How Do I Wire a 3-Way Switch to Control a Light PLUS Keep a Duplex Receptacle Hot

This is a question from a site visitor who was wanting to know how to wire a specific 3-way configuration.  The twist comes with the addition of a new duplex receptacle which he wanted to keep ‘hot’ all of the time, while still controlling a light with the 3-way switch.  This article describes the possibilities of this scenario and the steps to take.

Q: How do you wire a new duplex receptacle from a 3-way switch so that the new receptacle is always hot and the 3-way switch continues to only control the light fixture?

A: You may not be able to accomplish this, depending on how this 3-way circuit is wired.

The only way this will work properly is if the power source for this 3-way network enters this box first.

If not, you might have switched ‘hot’ conductors only, or if you do have a neutral, any of the hot conductors that you attempt to splice in to will not be hot all the time (it will depend on the switch positions).

You need to determine how the circuit is wired. If the power source does enter this box, then you could add a receptacle providing the box is large enough (deep box) to accommodate these additional wires because a normal sized metal switch box can only have 5 wires in it, and you will add two making a total of seven.

Here is a diagram of how this receptacle could be added in the proper circumstance.

How To Wire a Switch/Receptacle Combo Device

Lately I have had many site visitors asking me to write an article on how to wire a duplex switch and receptacle combination device.  While the switch/receptacle combo device is not common in the home, they have several unique applications where they can be very useful!

As with any electrical project, make sure that you take all necessary precautions, most important being to make sure you shut off the power.  Always review the safety page on our website.

Another valuable resource available on our site is “The Basics of Household Wiring DVD”, which is also available as an instantly downloaded e-book.  Follow this link to get your copy.

The switch/receptacle combo device is set up like a duplex receptacle, but has a 15A single-pole switch in one half, and a single 15A, 125V receptacle in the other half.  They can work in conjunction with one another, or they can be connected and used independent of each other.

Here is a diagram showing the internal function of the switch/receptacle combination device.

Here is an actual picture of a Leviton Switch/Receptacle Combination Device.

I will discuss three different possible scenarios where a switch/receptacle combo device such as this would come in handy.

Scenario #1

In your garage or shop, you would like to install a task light, like a florescent light fixture over workbench.  However, the walls are all finished so getting a new wire to a switch and then up to the light is not that simple.  However, you have a receptacle just above the bench that you can get your power source from.

You can change this duplex receptacle to a switch/receptacle combination so that you still have power in the outlet, but can use the switch to control your new overhead task light.  Fishing in a wire from the receptacle to the light fixture is fairly easy, so this is how you would wire the switch/receptacle combo device in this situation.

Scenario #2

A typical example of this situation is if you had the same scenario as above, but with a 3-wire circuit, such as in a kitchen split receptacle, and wanting to add some under-counter lighting for example.

Just as the receptacle that you replaced will have the tab on the hot side removed, here we have to remove the tab on the device as well.  This will put the light on a different circuit as the receptacle, but again will give you the desired result of a usable receptacle, and a switched light fixture without a difficult wiring renovation.

Keep in mind that this isn’t the best situation, as you now lose the required amount of circuits in the kitchen. However it is an example of how we can have the switch and receptacle operating independently from one another on different circuits.

Scenario #3

Here is a situation where your desired result is a receptacle controlled by the switch in the combination device.

Let’s say you have a task light for your shop, and it is cord connected and designed to be mounted over your work area and then just plugged in to an outlet.  Instead of plugging the light in and out every time you want to control the light, this will allow you to keep it plugged in and use the switch for control.

So there you have three examples of where a switch/receptacle combination device like this can come in handy.

Outdoor Lamp Post Installation Questions

Installing an outdoor lamp post along a driveway is a terrific way to illuminate the exterior of your yard.  In addition to lighting a path to your home, this type of lighting can enhance the safety of your yard by letting you easily see any potential hazards, as well as deter any unwanted criminal activity.  The installation of an outdoor lamp post is one of those DIY projects that can be safely taken on by a competent DIYer.  I recently received an e-mail from one of my website visitors who had a question regarding the installation of an outdoor lamp post; more specifically, whether it would be necessary to install an electricalbox along with the lamp post.  The following video and article answers this question.

Q:  I’m going to be installing an outdoor lamp post alongside of a driveway. I have a new lamp post assembly, which came with an 18/2 SJ cord prewired from its’ 3-lantern head down to the base of the pole assembly. The pole assembly will be mounted onto a 2ft deep concrete footing with a PVC conduit installed inside of the footing. A 14/2 NMWU cable will be run underground from the house to the lamp post.

Since the lamp post has an 18/2 SJ cord prewired down to the base of the pole assembly, I am wondering if the underground cable connection should be made at the base of the pole, where the prewired 18/2 SJ cord terminates –OR- should I remove the prewired cord, and run the underground cable through the pole to the lantern head? If the connection is to be made at the base of the pole, will it be necessary to install an electrical box on top of the footing where the base of the pole will sit? The base of the pole has also a large canopy. – Stephen

A:  Stephen, the base of the lamp pole itself is an approved junction box for the termination of the underground cable and connection to the SJ cord that is prewired from the lantern heads on down to the base.  When fixtures get appropriate approvals from accredited agencies, they approve the entire fixture as a whole, and a suitable location for the electrical connections is a part of that inspection.

You could run the NMWU cable up to the lantern head, but only if that is more convenient for you in some way, like easier access to the splice should something go wrong.  The advantage of that would be one less set of splices, thus one less potential trouble spot.

The only issue you may have in your project is the size of the underground wire.  I would check with your local electrical authority to make sure that #14/2 is large enough.  Some jurisdictions specify that 12 gauge wire is the minimum size allowed for underground installations.

So in conclusion here; no, you do not need to install a junction box on top of the PVC conduit at the base of the footing, the fixture itself is approved for the electrical connections.  Enjoy the light and good luck with the outdoor lamp post installation project!