300.4 D overkill

[a.wayne3@verizon.net]

To those that wire block homes this will be informative,Last year the AHJ`S started requiring us to protect the nm cable where it crosses horizontal furring into truss areas with additional nail plates,so that the ceiling drywall can`t contact the nm in this area when installed ,citing 300.4 D.In addition to the nail plate that protects the NM where it crosses the furring they wanted additional nail plates in the area above the furring,if there was enough room to slide drywall into that area.What a pain but we complied.One nail plate horizontal on the furring and ond on a 45 to protect this area.Personally I saw a potentially hazardous installation.Well my fears turned out to be valid.One of the service crews called me and asked me to come by.The call was when ever the HO touched the SGD frame he got shocked.Long story short,The corner bead was energized as well as the foil backed vapor barrier.After removing the drywall over a 4 gang box I found this additional nail plate had been pressesd into the 14/3 for a Lanai fans constant hot.The nail plate had in turn been energized, the foil faced vapor barrier as well and the corner bead.A 3 year old child had been lit up as a result.I called the chief as well as the area inspector and informed them of what had transpired.For now no more additional nail plates. But I can`t help but think off all the homes that had this type of protection and how many more problems like this will come to bear.

 

[hurk27]

Re: 300.4 D overkill

We have the same problem in 1/2 in the ground basements the wall studs are 2x4's that line up with the outside wall. This leaves a ledge on top of the block wall so the framers will use a 2x2 horizontal to fir out the bottom half of the wall (block part) This leaves only 1.5" to run our N/M in so the inspectors have been requiring EMT to protect the wires. But where we have to transition to the upper part we have to get real close to the drywall because there is only a 2x8 plate on the top of the block and we have to nail plate it but I can See this happening too.

 

[a.wayne3@verizon.net]

Re: 300.4 D overkill

The use of 1/2 in. EMT came up also but with using furring the EMT is wider O.D. than furring ,that would place it outside the wall.Besides how is it bonded ???Unless you use 4 sq`s and run the EMT from that box to the truss/joist area`s.For now we went back to the 1 nail plate scenario,I am waiting for the next brainstorm to arrive :roll:

 

[iwire]

Re: 300.4 D overkill

Originally posted by a.wayne3@verizon.net:
The use of 1/2 in. EMT came up also but with using furring the EMT is wider O.D. than furring ,that would place it outside the wall.Besides how is it bonded ???

It does not have to be grounded.

250.86Exception No. 2: Short sections of metal enclosures or raceways used to provide support or protection of cable assemblies from physical damage shall not be required to be grounded.

 

[a.wayne3@verizon.net]

Re: 300.4 D overkill

Bob you are 100 % correct I didnt do my homework.But to use EMT would cause allot of problems when there is a 4,5 or 6 gang box.consider a 5 gang with 3 ways 4 ways and 3 wire ceiling fans.There wouldn`t be enough lumber left to mount drywall to after sleeving nm in EMT and it would still be out of the wall.How many of you have seen nm damaged by dry wall where it enters the truss/joist space,why fix what isn`t broken.As far as I am concerned this is taking a simple matter and turning it into a major problem.

 

[apauling]

Re: 300.4 D overkill

I think the obvious solution here (1&1/2" furred block walls) is buried in our traditional "after the framing" mentality.. If the wall is wired in emt before the framing is in, the carpenters can slam dunk the sheetrock nailers after the piping is done, and ergo no sheetrock nails or screws, no over picky inspectors, under safe electricians, nicked wires.

a connector must be used on the ends of pipe or flex, even if not connected to a box.

just an idea

paul

 

[hurk27]

Re: 300.4 D overkill

Paul

a connector must be used on the ends of pipe or flex, even if not connected to a box.

I think Arlington makes a slip over bushing for that use:

Arlington Insulating Bushings Press fit.


Here's what they sat there for:

Arlington's EMT Insulating Bushings protect cables from abrasion by EMT. For use wherever a fitting would otherwise not be required. Examples: Power, Cable TV, computer data lines, telephone/modem, audio/video cables, alarm systems, security systems - EMT is often used to protect cables where damage could occur in a house or building

[ July 20, 2004, 12:45 AM: Message edited by: hurk27 ]

 

[hurk27]

Re: 300.4 D overkill

Just a question: Can wire-mold be ran under sheetrock?