ECN Forum
Posted By: Bravo Wiring Methods-Art 300.22 (B) - 08/16/11 03:20 PM

This thread is an addition to a thread I posted (Wiring Methods on 8/04.

Does anyone know if LFMC (Type ZHUA) available from Anamet Electrical is permitted to use in a plenum enviromental area per 300.22?

It has a zinc core with a pvc jacket that is low smoke, zero halogen TPU jacket that resists heat, oil and chemical breakdown. The sales rep said it conforms to Art 300.22 and it references NEC on the cut sheet.

I will use this cable as a pwr cord that will suspend from a hung ceiling with a hubbell connector on the end. The other end of the cable will go above the clg approx 4ft to a wiring trough. Splice connections in the trough and then EMT to panel board.

Are there any white paper articles that discuss if this type LFMC is allowed per NEC?

Sorry for the lengthy thread and thank you in advance.

question is

Posted By: renosteinke Re: Wiring Methods-Art 300.22 (B) - 08/16/11 03:47 PM
Are you trying to make a substitute for a flexible cord above a drop ceiling?

I am not aware of any cord connectors ("plugs") that have been evaluated for use with LFMC. Let me expand on that: I have personally done the strain relief tests on such assemblies, and they failed miserably.

I do not see any code section that specifically addresses the use of LFMC above ceilings. For that matter, I do not see where pipe is specifically discussed for use above ceilings.

LFMC is permitted where 'flexibility is required.' Do you require flexibility?

LFMC is not allowed where 'subject to damage.' Does passing it through the ceiling make it subject to damage?
Posted By: Bravo Re: Wiring Methods-Art 300.22 (B) - 08/16/11 04:24 PM
I do require flexibility. The flexible cord/plug will be used to mate with connectors for testing.

This can be solved if we extend the trough or j-box below the clg and eliminate the need for plenum rated cord and use just type SOOW pwr coord.

THe LFMC will pass thru a brush guard that is flush with the clg tile so it will not be subject to damage.
Posted By: renosteinke Re: Wiring Methods-Art 300.22 (B) - 08/16/11 09:47 PM
I am not aware of the term 'plenum rated' ever being applied to LFMC.

Nor is that rating necessarily relevant. You have not described a plenum, you have described a suspended ceiling. Most suspended ceilings are not plenums, and the use of flexible cords is still proscribed.

We recently had here a lively discussion regarding the use of flexible cords within a raceway. That, perhaps, is what you are describing here. It's certainly the only way I can see to somehow transition from LFMC to flexible cord, unless you want to mount a box directly to the ceiling grid.

Naturally, you have to attach such a box to the grid- yet you are not allowed to 'support' the box with the grid. go figure.

I can think of all manner of ways to do what you propose to do, yet I cannot find any that is absoluttely compliant with the latest code editions- even though all manner of listed gizmos are made for mounting things to the grid! For example, the 'cord in the pipe' thread led to some lively discussion.
Posted By: HotLine1 Re: Wiring Methods-Art 300.22 (B) - 08/17/11 02:50 AM

Some verbage from '11 NEC Art 350.30....

"Exception No. 4: Lengths not exceeding 1.8 m (6 ft) from
the last point where the raceway is securely fastened for
connections within an accessible ceiling to luminaire(s) or
other equipment."

Note the words 'accessible ceiling'....

From '11 NEC, Article 100 definitions.....

'Plenum. A compartment or chamber to which one or more
air ducts are connected and that forms part of the air distribution

This term is widely used as the cavity above a 'drop ceiling' that is used for return airflow, as opposed to a HVAC system with ducted return air.

Hence items like 'plenum rated Cat5/6', etc.

I see no mention of LFMC within Article 300.22.
Posted By: HotLine1 Re: Wiring Methods-Art 300.22 (B) - 08/17/11 03:02 AM

I see the reference to 300.22 within the mfg literature from your link. I went back to 300.22 ('11) and read twice, and I do not see any reference to LFMC.

Perhaps I'm missing what the sales rep was alluding to ?

© ECN Electrical Forums