difference between FMC and FMT???

[Energize]

Based on '05 NEC.

What is the difference between Flexible Metal Conduit (Article 348) and Flexible metal Tubing ( Atricle 360)?

I read their respective definitions, and other than FMT being liquidtight, I am wondering how I can see the difference with the naked eye.

The reason I am asking is that FMT is limited to 6 ft. or less in length, while there is no limit to FMC. If I cannot see the difference, how do I determine the difference? What else do I need to be looking for to determine which material I am working with?

Thanks in advance for your help -

 

[sgunsel]

Odd, I was just about to post the same question. Obviously I din't know either.

 

[crossman]

FMC is a spiral and is not liquidtight. FMT is a solid but flexible metallic tube and is liquidtight.

 

[Guinness]

Here's a link to an old posting

What is Flexible Metal Tubing - Article 360

http://www.mikeholt.com/mojonewsarc...lexible-Metal-Tubing-Article-360~20041108.php

 

[Energize]

Thank you for all the responses, but now I am more confused.

Why the limit of 6 ft on the FMT and not on the FMC?

Any Ideas?

Thanks -

 

[M. D.]

Thank you for all the responses, but now I am more confused.

Why the limit of 6 ft on the FMT and not on the FMC?

Any Ideas?

Thanks -

I would guess ,..that whatever reason is ,.. it has to do with the 40% less weight ...

 

[76nemo]

I thought the 6' rule was for EGC purpose. Am I wrong?

 

[M. D.]

360.12 Uses not permitted
(6) in lengths over 6'

 

[76nemo]

I was referring to 250.118 (5) C. Does this not state that the two can be used as a EGC if they don't exceed 6'?

250.118 states that "run with or enclosing......"

Do I have this wrong:-?

 

[don_resqcapt19]

76,
The rule in 250.118 has nothing to do with the rule in 360.12 that limits the use of flexible metal conduit to lengths of 6' or less.

 

[chris kennedy]

76,
The rule in 250.118 has nothing to do with the rule in 360.12 that limits the use of flexible metal conduit to lengths of 6' or less.

Typo...and you only have 7 mins to fix it. Oh yeah, your a Mod, take your time.

 

[russ]

FMT is used for fixture whips in environmental air spaces, that we used to call "plenum ceilings". It's the only fixture whip allowed in such ceilings in Chicago.
Most of the time the whips are manufactured and are shipped with the connectors and wire installed. I'm not sure where else it's used.
There should be some place I imagine.

 

[iwire]

FMT is used for fixture whips in environmental air spaces, that we used to call "plenum ceilings". It's the only fixture whip allowed in such ceilings in Chicago.

We use MC, or AC or FMC for that, why would FMT be needed? :smile:

 

[don_resqcapt19]

Bob,
Those cables and FMC have a spiral wrapped jacket and are not as smoke tight as FMT. I believe that the Chicago rules also require the use of compression couplings with EMT and plenum (no mounting holes, tighter knockouts)boxes in return air ceilings.