Flexible Cords Below Raised Floor

[publicgood]

I ran across this Mike Holt image showing flexible cords being plugged in below a raised floor and above a drop ceiling. It notes this to be okay for raised floors, but not drop ceilings. The reference is to 400.8(5) with emphasis on the definition for "concealed."

Is the assumption here that the raised floor has a protective grommet and the drop ceiling is just a hole through a ceiling tile? Would it be different if the tile was just lifted and cord snaked through (leaving the tile slightly open)? I feel like I've seen a graphic for ceiling mounted projectors not being allowed to have their receptacle above the ceiling.

Note: Often raised floor tiles are screwed down, rendering the underfloor not readily accessible.

Looking to hear thoughts on this subject and also how it may relate to 400.8(2). I would also highlight that 400.7 does not give below a raised floor or above a dropped ceiling as a permitted use.



http://www.ecmweb.com/code-basics/cords-and-fixture-wires

http://www.ecmweb.com/sites/ecmweb.com/files/uploads/2004/04/404ecm17fig1.jpg

 

[ron]

I think the graphic is incomplete. I suspect his allowance of cords below the floor is related to 300.22(D) and the assumption that the pre-requisites of 645 will be followed allowing the leniencies permitted by 645 (relaxed rules if chosen to follow with the pre-requisites).

Sections in 645 amends 400 and other Chapter 1-4 sections that are identified.

 

[dkidd]

see http://forums.mikeholt.com/showthread.php?t=160934

The graphic is old. I am pretty sure that Mike has said that appliance cords fall under UL. NEC applies to fixed wiring methods.

 

[petersonra]

see http://forums.mikeholt.com/showthread.php?t=160934

The graphic is old. I am pretty sure that Mike has said that appliance cords fall under UL. NEC applies to fixed wiring methods.

I have never quite understood why electricians have tried to make utilization equipment meet the code. With a few exceptions, they just are not covered by the code.

90.2 Scope.
(A) Covered. This Code covers the installation of electrical
conductors, equipment, and raceways; signaling and communications
conductors, equipment, and raceways; and optical
fiber cables and raceways for the following:

It is hard for me to see how a table lamp is part of an "installation".

 

[zbang]

Note: Often raised floor tiles are screwed down, rendering the underfloor not readily accessible.

Your mileage may vary- I hardly ever find screwed-down floor tiles, and then it's only around specific large pieces of equipment, like air conditioners. Must be a local thing.

 

[jumper]

Your mileage may vary- I hardly ever find screwed-down floor tiles, and then it's only around specific large pieces of equipment, like air conditioners. Must be a local thing.

Me too and even if screwed down, that is okay. NEC says accessible not readily accessible.

 

[publicgood]

Your mileage may vary- I hardly ever find screwed-down floor tiles, and then it's only around specific large pieces of equipment, like air conditioners. Must be a local thing.

In data center applications I don't see floor tiles screwed down, but in say an office space with carpet on raised floor I see this frequently.

 

[publicgood]

I think the graphic is incomplete. I suspect his allowance of cords below the floor is related to 300.22(D) and the assumption that the pre-requisites of 645 will be followed allowing the leniencies permitted by 645 (relaxed rules if chosen to follow with the pre-requisites).

Sections in 645 amends 400 and other Chapter 1-4 sections that are identified.

Exactly what I was hoping to hear. My thought also: 645 is required for the allowance of plugging in below raised access floor.

 

[publicgood]

see http://forums.mikeholt.com/showthread.php?t=160934

The graphic is old. I am pretty sure that Mike has said that appliance cords fall under UL. NEC applies to fixed wiring methods.

Thanks for the link to the other thread - insightful. I am on the fence about the note of UL.

No matter, I found it interesting that no one brought up the point about appliance cords or flexible cords actually being the local disconnecting means.

 

[jumper]

Thanks for the link to the other thread - insightful. I am on the fence about the note of UL.

The inspectors I have talked to about this are saying they disagree and say a cord is a cord and will not allow it.

 

[dkidd]

That graphic was part of the article

http://www.ecmweb.com/code-basics/flexible-cords-cables-and-fixture-wire

Scan down to the Heading "Banned". The graphics are no longer on the website, but I have a pdf I printed and saved.

It says

You can install receptacles above suspended or dropped
ceilings, but you can't install flexible cords up there to plug into
them. So what's the point of installing the receptacle? The
receptacle can supply power for portable lights and tools, but that
receptacle can't be used to supply cord- and plug-connected
equipment fastened in place, such as a permanently mounted
projector.

 

[petersonra]

just because it says so does not make it true, although a permanent installation of a projector is close to being a part of the installation, much more than a table lamp is.

 

[jumper]

That graphic was part of the article

http://www.ecmweb.com/code-basics/flexible-cords-cables-and-fixture-wire

Scan down to the Heading "Banned". The graphics are no longer on the website, but I have a pdf I printed and saved.

It says

You can install receptacles above suspended or dropped
ceilings, but you can't install flexible cords up there to plug into
them. So what's the point of installing the receptacle? The
receptacle can supply power for portable lights and tools, but that
receptacle can't be used to supply cord- and plug-connected
equipment fastened in place, such as a permanently mounted
projector.

Not totally uncommon for receptacles to be installed near HVAC units for servicing.