# Fan Box in Concrete Plank



## flyingspade (Apr 9, 2009)

I am having some problems trying to figure out what the best route for installation of a ceiling fan.

Scenario: 
- Pre-cast Concrete Plank - Hollow Core
- Ceiling Fan supported off Concrete Plank
- No Surface Mount Boxes / conduit

Proposed Solution:
- MC cable fed through Hollow Core 
- Electrical Box - Core Drilled and Chipped to support fan listed pancake box
- MC cable to attach to back of box - 1" Hole to Pre-cast hollow portion
- Toggle Bolts - Supporting of Box

My question is, are there other products out there I have not considered? I am worried of using old work ceiling fan boxes, as I would be unable to secure these inside the hollow core. Any other suggestions?


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## randas (Dec 14, 2008)

You should just be able to attach the pan box to the surface of the concrete and the canopy will cover it.


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## bobelectric (Feb 24, 2007)

Do they make a fan-rated ceiling pan?


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## flyingspade (Apr 9, 2009)

Randas - Have you run into a ceiling fan product that wouldn't accept this? Only information I have about the fan is that it's a Casa Vieja 52" Fan. I personally have not installed many ceiling fans in my career, so any information would be appreicated. 

Bob - Sure do, RACO 295-1.


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## Celtic (Nov 19, 2007)

bobelectric said:


> Do they make a fan-rated ceiling pan?



Mount the back plate to the deck....right through the pancake....doesn't need to be fan rated if it isn't used for support.


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## MrsElectric (Aug 12, 2011)

http://www.lowes.com/pd_74211-427-295_4294722500__?productId=3129641&Ns=p_product_avg_rating|1

fan rated pancake, use them all the time


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## drumnut08 (Sep 23, 2012)

flyingspade said:


> I am having some problems trying to figure out what the best route for installation of a ceiling fan.
> 
> Scenario:
> - Pre-cast Concrete Plank - Hollow Core
> ...


Core drilling and chipping the precast in order to make a 1/2" deep fan rated pancake box flush seems like a lot of unnecessary work and you'll have a harder time securing that box now than if you left the precast alone . The canopy may not sit 100% tight to the precast , unless its a large based hugger style fan ? I agree with fishing the precast plank with mc , but use a small push in style mc connector at the box end to minimize the size hole you need to make . Bigger hole for the connector = less usable surface area to fasten your box .


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## flyingspade (Apr 9, 2009)

Drumnut08 – I do agree that the chipping and installation of the pancake box in the concrete plank is excessive. The customer has boldly in their bid documents to *not* have *any* exposed boxes. My largest concern is supporting of the box after drilling. I fear my employees would make a couple of mistakes, and cause a large expense to repair the concrete plank.

I hope everyone can agree on the following items in this instance:
-	Core drilling of concrete and chipping will be very time consuming. 
-	Installation of box anchors (short steel drop-in) could cause weak points in concrete and bust out. In situations of concrete blow-out, I would have to use toggle bolts. However, toggle bolts would still require a large hole for the wings to open, and I’m worried that it would be hard to secure the box to the concrete.
-	Ideal situation is to have the pre-cast concrete supplier to plan and provide recessed holes for the box and MC cable.

I figured some people would have ran across a situation like this in the past. It does not have to relate directly to a fan box, but any box that has to be recessed in concrete plank. If there is a product out there that would help in any way?


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## MDShunk (Jan 7, 2007)

Flyingspade... you may be under the impression that fan must be supported from the box. This is plainly untrue. The fan may also be supported from the structure. 

I do a ton of work for a manufacturer of concrete plank (spandeck) who also builds the structures. For fans, the normal method is to core a 3-1/4" hole and drill two 1/4" holes at 3 o'clock and 9 o'clock 1" from the edge of this cored hole. Cut a piece of 1/4" x 1" flat steel stock 12" long. Drill and tap four 1/4-20 holes in that strap. Two to mount the 3-1/4" pancake box, and two to align with the 1/4" holes you drilled in the concrete to mount the fan bracket to. Slip that bar up inside the spandeck, mount the box, then you mount the fan bracket on the face of all of that, using 1/4-20 bolts through the concrete and catch the tapped holes in that flat stock strap you have up inside.


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## Toronto Sparky (Apr 12, 2009)

I try to use the hugger type fans (with the big base) so they can be supported to the structure , not the box..
There's something about supporting a ceiling fan with two 8-32 screws that never sat well with me..


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## MDShunk (Jan 7, 2007)

Toronto Sparky said:


> I try to use the hugger type fans (with the big base) so they can be supported to the structure , not the box..
> There's something about supporting a ceiling fan with two 8-32 screws that never sat well with me..


I try not to get involved with fan selection whenever possible. :thumbsup:

But I agree, the hugger solves this mounting issue right off the bat. Mount any box, then mount the whole works over top of it. In the 80's, most fans were huggers. In 2012, few are.


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## RePhase277 (Feb 5, 2008)

Use an octagon blank with a 1/2" KO in it, secured to the concrete with a couple of tap cons. Then secure the fan bracket staright to the concrete with drive pins or whatever.

This gives you a place terminate the cable. Let the flaming begin...:thumbup:


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## Toronto Sparky (Apr 12, 2009)

I hate drive pins...  Too hard to remove in the future especially when overhead.. Not a big fan of tap cons ether, because I've seen them fall out with vibration or rust in wet conditions..

Add easy anchor and anything installed with explosive activated tool to my don't like fastener list..


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## RePhase277 (Feb 5, 2008)

Toronto Sparky said:


> I hate drive pins...  Too hard to remove in the future especially when overhead.. Not a big fan of tap cons ether, because I've seen them fall out with vibration or rust in wet conditions..
> 
> Add easy anchor and anything installed with explosive activated tool to my don't like fastener list..


Just admit it... you don't like attaching stuff to concrete, do you?


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## Toronto Sparky (Apr 12, 2009)

InPhase277 said:


> Just admit it... you don't like attaching stuff to concrete, do you?


Rawl plugs or tamp ins with threaded rods.. (bolts are often too short to lock the wedge in)

These are cool to but only if holes are drilled deep enough to bury them when no longer needed.


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