Switched Outlet Wiring (Type 1, Electric Starts at the Receptacle)
February 2, 2009 | by Fred (email) |
Switched outlets are very common in today’s homes. The primary motivation for this wiring setup is money savings for builders by not installing overhead light fixtures. Instead, builders wire a switch to one or more outlets in a room with the intention that homeowners will install floor or table lamps. (This meets the National Electric Code (NEC) requirement for a switched light in every room, except for the kitchen and bathroom which must have overhead lights.)
There are two common ways to control a receptacle with a switch. The appropriate way is dictated by where the electricity enters the circuit (either at the switch box or the receptacle box). The diagram below shows proper wiring when electricity runs to the receptacle first.
This is the first of two articles. In the second, I describe how to modify this setup so that the switch controls an overhead fixture. This is done by running only one additional Romex from the switch to a new overhead fixture, such as a ceiling fan.
Note that I’m not a licensed electrician, just a bit of an electrical junky. You should always consult a licensed electrician for any electric work in your home that you are not qualified to perform. In any event, use this information at your own risk 🙂
Wiring Diagram – Electric Starts at the Receptacle (Plug)
Switched Outlet Diagram Explanation
- A – Standard 2-wire (+ ground) Romex runs from the main breaker panel to the receptacle box, and from the receptacle box to the switch box. For 15 amp circuits, use 14 gauge wire. For 20 amp circuits, 12 gauge wire.
- B – The black (hot) wire from the main breaker box is wire-nutted to the white wire in the Romex running to the switch. Note, this makes the white wire at the switch “hot”.
- C – The black and white wires of the Romex running to the switch are coupled to the two poles on the switch. On most switches, the order in which these are installed is not important, since the switch serves only to sever or join the circuit. Note that after these are connected to the switch, the black wire becomes “switched hot.”
- D – The black (switched hot) wire from the Romex running from the switch is connected to the gold terminal on the receptacle. The receptacle is now powered by switched hot current.
- E – To complete the circuit, the white (neutral/common) wire from the main breaker panel is connected to the silver terminal on the switch.
- F – Bare copper (ground) wires in the receptacle box are nutted with a third wire that runs to the receptacle itself. Ground wire in the switch box is connected to the switch itself.
Switched Outlet Quick Tips
- Remember the saying white going out, black coming back. That is to say, that voltage should run up the white wire to the switch, and come back to the receptacle on the black wire as switched power.
- Note that the receptacle can be divided such that the top and bottom of the receptacle are on different circuits. In this situation, sometimes the black (hot) wire from the main box is fed directly to the top of the receptacle, and then switched current is provided to the bottom receptacle.
- Switched power can be provided to other receptacles in the circuit by running Romex from the receptacle box to additional receptacles down the line.
A Good Electrical Resource
What do you think? Did this article help you out?
@ Fred – Nice easy instructions! We actually build new homes for our customers with an overhead fixture along with the ability to have switched outlets behind the bed for table lamps. We run a 3 wire to the outlet which allows us to switch one or both of the receptacles. Some people choose not to use the switch while others like the added flexibilty.
Todd – sounds like you guys build higher quality homes than most. I like it when builders go with the 3-wire setup. Gives maximum flexibility to homeowners. Unfortunately, you’ve got to factor in the cost of the additional copper, but it’s an expense I’d be very willing to pay.
Fred – Our electrician actually does this as standard practice. He’s found over the years that it’s easier / cheaper to run the 3 wire from the beginning. This eliminates difficult changes later on. Most home owners end up “wishing” they had a switched outlet or some combination of them after the fact. It’s a cheap investment to head off expensive and time consuming changes later.
Fred, This was a very well written post. Easy directions to follow allowing any DIY homeowner to feel comfortable doing something like this. One note that i will add to this: When dealing with switched outlets you always have to be careful to pay attention to if the outlet’s “bridge” has been cut and the outlet’s has the top switched and the bottom hot, If you replace the outlet and do not cut the bridge if it was cut originally it could be harmful and at the very least it will trip the breaker. I have seen people make this mistake and it can be very dangerous. Much like Fred i am not an electrician, just speaking from DIY experience and from working with electricians.
I have to agree with both Todd and Fred on the fact that running 3 wire in the beginning is a lot cheaper and easier if there is the slightest chance you the homeowner would want to change to a switched outlet. Running wire after the fact can be costly, and it is probably an electricians least favorite things to within the job they do.
Thanks for the great post Fred and i look forward to more electrical posts!
whenever you do this, the white wire going from the outlet to the switch should be wrapped in black tape at both ends, to indicate that it is, in fact, hot.
Worked with my Dad as an elecrical helper when a kid- he’d get me going on tasks, but give little explanation on the “why”. Appreciate learning this from you guys! Andy and Joe’s comments bring back memories. Also, I remember the time Dad had me go wire an outlet that he said “wasn’t hot”. 110 volts might have been used as a disciplinary tool on a somewhat mouthy teenager?!