Three Way Switch and Ceiling Fan in a Kitchen

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  #1  
Old 03-10-07, 02:24 PM
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Three Way Switch and Ceiling Fan in a Kitchen

Hi all, I've got a question I think others might also benefit from.

I am replacing the ceiling light in my kitchen with a typical ceiling fan and light fixture.

Currently, the light is controlled with a typical three way switch from two single gang boxes.

I would like control of the light and fan speed from the wall in the easiest way possible while having both switches turn on the fan and I have an idea.

I plan to replace the single gang box that contains the hot wire to the fixture with a double box, run an extra 14/2 from the fan to this new box, and then pigtail the output of the three way switch (i.e. the hot wire to the fixture) both to the light via the old wire and through a second ceiling fan speed switch.

This way, the fan will turn on from both of the original three way switch locations with the light but the speed can also be controlled from the wall. The only downside is that the fan cannot be turned on independent of the light. But I avoid having to install a new three way switch system for the fan with additional travelers and boxes.

I think all I am really asking is, is it ok to have two switches in series?
P.S. I'm an engineer and I am comfortable with electrical work but I have no formal training, just what I read. Just want to make sure I haven't dreamed up something unsafe.

Thanks,
John
 
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  #2  
Old 03-10-07, 02:34 PM
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I didn't quite understand everything you said, but yes, it's okay to put two switches in series.

You do realize that there are a bunch of different ways that a pair of 3-way switches and the fixture it controls can be wired, right? Make sure you know exactly which of those ways yours is wired before you start.
 
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Old 03-10-07, 02:36 PM
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Yes you can have two switches in series.

No you cannot wire this in the manner you have suggested. What you propose will work electrically, but is unsafe.

If you want what you have proposed, then completely replace the existing wire from the switch to the light. If it is 14-2 then replace it with 14-3. If it 14-3 then replace it with 14-4 (or 14-2-2). Use the extra conductor in this cable for the fan hot wire.

However, I caution you that you will likely regret your decision. Running the light all th time the fan is on is a wastes of power and a heat generator.

Instead of your idea, you might consider powering the fan switch from the always hot wire, do that the fan can be turned on or off without regard to the light.
 
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Old 03-10-07, 02:51 PM
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Thank you for your reply. This is a great forum.

Several comments.

First, I want the fan and light to come on and off together from both wall switches for convenience (which are on either side of the kitchen). It could get kind of annoying to flip the light from one side and have to go to the other side for the fan.

Yes I do waste some power having the light on whenever the fan is on, but I get the convenience of having the fan and light powered from either switch. After all, I am putting CFLs in anyway.

Also, would you explain why this idea is unsafe? How is this any different than having a remote control for the fan, which is really just a second switch. It seems to me the only difference is that my fan switch is in the wall instead of in the fixture.

Much appreciated.
John
 
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Old 03-10-07, 03:20 PM
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It generally safer to have all the conductors of the circuit in one cable. In the event of a fault, it can make the breaker trip just a hair sooner because of reduced magnetic fields.

I'm not so sure I'd call your proposal "unsafe". I think the difference is small.

But I have to say that I'm not exactly sure what you proposed. Do you intend to use one wire or both wires in your new cable?
 
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Old 03-10-07, 03:26 PM
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As I read your post, you plan to use only one conductor in the extra 14-2 cable you plan to install. That is why I used the term unsafe.

In a residential electrical circuit, the current flowing one direction is supposed to equal the current flowing the other direction. If you use just one conductor in a cable, this is obviously not the case. Any current flowing through that one conductor will not have current flowing the other direction through the other conductor. Further, in the already existing cable you will also have an unequal current situation.

Perhaps my use of the word unsafe was a little strong. Regardless, I still recommend pulling a new cable that has the proper number of conductors.
 
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Old 03-10-07, 04:01 PM
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Ok, forget what I said about the 14/2. I'll explain why I proposed it but regardless I think I have figured out what you are saying. You are saying I should run a 14/3 to my new box and that it would be ok to power the fan speed switch from the output of my light switch, thus extending the three way switch to the fan.

Sorry to be confusing but all I am really proposing is that I take the output of the three way switch that went to the original light and splice it to the two hot wires of the 14/3 with one wire going directly to the light and the other going through a fan speed control switch.

The reason I had the idea with the 14/2 is that my original box and fixture was off center and my new celing fan box is a pancake box directly under a joist. Unfortunately space is limited for all of the wires and it is several feet from the old fixture (too far for the original wires) so I left the original box and its connections and put a new wire going from the old ceiling box to the new ceiling box. So I will just run 14/3 to my old ceiling box and then to my new ceiling box, to add the fan wire.

You aren't thrilled that my ceiling fan can't be powered independently of my light but I think the convenience of being able to control the fan and light together from both of the original three way switches at either end of the kitchen outweighs this problem.

Thanks for helping me think this through.
 
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Old 03-11-07, 05:51 AM
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Whether your ceiling fan requires the light to be on is your choice. I mentioned it because I would not want it that way, and more importantly my wife would not want it that way. If you are okay with that then by all means go that route.

As has been stated, you can take the output of the switch (the switched hot wire) and split it. Electrically, splitting it at the switch output is no different than splitting it at the fan/light itself.

My original concern with your plan is the cables used. I am recommending a single cable so that all the wires uses are in the same cable assembly. As John stated, this is an issue involving EM radiation.

As additional concern is with box fill. You are limited to the number of wires that may enter a box. The limit is based on the volume of the box, the size of the wires used and any devices that are in the box. Another issue is with physical box space. The more wires, the harder it is to fit everything inside. Using two cables when only one is required increases the number of wires inside the box.

Finally, your comment that the new box is "several feet from the old fixture" is another concern. Understand that you can leave the old box in place, but that it must be permanently accessible. You cannot just place a box between the joists and cover the location with drywall. If you have an attic or crawl space above the kitchen then you are probably okay. Otherwise, you must leave the old box in place, accessible from the kitchen, and install a blank cover plate.

Good luck with everything.


My new concern is with
 
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Old 03-11-07, 11:49 AM
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Can you say remote control? Before I did all that rewiring, I would install a canopy held remote with the control on the wall, buy an additional remote, match the dip switch and mount it on the other wall.
 
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