Replacing Office Light Fixture with Standard Ceiling Fan

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Old 10-05-09, 09:35 AM
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Lightbulb Replacing Office Light Fixture with Standard Ceiling Fan

I am replacing one of the office-style, two-bulb, surface mounted neon light fixtures with a standard ceiling fan/light fixture. There is only one switch that controls the entire unit. The former office fixture had two whites, white blacks, and one ground, so a comparison couldn’t be made. I believe they had everything wired together, but the fixture dropped pretty fast and I didn’t have time to analyze it.

Here is a simple diagram of my system:


CONNECTION (biggest concern):
My problem is that I took the old fixture down and saw two cables instead of one. I attempted to hook the fixture to only one fixture and it threw the breaker (probably just a spatial issue due to the lack of a power box causing wires to touch). I am 99.9% sure that I need to just wire all whites (grey in the diagram), all blacks, and all grounds together, but I want some back-up on this before I go ahead. Any suggestions?

MOUNTING (would like some input):
The former fixture wasn’t placed one a mount because it had enough surface area to screw directly into my plaster ceiling. I am worried that any vibration in the fan motor will, over time, work any screws out of the ceiling if I attempt to forgo any type of stud mount of one of those braces you use for dry-wall ceiling mounting. My first question is “can I bolt the ceiling fan directly into the ceiling without doing any sort of extra demolition on the ceiling where the cables protrude?” and “if I need to place some sort of support for the fan, what are the best tools for creating the larger hole in a plaster ceiling and what type of mount would be easiest?”
 
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Old 10-05-09, 09:52 AM
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Is this in a commercial occupancy? If so for liability reasons you should hire someone properly licensed and insured to do this work.

You will need to determine where the 2 cables go before someone can tell you which connections to make. You may have a switch loop involved. Check the wire colors at the switch.

You will need to install some sort of fan rated box to support your fan. The type would be determined on where the framing is located in relationship to where you want to mount the fan. There are styles with a spreader bar for between the joists and ones that screw to the side or bottom of a joist.

For cutting the larger hole you could use a Roto-zip tool with a carbide bit to cut the plaster and then use a wood bit for the lath. A carbide holesaw would work on other plaster styles.
 
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Old 10-05-09, 09:54 AM
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The fan needs to be mounted to a ceiling fan junction box.


It is inserted from below with through a hole the size of the Jbox.

You probably have a switch loop. Open the switch box. Do you have a single cable with two wires plus ground? You have a switch loop. You need to use a test light or analog multimeter to find out which cable is hot at the light.
 
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Old 10-05-09, 10:01 AM
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I have other office fixtures in this home. If I could get behind those and see how they were wired (all are wired in the same fashion), should the ceiling fan connect to the power grid the same as the office fixture? Also, since the office fixture has two whites and two blacks but my ceiling fan has one of each, can I just consolidate wires of the same type (i.e., assume that the multiple wires behave the same as the single fan wire) or will that run me into trouble.
 
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Old 10-05-09, 10:06 AM
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Originally Posted by ray2047 View Post
You probably have a switch loop.
The cable has a hot, receive, and ground.

What would the switch loop look like behind the switch?
 
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Old 10-05-09, 10:57 AM
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What would the switch loop look like behind the switch
As stated before one cable with two wires plus ground.
The cable has a hot, receive, and ground
Do you mean neutral?

 

Last edited by ray2047; 10-05-09 at 11:26 AM.
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Old 10-05-09, 11:05 AM
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I understand now, sorry for misreading. So basically, I just need to find all the hot wires and attach them to fan black, all the neutral and attach them to fan white, and connect the grounds.

This is why I never studied electrical engineering in my college days...
 
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Old 10-05-09, 12:01 PM
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Originally Posted by pcboss View Post
Is this in a commercial occupancy? If so for liability reasons you should hire someone properly licensed and insured to do this work.
This is a residential property that was formerly owned and used by a bank as office space.
 
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Old 10-05-09, 12:58 PM
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Originally Posted by MasonicAero View Post
I understand now, sorry for misreading. So basically, I just need to find all the hot wires and attach them to fan black, all the neutral and attach them to fan white, and connect the grounds.

This is why I never studied electrical engineering in my college days...
Not if it is a switch loop. Please look at the diagram again.

Neutral from power in (the hot cable) goes to the fan.

Black of power in goes to the white of the cable to the switch.

Black of the cable from the switch goes to the black, and if present, blue of the fan.

Of course you really haven't told us what wiring you have in the switch box so I'm guessing still.

All grounds are connected and if the Jboxes are metal are also pigtailed to the Jbox.

The white wire of the cable to the switch should re-identified with another color such as black or red or any color except green using tape or marker pen or paint.

Actual hook up can vary in color choices in some cases but for simplicity they are not included here.
 
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Old 10-06-09, 06:46 AM
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Cool Fixed!!!


It was a back-door switch. Here is a resolved diagram (like my original one that I opened the thread with) and a simple wire diagram.


Each color represents a wire-nut. Note which wires are connected below.


Thanks everyone for your help. Hope this can help someone else with the same issue. Just incase anyone is wondering, the neutral wire from the switch was originally not marked at all (hence my confusion at what this wire came from or went to), but I did stripe it black and white to designate it a "hot" wire from the switch.

Thanks again!
 
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Old 10-06-09, 06:56 AM
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The white wire from the switch should have been the constant hot, not the switched hot as in the way it was wired. This is clearly spelled out in the NEC in 200.7. It is a violation the way it is wired now.
 
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Old 10-06-09, 07:31 AM
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Why is this a violation? I thought 200.7 was just saying that "If a conductor with insulation that is white or gray or that has three continuous white stripes is used for other than a grounded conductor, the insulation must be reidentified at its termination and at each location where the conductor is visible and accessible."

The switch wires are redefined where they are connected into the light. I mean, the wiring is sound because it is just a power-at-the-light, single pole system. Is it a matter of wire labelling that makes it a violation?
 
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Old 10-06-09, 07:34 AM
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See 200.7(C)(2). The remarked white must be used as the supply to the switch.
 
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Old 10-06-09, 07:52 AM
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Ok, I thought I had read somewhere that NEC's didn't explicitly state receive-and-send roles for white wires on switches... just that they "had to be marked as hot". I'll fix that this evening. Luckily I just did the one fixture and waited till I knew what I was doing to do the others.
 
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Old 10-06-09, 08:00 AM
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In previous editions of the NEC it was not required to re-identify the white when used in a switch loop. Doing it the way you did you end up with both a white hot and a white neutral at the fixture.
 
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Old 10-06-09, 08:15 AM
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So in the world of electrical wiring, there is NO distinction between white wires and marked white wires? That is what I did, so I have a white going into the fan and a "blacked-out" white going in as "hot" to the fan.

EDIT: In other words, I understand if the "violation" is defined where my breaker power enters the black wire to the switch and exits the white wire FROM the switch, but if the "violation" is that there are two visually white wires entering the fan, then I am asking if "blacking out" (electrical tape or marker) the "hot" white wire exiting the switch and entering the fan makes it compliant.
 
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