2005 NEC 334.12 (A) (2)

[steveray]

I have an electrical contractor that has already installed NM cable (prior to issuance of his permit, long story) above a proposed suspended ceiling. They are now looking for a solution that does not involve "rip it all out". Exposed does not have a great definition in the NEC, they are proposing to cover everything with FSK (foil scrim craft) which I believe works as an ignition barrier, but I don't know if it then qualifies as "inaccessible" or not "exposed". I don't like the idea, and I think they should have just done it right the first time, but I am looking for some input on meeting the intent.

Thanks in advance for any insight or opinions!

Ray

 

[raider1]

Re: 2005 NEC 334.12 (A) (2)

Here is the definition of exposed as it applys to wiring methods in the NEC.

"Exposed (as applied to wiring methods). On or attached to the surface or behind panels designed to allow access."

IMHO even if they wrap the NM cable it would still be exposed.

Chris

 

[steveray]

Re: 2005 NEC 334.12 (A) (2)

Thanks for the reply Chris,

I am not talking about just wrapping the cable, but covering the entire ceiling(ceiling above the dropped ceiling that is) assembly(plumbing,wiring,framing) with FSK. If it is enclosed/covered with a membrane, is it then accessible/exposed. And at that point, what thickness of material needs to cover it to consider it so? I am not trying to solve their problem for them, but i do like to address all possibilities and answer as many questions that come up!

Thanx again!

 

[raider1]

Re: 2005 NEC 334.12 (A) (2)

If they completely separate the NM cable from the suspended ceiling area with a finish material with a 15 minute finish rating then you might be OK.

Chris

 

[steveray]

Re: 2005 NEC 334.12 (A) (2)

That is what I was thinkin! I don't like it, but I think I might have to approve it! I think next time he will probably run MC. Amazes me the amount of electricians arond here don't know the limits of NM cable. On his application under wire type he put RX, that was my first warning.

Thanx again!

 

[north star]

Re: 2005 NEC 334.12 (A) (2)

steveray,

We see incorrect NM installations all the time! By the time we get to inspect the wiring, its too late for the

"rip it all out" card. I would bet that the next time, that same electrician will once again run the NM where

he wants to. Until someone steps up and actually makes him run a compliant installation, he will keep on

doing what he can get by with ( i.e. - until it costs him money ), ...IMO!

 

[steveray]

Re: 2005 NEC 334.12 (A) (2)

North star,

It is going to cost him money, not as much as rip it all out, but he will still lose days of labor and some material. I think he is just primarily a residential electrician, just working a little outside of his comfort zone. He may still rip it out and run MC, but for now I am doing my due diligence, and figuring out what I can and cannot approve. That whole "exposed" definition and wording is just a little vague. I don't have any NEC commentary, and I was not an electrician by trade, so asking the experts here and in my neighboring municipalities is my best resource. We are all learning every day!

 

[Builder Bob]

Re: 2005 NEC 334.12 (A) (2)

Although not in the NEC, the IFGC states that an suspended ceiling system is still accessible by their definition due to easy removal of ACT panels and the amount of air transfer allowed by traditional ACT.

Suggest, removal of existing ceiling grid and replacing it with a fire rated ceiling assembly (medium or heavy duty ceiling grid with fire rated ceiling tiles) ---- What is the manufacture's suggestion for seam overlaps, coverage, etc. The Grease Hood Duct wrap is now required to be a double wrap to meet the testing criteria. Has this product been tested to U268 standards? Where is the ICC evaluation sheet on this product?

In other words, where is the testing agency certification and manufacture's installation guide for the "15" ignition barrier - A bake potato is covered by foil, but it still cooks the potato in an oven....Foil conducts heat, what is going to prevent the transfer of heat to combustibles thru this foil covering if no air space is provided to allow for thermal dissipation of said heat?

 

[steveray]

Re: 2005 NEC 334.12 (A) (2)

He hasn't submitted anything formally as of yet, but I will certainly be looking for documentation of whatever he submits. Even a fire rated ceiling is still "accesible", but by the letter of the code, it seems as though "covered" in any way is no longer "accessible"! Again, I don't like it and will argue, but I may have to approve it!