Resi question

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SiddMartin

Senior Member
Location
PA
I know in a basement you can not run RX under the joists, but if there is a drop ceiling, I believe it is allowed, but can't find the code to back it.
 

480sparky

Senior Member
Location
Iowegia
I know it's lame.... but... can you post those two sections for me.... :)


334.10 Uses Permitted.
Type NM, Type NMC, and Type NMS cables shall be permitted to be used in the following:
(1) One- and two-family dwellings.
(2) Multifamily dwellings permitted to be of Types III, IV, and V construction except as prohibited in 334.12.
(3) Other structures permitted to be of Types III, IV, and V construction except as prohibited in 334.12. Cables shall be concealed within walls, floors, or ceilings that provide a thermal barrier of material that has at least a 15-minute finish rating as identified in listings of fire-rated assemblies.
FPN No. 1: Types of building construction and occupancy classifications are defined in NFPA 220-2006, Standard on Types of Building Construction, or the applicable building code, or both.
FPN No. 2: See Annex E for determination of building types [NFPA 220, Table 3-1].
(4) Cable trays in structures permitted to be Types III, IV, or V where the cables are identified for the use.
FPN: See 310.10 for temperature limitation of conductors.
(A) Type NM. Type NM cable shall be permitted as follows:
(1) For both exposed and concealed work in normally dry locations except as prohibited in 334.10(3)
(2) To be installed or fished in air voids in masonry block or tile walls
(B) Type NMC. Type NMC cable shall be permitted as follows:
(1) For both exposed and concealed work in dry, moist, damp, or corrosive locations, except as prohibited by 334.10(3)
(2) In outside and inside walls of masonry block or tile
(3) In a shallow chase in masonry, concrete, or adobe protected against nails or screws by a steel plate at least 1.59 mm ( in.) thick and covered with plaster, adobe, or similar finish
(C) Type NMS. Type NMS cable shall be permitted as follows:
(1) For both exposed and concealed work in normally dry locations except as prohibited by 334.10(3)
(2) To be installed or fished in air voids in masonry block or tile walls
334.12 Uses Not Permitted.
(A) Types NM, NMC, and NMS. Types NM, NMC, and NMS cables shall not be permitted as follows:
(1) In any dwelling or structure not specifically permitted in 334.10(1), (2), and (3)
Exception: Type NM, NMC, and NMS cable shall be permitted in Type I and II construction when installed within raceways permitted to be installed in Type I and II construction.
(2) Exposed in dropped or suspended ceilings in other than one- and two-family and multifamily dwellings
(3) As service-entrance cable
(4) In commercial garages having hazardous (classified) locations as defined in 511.3
(5) In theaters and similar locations, except where permitted in 518.4(B)
(6) In motion picture studios
(7) In storage battery rooms
(8) In hoistways or on elevators or escalators
(9) Embedded in poured cement, concrete, or aggregate
(10) In hazardous (classified) locations, except where permitted by the following:
a. 501.10(B)(3)
b. 502.10(B)(3)
c. 504.20
(B) Types NM and NMS. Types NM and NMS cables shall not be used under the following conditions or in the following locations:
(1) Where exposed to corrosive fumes or vapors
(2) Where embedded in masonry, concrete, adobe, fill, or plaster
(3) In a shallow chase in masonry, concrete, or adobe and covered with plaster, adobe, or similar finish
(4) In wet or damp locations
 

480sparky

Senior Member
Location
Iowegia
agreed.. what are your thoughts?

Personally, I've never felt all warm and fuzzy about sticking NM to the bottom of the joists just because a drop ceiling is going up. I'd rather have it all up above the bottom of the joists (drilled through) so 4 months from now, when the owners get tired of the 60's look in their basement, it's ready for drywall.
 

SiddMartin

Senior Member
Location
PA
I wouldn't--yet that's just me looking out for the next person who decides to remove the drop ceiling :D

i've been in some old houses that don't even have a drop ceiling and the rx is crossin the joists

but i do understand your point, lookin for NEC requir. though
 

SiddMartin

Senior Member
Location
PA
Personally, I've never felt all warm and fuzzy about sticking NM to the bottom of the joists just because a drop ceiling is going up. I'd rather have it all up above the bottom of the joists (drilled through) so 4 months from now, when the owners get tired of the 60's look in their basement, it's ready for drywall.

i would never suggest drywallin the ceiling in a b-ment, IMO

edit to add: unless it was framed down to create a chase, but still....
 
Last edited:

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I approached it differently:
334.15 Exposed Work.
(C) In Unfinished Basements and Crawl Spaces. Where cable is run at angles with joists in unfinished basements and crawl spaces, it shall be permissible to secure cables not smaller than two 6 AWG or three 8 AWG conductors directly to the lower edges of the joists. Smaller cables shall be run either through bored holes in joists or on running boards. NM cable installed on the wall of an unfinished basement shall be permitted to be installed in a listed conduit or tubing or shall be protected in accordance with 300.4. Conduit or tubing shall be provided with a suitable insulating bushing or adapter at the point the cable enters the raceway. The NM cable sheath shall extend through the conduit or tubing and into the outlet or device box not less than 6 mm (? in.). The cable shall be secured within 300 mm (12 in.) of the point where the cable enters the conduit or tubing. Metal conduit, tubing, and metal outlet boxes shall be connected to an equipment grounding conductor.

In 99.9% of the situations I've seen if there is a suspended ceiling it's not an "undfinished basement"
 

SiddMartin

Senior Member
Location
PA
I approached it differently:
334.15 Exposed Work.
(C) In Unfinished Basements and Crawl Spaces. Where cable is run at angles with joists in unfinished basements and crawl spaces, it shall be permissible to secure cables not smaller than two 6 AWG or three 8 AWG conductors directly to the lower edges of the joists. Smaller cables shall be run either through bored holes in joists or on running boards. NM cable installed on the wall of an unfinished basement shall be permitted to be installed in a listed conduit or tubing or shall be protected in accordance with 300.4. Conduit or tubing shall be provided with a suitable insulating bushing or adapter at the point the cable enters the raceway. The NM cable sheath shall extend through the conduit or tubing and into the outlet or device box not less than 6 mm (? in.). The cable shall be secured within 300 mm (12 in.) of the point where the cable enters the conduit or tubing. Metal conduit, tubing, and metal outlet boxes shall be connected to an equipment grounding conductor.

In 99.9% of the situations I've seen if there is a suspended ceiling it's not an "undfinished basement"


agreed, that is what i was looking for. The basement is finished.
 

480sparky

Senior Member
Location
Iowegia
i would never suggest drywallin the ceiling in a b-ment, IMO

edit to add: unless it was framed down to create a chase, but still....

I could care less what the HO wants to do. Drop ceiling... drywall... cover it with dylithium crystals for all I care. I just drill the joists and 'git-er-done'.
 

SiddMartin

Senior Member
Location
PA
I could care less what the HO wants to do. Drop ceiling... drywall... cover it with dylithium crystals for all I care. I just drill the joists and 'git-er-done'.

I would cringe when the HO wants to add an outlet on the 1st floor, you walk into their b-ment, and wa-la, finished drywall. Now we cut access holes.. and everything else. but hey, they want it, they gotta pay for it.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Personally, I've never felt all warm and fuzzy about sticking NM to the bottom of the joists just because a drop ceiling is going up. I'd rather have it all up above the bottom of the joists (drilled through) so 4 months from now, when the owners get tired of the 60's look in their basement, it's ready for drywall.
All that requires is strapping, which is 1x's attached perpendicularly to the joists.
 
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