PLFA Cables Support Requirements

[msimms]

We are running PLFA cables inside a facility, and have come across a question regarding conduit as support means. Per the code, PLFA cable cannot be run on the outside of conduit (760.143), however nothing is stated for NPLFA cable. Also, it seems to allow PLFA cable to run exposed, but only on ceilings or sidewalls and out of harms way (760.24), and supported with zip-ties.

Anybody know why PLFA cables cannot be run on conduit even if its shielded, yet can be run on building structure supports? Can anyone confirm (or have experience) regarding the allowance of NPLFA cable run on the outside of conduit? I know I've seen it.

 

[cowboyjwc]

300.11(B)

 

[pete m.]

300.11(B)

John,

Maybe I missed it but I couldn't find where 300.11(B) is applicable.

760.3 Other Articles.Circuits and equipment shall comply with 760.3(A) through (G). Only those sections of Article 300 referenced in this article shall apply to fire alarm systems.

Pete

 

[msimms]

yeah, unfortunately it didnt really answer my question. the issue i am trying to understand, is why NPLFA is allowed strapped to conduit, and not PLFA (see 760.143 that explicitly disallows this) and yet we can supposedly strap the PLFA wire to building support systems.

 

[pete m.]

yeah, unfortunately it didnt really answer my question. the issue i am trying to understand, is why NPLFA is allowed strapped to conduit, and not PLFA (see 760.143 that explicitly disallows this) and yet we can supposedly strap the PLFA wire to building support systems.

NPLFA, as I am reading it, is not allowed to be supported by conduit either.

760.46 NPLFA Circuit Wiring.Installation of non–power-limited fire alarm circuits shall be in accordance with 110.3(B), 300.7, 300.11, 300.15, 300.17, and other appropriate articles of Chapter 3.

300.11 Securing and Supporting.
B) Raceways Used as Means of Support. Raceways shall be used only as a means of support for other raceways, cables, or nonelectrical equipment under any of the following conditions:
(1) Where the raceway or means of support is identified for the purpose
(2) Where the raceway contains power supply conductors for electrically controlled equipment and is used to support Class 2 circuit conductors or cables that are solely for the purpose of connection to the equipment control circuits
(3) Where the raceway is used to support boxes or conduit bodies in accordance with 314.23 or to support luminaires in accordance with 410.36(E)

Pete

 

[cowboyjwc]

NPLFA, as I am reading it, is not allowed to be supported by conduit either.

760.46 NPLFA Circuit Wiring.Installation of non?power-limited fire alarm circuits shall be in accordance with 110.3(B), 300.7, 300.11, 300.15, 300.17, and other appropriate articles of Chapter 3.

300.11 Securing and Supporting.
B) Raceways Used as Means of Support. Raceways shall be used only as a means of support for other raceways, cables, or nonelectrical equipment under any of the following conditions:
(1) Where the raceway or means of support is identified for the purpose
(2) Where the raceway contains power supply conductors for electrically controlled equipment and is used to support Class 2 circuit conductors or cables that are solely for the purpose of connection to the equipment control circuits
(3) Where the raceway is used to support boxes or conduit bodies in accordance with 314.23 or to support luminaires in accordance with 410.36(E)

Pete

See all ya gotta do is read.:happyyes:

 

[pete m.]

See all ya gotta do is read.:happyyes:

I have no trouble reading... it's usually just the comprehension thing that throws me.:blink:

Pete

 

[msimms]

I did read that section, but like pete mentioned, it may come down to the comprehension portion. the way i read 300.11(B)(1), it seemed to indicate that as long as its identified as means of support, then it could be used as support means. we run predominantly RGS which is obviously very strong, and not to mention i've seen numerous older style residences with fire alarm control cable strapped to rgs pipe or other types, with tie-straps. while the articles on PLFA cable explicitly states that it cannot be placed on pipe (760.143), there are zero sections regarding NPLFA. so based on your feedback, i'm supposing in this instance, as you two have stated, that I cannot strap any fire alarm cable to any conduit pretty much, that I should find support rods, tray or support to the building structure, and out of any path that could potentially harm the cable, agreed?

 

[cowboyjwc]

I did read that section, but like pete mentioned, it may come down to the comprehension portion. the way i read 300.11(B)(1), it seemed to indicate that as long as its identified as means of support, then it could be used as support means. we run predominantly RGS which is obviously very strong, and not to mention i've seen numerous older style residences with fire alarm control cable strapped to rgs pipe or other types, with tie-straps. while the articles on PLFA cable explicitly states that it cannot be placed on pipe (760.143), there are zero sections regarding NPLFA. so based on your feedback, i'm supposing in this instance, as you two have stated, that I cannot strap any fire alarm cable to any conduit pretty much, that I should find support rods, tray or support to the building structure, and out of any path that could potentially harm the cable, agreed?

agreed. Look at 300.11(C) you can't even support a cable from another cable. Think of it this way, say that you ran an emt conduit above a t-bar ceiling and then the low voltage guy comes out and uses your conduit as his support. Now you come back and reroute or remove you emt for whatever reason, now his cable, which is required to be supported, isn't. Now who's responsible to secure it? You or the low voltage guy? Remember he already secured it once, you're the one who removed it.

 

[msimms]

sounds good; yeah i would never strap one cable to another, but makes sense about potential removal of conduit (demo).

thanks guys for the help.