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#92113 - 02/26/05 02:59 PM Receptacles under raised floors  
Elzappr  Offline
Member
Joined: Dec 2001
Posts: 270
Oregon
Can receptacle outlets be placed under raised floors for power to office equipment?


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#92114 - 02/26/05 05:15 PM Re: Receptacles under raised floors  
George Little  Offline
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Joined: Jan 2004
Posts: 1,489
Michigan USA
I would say probably it's red tag time. I say that because a receptacle under the floor would obviously leed to a cord under the floor and now we have trouble with 400.8(5). The exception could be in a computer room, raised floor.


George Little

#92115 - 02/26/05 08:03 PM Re: Receptacles under raised floors  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,057
Estero,Fl,usa
Even under a computer room raised floor you need plenum rated power cords. There are always going to be receptacles but they will be IEC309s or Russell Stolls, not the usual NEMA 5-15


Greg Fretwell

#92116 - 02/26/05 08:36 PM Re: Receptacles under raised floors  
Ron  Offline
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Joined: Mar 2002
Posts: 582
White Plains, NY
Since a flexible cord can't be below the raised floor, there is no need for a receptacle.
If you are 645 compliant, then its ok if the cord is rated as 'DP'.
Why not place a floor box in the raised floor tile, then all is ok.


Ron

#92117 - 02/26/05 10:33 PM Re: Receptacles under raised floors  
Elzappr  Offline
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Joined: Dec 2001
Posts: 270
Oregon
You all have confirmed my suspicions. What I am dealing with is a 5 story building with cords plugged in regular duplex receptacles under the raised floors. The cords are actually 20' long plug strips. they poke up through bushed holes in the concrete floor tiles. This is not a computer room nor server room situation, just a general office space.
As far as I know, this set-up has never been allowed by code. Right?


#92118 - 02/26/05 10:55 PM Re: Receptacles under raised floors  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,057
Estero,Fl,usa
That is not legal, nor is simply converting old computer room space to office space, retaining the raised floor for a "convienient" wiring bay. When computers stopped being an acre of boxes and became a rack they had lots of raised floor real estate. It ends up being an office but they still use the floor for a plenum and they lose all the breaks they got in 645.


Greg Fretwell

#92119 - 02/27/05 01:39 AM Re: Receptacles under raised floors  
George Little  Offline
Member
Joined: Jan 2004
Posts: 1,489
Michigan USA
Greg, are you sure about this?
Quote
Even under a computer room raised floor you need plenum rated power cords. There are always going to be receptacles but they will be IEC309s or Russell Stolls, not the usual NEMA 5-15

I thought that the cord and the wiring method to the receptacle were the only issues. please educate me.


George Little

#92120 - 02/27/05 01:59 AM Re: Receptacles under raised floors  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,057
Estero,Fl,usa
Actually Ron hit the code issue. (listed "DP" cable)
The reason you don't see regular receptacles under the floor is you don't want to crash the system because someone yanked the wrong cable and pulls out a plug to a critical box.


Greg Fretwell

#92121 - 02/27/05 02:47 AM Re: Receptacles under raised floors  
George  Offline
Member
Joined: Feb 2002
Posts: 375
I don't wish to start a fight over the issue, but I don't think it is as clear cut as it could be ...

I can certainly run a standard cord under a table. I can carpet my floor with tables. I can place the recept below table ehight. I can walk on top of the tables and place my furniture on top of the tables.

I used the word "table" where most people would use the word "floor."


#92122 - 02/27/05 03:44 AM Re: Receptacles under raised floors  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,057
Estero,Fl,usa
I can call my pool a bathtub but that doesn't mean the AHJ will let me ignore 680.
If your AHJ decides your tables are really a floor you will have to follow the rules about penetrations.
Virtually all computer room floors are plenums, moving environmental air. That is why they have the rules about cable flamability.
There are also recognized office floor duct systems so we want to be sure what we are talking about here.


Greg Fretwell

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