Nec

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relleston said:
what is the difference between FMC and FMT? how can I see a picture of the didderence?
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FMC, flexible metal conduit, commonly called Greenfield, is basically the same metal jacketing as Type AC or MC cable, but without conductors. It is available in both steel and aluminum jacketing, and I believe can go up to 4" in diameter.

FMC_Flexible_Metal_Conduit_UL_1_Standard.jpg


It is not permitted in wet locations or where subject to physical damage. Reference Article 348.



FMT, flexible metal tubing, is kind of cheap looking stuff, but is similar in look to FMC. The thickness of the jacketing of FMT is much thinner, but the circular rings that comprise it are much tighter. This makes it very lightweight. FMT, also called PlenFlex, is used often in plenums and other potentially combustible areas due to it being smoke-tight and liquid-tight (though it is not permitted in hazardous locations). It is not permitted where subject to physical damage. The NEC does not mention wet locations, though I'm pretty sure that FMT is galvanized for protection from corrosion, so you probably won't have a problem with this application.

PF.gif


Reference Article 360.



Boy, that is about the driest post I think I ever made. Hope it was informative. By the way, the title of this thread is not very helpful.
 
The Lordofpi gave a good explanation. I would add that FMC is permitted in wet locations when used with conductors approved for wet locations and installed to prevent liquids from entering the enclosures connected to the FMC. And although I haven't worked with FMT in years I believe that it's made from a corrugated liquid tight aluminum tube unlike FMC which is wound from a metal strip.
 
lordofpi said:
It is not permitted in wet locations
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Actually it was OK in wet locations under the 2005 NEC and maybe the 2002.

Check out 2005 348.12(1)

I believe that is changing in the 2008 NEC.
 
WE use FMT in "plenum" ceilings in Chicago for the whips to fixtures. We have all kinds of crazy requirements for environmental air spaces.
 
russ said:
WE use GMT in "plenum" ceilings in Chicago for the whips to fixtures. We have all kinds of crazy requirements for environmental air spaces.
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Actually that was the one time I used the stuff. The fixtures were delivered and noted something to the affect of 'Approved for Use in the City of Chicago'
 
iwire said:
Actually it was OK in wet locations under the 2005 NEC and maybe the 2002.

Check out 2005 348.12(1)

I believe that is changing in the 2008 NEC.
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Yes, sorry for not specifying. All references were with respect to the 2008 NEC.

2008 NEC said:
348.12 Uses Not Permitted. FMC shall not be used in the following:
(1) In wet locations
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lordofpi said:
Yes, sorry for not specifying. All references were with respect to the 2008 NEC.
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In my opinion it is to early to be using the 2008 for answers here, no area has yet adopted it. It will be months and in some cases years before it is adopted.

I happen to live in an area where we will use the 2008 Jan 1st (at least going by past history) that is unusual, it seems the majority of areas wait some time before adoption. :smile:
 
I guess that is true, Bob. Even the states that surely will adopt '08, 98% won't be immediate. I generally prefer to look forward instead of learning a rule that is about to be obsolete or somehow changed. However, I will keep this in mind.
 
John, the 08 NEC will not be adopted in NC until July of 08.

Roger
 
electricman2 said:
The jurisdictions where I work will adopt the 08 code effective Jan 1. This has been true in 99,02, and 05.
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Are you saying that your area of NC will adopt the 2008NEC before the state does?

As Roger has said it won't be till June or July 08 that it will be adopted with some amendments.
 
electricman2 said:
Roger, I was told at the inspections dept that the 08 will be enforced as of Jan 1. Maybe they are misinformed.
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Over my years working for Municipalities once a new code is adopted the enforcement of that new code is for new permits issued at and after the adopted date. The dept. can't just run out and enforce a newly adopted code on outstanding permits previously issued prior to the newly adopted version.
 
electricman2 said:
Roger, I was told at the inspections dept that the 08 will be enforced as of Jan 1. Maybe they are misinformed.
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John, I would say they are misinformed.

Roger
 
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