coduit/cable over bar joist under roof decking

[pinkmenace]

hello all,my books not in front of me but i looked it up and found the article stating that except for imc or rigid conduit you must maintain 1.5 inch clearance from the lowest part of the roof decking.Now comes the interpretation,is it 1.5 inchs from the lowest part even if your in the upper portion of the decking, or am i interpreting wrong.

 

[PEDRO ESCOVILLA]

that would be 1.5 inches from the lowest point (if you had "channel drain, or "ribbed decking" i just set a rack (kindorf/unistrut/etc) to the deck and roll,that gives me the clearance and a good way to run. section 300.4 (E) 2005 nec thats a newish one new to 2005 any way

 

[infinity]

The lowest part of the roof decking.

300.4(E) Cables and Raceways Installed Under Roof Decking. A cable- or raceway-type wiring method, installed in exposed or concealed locations under metal-corrugated sheet roof decking, shall be installed and supported so the nearest outside surface of the cable or raceway is not less than 38 mm (1? in.) from the nearest surface of the roof decking.

 

[tkb]

I was just discussing this with another guy at work and was questioned on if communication cables are restricted from this as well.

The way I read it is, that communication cables are allowed in the deck webbing and are not restricted by 300.4(E) since communication cables are a Chapter 8 installation, but low voltage cables are restricted.

 

[don_resqcapt19]

Rob,
That would be from the 2008 code and the wording was changed for 2011 because 2008 did not really require the cable to be 1.5" below the lowest surface...it only had to be 1.5" below the nearest surface.

(E) Cables, Raceways, or Boxes Installed in or Under Roof Decking. A cable, raceway, or box, installed in exposed or concealed locations under metal-corrugated sheet
roof decking, shall be installed and supported so there is not less than 38 mm (11⁄2 in.) measured from the lowest surface of the roof decking to the top of the cable, raceway,
or box. A cable, raceway, or box shall not be installed in concealed locations in metal-corrugated, sheet decking?type roof.

 

[infinity]

Rob,
That would be from the 2008 code and the wording was changed for 2011 because 2008 did not really require the cable to be 1.5" below the lowest surface...it only had to be 1.5" below the nearest surface.

Was that one of your proposals?

Yes, we're still on the 2008 so that's what I used. The 2011 added something about boxes requiring the 1.5" as well.

 

[don_resqcapt19]

Was that one of your proposals?

Yes, we're still on the 2008 so that's what I used. The 2011 added something about boxes requiring the 1.5" as well.

It was not one of mine.