Big houses, small houses, and even doghouses have different types of outlets. Well, maybe not doghouses. But then again, Snoopy did have Christmas lights, and that was long before solar power and battery-operated lights. So perhaps doghouses do have electrical outlets.

Electricity fascinated man since long before Ben Franklin tied a metal key to a kite string. We watch the power of lightning scream across the sky on a stormy night. Static electricity from our carpeting makes our hair stand on end. Children stand transfixed for hours running their tiny fingers around the surface of a plasma ball at the local science museum.

Don't Poke Your Finger in It

poking outlet

There are two types of electrical current. Direct current (DC) derives its power from a single, stand-alone source, such as a battery. DC power is supplied on-demand but remains in a dormant state when there is no demand. Alternating Current (AC) gets power from a central power distribution center, which travels through lines and is always active. The lines in your house carry current even when nothing is plugged in or turned on.

We put plastic covers over outlets to protect our toddlers. Those little holes are so inviting to poke little fingers in. I poked a bobby pin into one as a kid. Forgive me if I say it was a rather shocking experience. I got knocked on my little keester, the fuse blew from the surge and knocked out power in half the house. That was not the way to check a live circuit.

Checking a live circuit

checking outlet

If you are buying a house, one of the things you should be doing is checking all the wall outlets. There is a safe way to do this, with a specialty tool called a circuit tester. They start out around $5 to $10 for a dual-pronged tester that can check 110 volts, 220 volts, 277 volts, and 460 volts. Professional models used by electricians can cost hundreds of dollars.

This tool can be inserted into any wall outlet to let you know if there is an active current. When working with electricity, knowing when a circuit is live is very important. Isolating a breaker or fuse to interrupt power to the circuit allows you to change electrical components safely.

Safety first -- turn off that breaker

turning the breaker off

Isolating a breaker, especially if your breaker box is not labeled, is easier with two people. If you are working alone, wear your Fitbit so you can count all the extra steps.

With two people, one will stand at the breaker box. The second person, with a circuit tester in hand, will be in the room where you intend to perform electrical work. If the breakers are labeled correctly, the person by the box should turn off the switch labeled for that room. The circuit tester should be used to check the outlets to make sure that there is no power at the outlet.

If the breaker box is not labeled (which is more often the case), the person at the breaker box should turn off one switch at a time while the person in the room tests the outlets. Once the outlet shows no current, have the person at the breaker box label that breaker for that room. While more than one room may be on a single breaker, this will help you in getting your breakers all labeled eventually.

If your house is old enough the have fuses, the same procedure applies, but the fuses get removed as opposed to switching a breaker off.

If you are working alone, follow the same steps as above. But you physically have to go to the box, turn a switch, then return to the room to check the outlets. If you turned off the wrong switch, head back to the breaker box and try the next one. See why we said to wear your Fitbit?

Old House Blues and Ungrounded Circuits

If your house is more than 60 years old, there is a very high probability that your electrical system does not contain grounded circuits. The National Electric Code (NEC) first required the grounding of all newly installed 120-volt electrical outlets in 1962. It is still legal to replace ungrounded two-prong outlets with a new two-prong outlet. Most contractors will install a three-prong outlet and ground it manually to maintain safety standards.

How to ground an ungrounded circuit

First, see if the box containing your outlet is grounded. The testing procedure is to insert one prong of your circuit tester into the smaller vertical slot on the outlet (this is the hot side). Touch the other prong to the screw in the center of the mounting plate. The box is grounded if your tester lights up. If your tester doesn't light up, install a GFCI outlet and do not use that plug for sensitive electronic equipment.

Remember that breaker you found earlier? Go turn it off now. Remove the old outlet and then remove the electrical wires. Look for the brass terminal on the new outlet and attach the black wire (this is the hot wire) to that screw. Attach the white wire to the silver screw.

To attach the ground wire, look for a green screw at the back of the box. If there isn't one, you can purchase green screws and grounding pigtails at your local hardware store. Screw the grounding pigtail (an eight-inch piece of grounding wire) onto the green screw. Install the other end of the wire on the green screw on the outlet. Shove all the wires in the hole (carefully), then turn the breaker switch back on and check for current at the outlet.

What Types of Outlets to Install Where

You've decided to upgrade some of the old-fashioned outlets in your home (or maybe replace the one you accidentally painted over last year). You're in the hardware aisle of the local home improvement warehouse staring at the many types of outlets. There isn't an employee in sight. None of the price placards tell you precisely what you're looking at and how they differ. Never fear, help is on the way.

Standard 15 amp outlets are popular types of outlets. 

Standard 110/120 volt types of outlets

A standard outlet has two plug-in receptacles. In each receptacle, the left vertical slot (this is the neutral slot) is slightly larger than the right (this is the hot slot). A semi-circular hole appears below them in the center (for the ground prong). The plugs look like shocked smiley faces. Standard outlets are normally installed on 15 amp breakers. If you attempt to pull more than 15 amps of electricity through them, the breaker should "pop" or automatically switch to the off (safe) position. This safety feature keeps us from overloading circuits and burning our houses down.

If you have a 20 amp breaker, you can install a 20 amp standard outlet, such as the Leviton 20 Amp Industrial Grade Heavy Duty Self Grounding Duplex Outlet for example. These are almost identical to the 15 amp outlet. A good example would be the Cable Matters Tamper Resistant Duplex Receptacle 15 Amp Electrical Outlet with Wall Plate. But the 20 amp outlet has a horizontal slot extending from the center of the left (neutral) vertical slot.

20 amp outlet

Ground Fault Circuit Interrupter (GFCI)

A Ground Fault Circuit Interrupter (GFCI) is a specialized outlet designed to interrupt power to the circuit. Kitchens, bathrooms, or anywhere within three feet of a water source require the installation of a GFCI outlet. You will also find them in garages and on outside receptacles.

This type of outlet has two buttons in the center for testing and resetting the circuit. If a fault, or short circuit, interrupts power to the plug you must press the reset button to restore power. Pressing the test button will manually interrupt power to test the circuit to make sure it is operating correctly.

As mentioned earlier, a GFCI outlet can replace an ungrounded outlet. While this offers some protection, you should not use this plug with sensitive electronic equipment.

Arc Fault Circuit Interrupters (AFCI)


Another safety feature built into house electrical systems is the Arc Fault Circuit Interrupter (AFCI). These types of outlets are installed in the first position on a circuit leading from the breaker box. In the event of an arc, or power surge, the outlet will "trip" and interrupt power to all outlets on that circuit.

New home construction after 1999 requires the installation of AFCI outlets. This includes room additions to an existing structure. In homes constructed before 1999, the electrical system is exempt from this requirement.

Local Building Ordinances, Codes, and (Gasp) Inspections

Always be sure to check the building codes in your local municipality. You can perform most general electrical work without a permit. It is always better to check though, especially if you are changing the types of outlets in your home.

If you are adding additional breakers, changing the amperage of a breaker, or making structural changes you may need to obtain a permit, hire an electrical contractor, and undergo inspections at various stages of the work.

You're Ready to Start but Did You Check the Breaker?

Life is good. You've studied up on the types of outlets available. You have checked the local building code requirements, and you will not need a permit. The new outlet and a screwdriver are in your hand. You carefully remove the outlet cover plate. But wait, did you check the breaker?

While there are other types of outlets available for higher voltage circuits, we recommend you leave installation and replacement of those to a professional electrician.

We hope you enjoyed our adventure in the types of outlets and how to change them in your home. Let us know in the comments if there are other quick How-to or informational articles you'd like to see.