Can I retrofit a switch into this circuit?

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  #1  
Old 12-22-15, 01:00 PM
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Can I retrofit a switch into this circuit?

We have a utility closet in the basement, lighted by a pull-chain light built into the ceiling. The light is wired with romex on a 110v circuit. The pull-chain is annoying and we'd prefer a light switch.

The romex in the ceiling is exposed/visible and the walls are unfinished with visible 2x4 studs. Seems like I ought to be able to disconnect the existing romex from the light and run it down to a switch by the door, then run new romex from the switch up to the light.

Is this a DIY project for a capable amateur?

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Last edited by CycleZen; 12-22-15 at 01:28 PM. Reason: clarity
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  #2  
Old 12-22-15, 01:04 PM
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It's a very simple project if you have only one romex cable going into the light box. You can run the existing cable into a new switch box and run a new cable from the switch box to the light box. At the switch, the white wires get wirenutted, the grounds get wirenutted and the black wires go to the switch terminals. At the light, it's black to black, white to white, and grounds together and the box.

There are other options if the existing cable is not long enough.
 
  #3  
Old 12-22-15, 01:09 PM
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It would be easy to do with minimal skills. In order to meet the recent code changes you are required to have a neutral in the switchbox. To do this you have 2 options which I'll list below.

1. Run a length of 14/3 (or 12/3 depending on the size of breaker being used on the circuit) from the light to where you want to switch. At the light connect the incoming white wire (neutral) to the light fixture and to the white wire that will go to the switch. Take the black wire of the incoming power connected to the black wire of the new cable. Connect the red wire of the new cable to the light fixture. At the switchbox connect the black to one side of the switch and read to the other side of the switch. But they were nut on the white wire for future use.

2. Remove the existing cable to the light fixture and move it to where you want to switch. Connect the black wire to one side of the switch. Run a new cable (14/2 or 12/2 again depending on breaker size) from the switchbox to the light fixture. Connect the black to the other side of the switch to connect the 2 whites together with a wire nut. At the light fixture connect the white to one side and black to the other side of the fixture.

Either way is perfectly acceptable according to code and you can do whichever one is easier in your situation.

Please know I didn't mention the ground wires in my explanations but they should be connected to each device as appropriate.
 
  #4  
Old 12-22-15, 01:13 PM
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Hi, you can do it either way if you run the wire from the light down to the switch box, white wire will remain connected to the fixture,new cable should be a 3 wire (14-3 Romex) code wise, Red wire connects to one terminal on the switch, Black wire to other terminal on the switch, at the light Red will connect to the Brass terminal and the Black from the switch will connect to the Black at the light with a wirenut.
Hope this helps
 
  #5  
Old 12-22-15, 02:15 PM
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Cool! I'll do it, thanks for the info. I may also move the light to a more central location, or put in a flourescent tube light.

In the photo, the romex is lying on top of that horizontal stud, and staples onto studs and joists. Is it better form to drill through studs to run the romex? (I would not drill a joist.)
 
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Old 12-22-15, 02:19 PM
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The cable is up high, out of the way and is fine as it is. However, you can drill thru the floor joist too. A small hole..... approx 9/16" - 3/4" ..... would not affect the integrity of the joist.
 
  #7  
Old 12-22-15, 02:32 PM
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Got it. Does code dictate height of the switch, distance from door, anything like that?
 
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Old 12-22-15, 02:44 PM
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No it does not. .
 
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Old 12-22-15, 02:49 PM
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There is no code dictated height but it's customary to match the height of the other switches in the house.
 
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Old 12-23-15, 02:57 PM
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Had a few minutes today, and wired it in as described above... but no light. I turned off the breaker and immediately lost other devices on that circuit.

~ Disconnected the light, and saw that this light was not the terminus of the circuit, but that another length of romex was connected presumably to other devices down stream.
~ Moved the romex from the light to the new switch location.
~ Stapled the new romex run from the switch to the light.
~ At the light, wire nutted the white-to-white and ground-to-ground ends of the romex runs.
~ At the switch, wire nutted the white and ground ends of the romex runs. Connected black wires to poles on the switch.
~ Flipped circuit breaker on. Other devices on the circuit powered on, but the light does not come on.

Troubleshooting:
~ I have continuity between the poles of the light switch, and I tried a different switch too; no luck.
~ 120 volts between black and white on the romex leading in to the switch.
~ When I remove the switch, there is no voltage between black and black.
~ Circuit hot, switch installed, no power between poles with switch on, same deal with switch off.

For a brief moment the light did come on. Out of frustration with walking back and forth to the breaker panel I started to disconnect the switch while the circuit was hot (you're right, i should know better), and in the course of futzing with the switch the light sputtered on and off.

Is it a continuity break somewhere? Could a power surge cause a downstream socket or switch to fail?

Willing to entertain ideas and suggestions!

Thanks,
Dave O
 
  #11  
Old 12-23-15, 05:27 PM
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wired it in as described above
Multiple ways were given. Did you bring power in at the light or the switch?
 
  #12  
Old 12-24-15, 03:23 AM
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Got up early to go back and check my work, come to find out the power is to the light. Visualizing from the photo I ass*u*me*d power came in from left to right. Come to find out power is to the light, coming from "behind" using the photo as reference point.
 

Last edited by CycleZen; 12-24-15 at 03:57 AM.
  #13  
Old 12-24-15, 06:41 AM
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Then what you should lave installed is a basic switch loop.

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Power for any unswitched down stream loads from the light would be connected to the black and white at the light.

Any unswitched loads from the switch would be connected to black and white.
 
  #14  
Old 12-24-15, 11:34 AM
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Made some progress: the light switch now controls the light, but downstream devices are not getting power. This diagram shows what i've done. Yellow dots are poles on the lightswitch and lamp. Black wire from "downstream romex" and the 3-wire romex are both connected to the same pole of the switch: is that correct?

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  #15  
Old 12-24-15, 02:13 PM
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Your diagram looks correct because you have the black and white from the supply continuous to the downstream circuit. Obviously your drawing or your wiring is not correct because if it is the downstream devices should have power all the time.

Do the downstream devices have power when the switch is on or do they never have power?
 
  #16  
Old 12-24-15, 06:03 PM
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How did you determine which cable is hot? You can not use a non contact tester.
 
  #17  
Old 12-26-15, 10:26 AM
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Had to take a break yesterday, but looked into this again and found that what I *thought * were downstream devices are actually on a different circuit. My son was stationed at the breaker panel to power my circuit up and down, and must have turned a circuit off accidentally, so when i went to put tools away the lights in the garage were off and i thought it was related to my project. Everything working as expected now.

Thanks to all for responses!
 
  #18  
Old 12-26-15, 10:42 AM
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Glad to hear that you have everything working correctly! Thanks for giving us the update.
 
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