How to Make a Split-Wired Receptacle to Double Power

Wiring electrical outlets is a common, straightforward electrical project. With this task, the power from one circuit is delivered to a duplex outlet and is shared between the two sections of the outlet. But when you have a greater need for power at this outlet and want to avoid nuisance breaker trips, you may want to split up this outlet between two circuits.

What Are Split Outlets?

A split outlet is a duplex electrical outlet that is split into two sections so that each section receives power from its own separate hot or powered wire. The outlet body itself is not physically split; it remains intact. However, a small section of the outlet is physically split to separate the functions.

In homes with 120V systems, an outlet wired like this will have 120V in the top section and 120V in the bottom section, for a total of 240V coming into that outlet. This is in contrast to the more commonly found electrical outlet that has 120V shared between the two sections.

Most 15- and 20-amp (A) outlets are called duplex outlets because the top and the bottom sections can operate separately. Upon purchase, duplex outlets are not operating in duplex fashion. A terminal fin—a tiny strip of copper or most likely brass—connects the two sections. When one section receives power, so too does the other section because of that copper or brass strip. Severing the terminal fin allows for separate feed conversion.

Split outlets let you bring twice the amount of power to a single receptacle. This is especially valuable in kitchens, where you often find high-demand appliances. For example, the top section of a split outlet can power a microwave oven, with the bottom section powering a toaster. This reduces the chance of circuit breakers flipping off because of excessive power draws.

Codes and Regulations

Most communities require that you apply for an electrical permit for any type of electrical circuit and service extension or alteration. Wiring a split outlet in most cases will be either new construction work or an alternation, both of which require a permit.

When to Wire a Split Outlet

While wiring the split outlet is fairly easy, running the 12/3 or 14/3 electrical wire to the electrical box will not be easy if the walls are closed. The best time to wire a split outlet is when the walls are open, prior to installing the drywall.

Safety Considerations

Always be sure to turn off the circuits that you will be working with and double-check with the voltage tester that the wires are not live.

The 12/3 and 14/3 electrical wires are not always interchangeable. If you are working with a 20 A circuit breaker and a 20 A-rated outlet, be sure to use 12 gauge wire. (Note: the National Electric Code allows 15 amp outlets to be used on 20 amp residential circuits.) If you are working with a 15 A circuit breaker and a 15 A-rated outlet, you may use 14 gauge wire, though you can use 12 gauge wire, as well. (Note: You are not allowed to use 20 amp rated outlets on a 15 amp circuit breaker.)