circuit. That doesn’t mean you can put an unlimited number of outlets on a circuit, though—you probably have local codes.
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Section 4 of 5:

Identifying Circuit Amperage

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  1. Go to your electrical panel (it’s usually in the basement or a closet). Pop the cover open and look at the individual switches. On top of each switch, there should be a 15A for 15-amp or 20A for 20-amp. If the switches themselves aren’t labelled, look on the fuse itself or the inside of the door for labels. [2]
    • If you see a 60A that’s a 60-amp circuit. It’s your fuse box’s main supply and provides overload protection for your home. You may also have a 60-amp circuit for your furnace, too.
Section 5 of 5:

Home Wiring Tips

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  1. Working on your fuse box is not a basic DIY job. There is a dangerous amount of amperage running through your circuits, and you could seriously injure yourself if you make a mistake. On top of that, you run the risk of an electrical fire if you make a mistake hooking up the wires. [3]
  2. Divide the rooms where you plan on using the most electricity over multiple circuits, and combine rooms where you’re almost never going to use close to a full load. Use as many slots on the fuse box as you can to ensure your home’s electrical system is never under unnecessary stress. [4]
    • Unless you accidentally run a hair dryer, radio, and a bunch of chargers on the same circuit, you should never actually trip a fuse. Spreading the load minimizes the odd this happens.
  3. If you use up every single slot on your fuse box, you’re going to have no room for error in the future. Having a few free slots will allow you to split a room’s outlets up if the fuse keeps tripping, or you add appliances or outlets in the future. [5]
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      References

      1. ↑ https://portal.ct.gov/-/media/DAS/OEDM/2018-CD-HO/FA18-Residential-Electrical-Inspections---2-Slide-Handouts.pdf?la=en
      2. ↑ https://iaeimagazine.org/2006/november2006/what-do-the-markings-on-circuit-breakers-mean/
      3. ↑ https://www.cpsc.gov/s3fs-public/518.pdf
      4. ↑ https://www.cpsc.gov/s3fs-public/518.pdf
      5. ↑ https://www.cpsc.gov/s3fs-public/518.pdf

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