A couple of years ago we had a customer who was offered a beautiful top-end electric range for free when his sister remodeled her kitchen. Fortunately (or not), he looked at the power cord for her range and checked to see if it fit the outlet in his home. It didn’t, so he called us to look at whether the outlet could be reconfigured. We noticed that he had a 240-volt, 30 amp range outlet and when we checked his breaker panel, we saw that the wiring wouldn’t support the 50-amp draw of the new range. Replacing the wiring would cost more than the stove was worth, so he had to turn down his sister’s generous offer.

Gone are the days when your home’s electrical outlets were a simple matter of 110 and 220 volts. Today, even the humble low(er)-voltage outlets, called convenience outlets, are designed for specific uses. Throw in 240-volt outlets and you could have over eight different outlet types in your home. Let’s look at them.

Powering Your Home’s Electrical Needs

The power coming into your home is typically 240 volts. It’s split at your main breaker box into 120-volt feeds for your regular outlets and switches and 240-volt feeds for high-demand appliances like ranges, ovens, dryers, water heaters, furnaces, and air conditioners.

120-volt household circuits carry either 15 or 20 amperes of current and can have several outlets on a single branch protected by a single-pole circuit breaker. 240-volt circuits run to a single outlet, typically carry 30 or 50 amps of power, and are protected by a double-pole breaker at the panel.

120-Volt Outlets

Older 110/120-volt outlets simply had two slots of the same size parallel to one another like this: | |. Later two-slot outlets had one opening longer than the other to accept polarized plugs: | |. Neither type had a third opening to connect to a ground wire. Neither meets today’s electrical codes and most should be replaced by a licensed electrician to assure they are properly wired.

Today’s 120-volt outlets must have both a polarized configuration and a grounding socket as well as tamper-resistant (childproof) closures in some locations that will only open when an appropriate plug is inserted.

120-volt outlets come in two slot types—one for 15-amp and one for 20-amp circuits. Other types include Ground Fault Circuit Interrupter (GFCI) outlets and Arc Fault Circuit (AFCI) Interrupters. Current building and electrical codes dictate which type of outlet is appropriate for different locations.

240-Volt Outlets

While a 120-volt outlet has a single “hot” wire with return (neutral) and ground wires, a 4-wire 240-volt outlet has two 120-volt hot wires, plus a return and a ground. Some earlier 220/240-volt outlets had slots shaped like a backward L and lacked a ground. Those circuits should be inspected by a licensed electrician and replaced if indicated to avoid potentially lethal shocks.

240-volt outlets are larger and usually round with a single plug-in designed to power a specific appliance and are typically rated for 30-and 50-amp loads. You may occasionally come across a 15-, 20-, or 60-amp, 240-volt outlet, too.

Like 120-volt outlets, 240-volt receptacles have pin configurations that indicate amperage and sometimes specific uses like for a clothes dryer or electric range. Others may have rounded slots that allow the plug to be locked into place by twisting it. As you can see in the chart below, there are over a dozen pin configurations for 240/250-volt outlets. Each is designed for safety in a specific application and are not interchangeable. That’s why you should always check both your outlet and breaker box before buying a high-voltage appliance to be sure that your home’s wiring will support the load and that the proper receptacle is installed.

Electrical Outlet Types Used in the USA Today

Need Help? Call a Pro

Electrical and building codes are there to protect lives and property and overlooking them can be both expensive and tragic. So why risk trouble when help is only a call or click away?

Remodeling, renovations, and additions need top-notch electrical work, and Allstar Electrical Services delivers the quality results you expect and deserve. We work hand-in-hand with you and your contractors to ensure your new project is done right, on budget and on schedule.

We’ve served the Front Range for over 20 years, are top-rated by the BBB and Angi®, and are proud to be a Home Advisor Preferred Contractor.

Whatever your electrical needs, call Allstar Electrical at 303.399.7420 or visit our website. Then use our handy on-line forms to request an estimate or set up an appointment.