Romex between furring in finished garage.

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Nicksab

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Marin county california
Hey everyone

I need to run a couple of 14/2 and 12/2 in a garage. The ceiling of the garage will be finished with 2 layers of 1/2" type x on furring strip at 12" O.C.
I need an alternative to drilling 5 holes thru 20 2x8 floor joist.
can I staples the romex to the bottom of the floor joist between the 1x4 furring strip?

I know it can be done but I am completely sure if it will meet NEC 300.4 requirement such as having the nm clearance from framing members.

Any help would be appreciated

Thank you
 
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The OP is a contractor in Ca and is allowed to do the work as an inspection will be gotten for this job. Feel free to help with this
 
My feeling is if you keep the wires 1 1/4" off the furring then it is compliant. Personally, I would drill the joist
 
Nicksab said:
Thanks Dennis. I am just concerned about the structural integrity by drilling that many 3/4 holes. On the other hand, having the romex right on the back of the drywall does not feel right.
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If you space your holes right, there shouldn't be a problem. IBC has guidelines for where you can place holes in joists.

As for multiple holes, I don't think I've ever seen specific guidelines, but I was told by an inspector once - whatever size holes you're drilling, you must have that much lumber between holes.

I don't know where he got that, but you might inquire with your AHJ
 
I don't think you will have any issues drilling and weakening the structure. Even if they were structural 2x8s you can still drill through but ask the engineer as to where you can drill.

Happy Drilling!!!
 
Welcome to the forum!

Nicksab said:
Hey everyone

I need to run a couple of 14/2 and 12/2 in a garage. The ceiling of the garage will be finished with 2 layers of 1/2" type x on furring strip at 12" O.C.
I need an alternative to drilling 5 holes thru 20 2x8 floor joist.
can I staples the romex to the bottom of the floor joist between the 1x4 furring strip?

I know it can be done but I am completely sure if it will meet NEC 300.4 requirement such as having the nm clearance from framing members.

Any help would be appreciated

Thank you
Click to expand...

Thru solid dimensional lumber, your maximum hole size is H/3, or ~2 3/8" in a 2 x 8. The holes should not be any closer than 2x hole size from one another, nor within 2" of the top, bottom, or ends.

If you have just 5 12/2 and 14/2 cables, two holes that are 1" in diameter are plenty big enough to pull that thru. Personally, I'd snap a line or tie off a line to get perfectly straight holes, to make pulling as easy as possible, and go ahead and drill out a third 1" hole and string it for future use. Make sure all are level, and use a new paddle bit (1" paddle bit $3) to get clean holes with no splinters or wood fingers in the way.

A few Oatey access panels at the ends, about 10$ each, will give you access to that set of holes and string should you ever need it. It will take all of 5 minutes to drill another set of holes and string it vs having to blind drill later on and potentially hit plumbing, wiring, ductwork, insulation, etc. Setting the two access covers would take 30min-1hr.

There is no way I'd staple to the bottom of the joists in this case. Driving staples overhead, 3 every 3rd joist (for 5 cables and support every 4.5'), and the risk of hitting the wiring with a sheetrock screw or worse, cutting in a future can light and running a holesaw thru all 5 cables are all risks I'd just not take.
 
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Nicksab said:
Hey everyone

I need to run a couple of 14/2 and 12/2 in a garage. The ceiling of the garage will be finished with 2 layers of 1/2" type x on furring strip at 12" O.C.
I need an alternative to drilling 5 holes thru 20 2x8 floor joist.
can I staples the romex to the bottom of the floor joist between the 1x4 furring strip?

I know it can be done but I am completely sure if it will meet NEC 300.4 requirement such as having the nm clearance from framing members.

Any help would be appreciated

Thank you
Click to expand...

You said a couple of cables, how many are you actually running? You could put 4 cables in each hole before the derating will lower the ampacity below the normal 15 amps for #14 and 20 amps for #12 so you might not need many holes.

In your installation the furring strips are the framing members so you could attach to the underside of the joists if you maintain 1.25" from the edge of the strips.
 
Are you running and stapling the romex perpendicular to the joists and parallel with the strapping? If so it should not be and issue we do that all the time in New England. Just keep it an 1-1/4" from the strapping.

If you decide to drill holes I would keep the holes on the first third of the joist on either end and two inches or more from the bottom of the joist and no larger than 2-3/8".
 
JFletcher said:
....The holes should not be any closer than 2x hole size from one another......
Click to expand...
do you know if that is part of a particular building code?

I once had a project where I had to drill 18 holes through each joist, and there were 30 joists. AHJ told me 1x hole size between holes.
 
James L said:
He didn't cite anything, though. You've given me food for thought
Click to expand...

It's been a while... I may have been thinking 2x radius, or for engineered lumber (TJIs). or a case of CRS.

2x8s for a load bearing floor are already suspect to me. If the plumber or HVAC guy hacked the crap out of them (notches are a totally different deal than holes), I'd probably staple along the bottom too. I was assuming everything else was correct, which is often times a bad or felonious assumption.
 
JFletcher said:
Welcome to the forum!



Thru solid dimensional lumber, your maximum hole size is H/3, or ~2 3/8" in a 2 x 8. The holes should not be any closer than 2x hole size from one another, nor within 2" of the top, bottom, or ends.

If you have just 5 12/2 and 14/2 cables, two holes that are 1" in diameter are plenty big enough to pull that thru. Personally, I'd snap a line or tie off a line to get perfectly straight holes, to make pulling as easy as possible, and go ahead and drill out a third 1" hole and string it for future use. Make sure all are level, and use a new paddle bit (1" paddle bit $3) to get clean holes with no splinters or wood fingers in the way.

A few Oatey access panels at the ends, about 10$ each, will give you access to that set of holes and string should you ever need it. It will take all of 5 minutes to drill another set of holes and string it vs having to blind drill later on and potentially hit plumbing, wiring, ductwork, insulation, etc. Setting the two access covers would take 30min-1hr.

There is no way I'd staple to the bottom of the joists in this case. Driving staples overhead, 3 every 3rd joist (for 5 cables and support every 4.5'), and the risk of hitting the wiring with a sheetrock screw or worse, cutting in a future can light and running a holesaw thru all 5 cables are all risks I'd just not take.
Click to expand...

That makes sense. Looks like I am going to be drilling for awhile.

Any suggestion regarding a good auger bit for true 2x8 that are pretty well seasoned? ( about 50 years)
 
Knuckle Dragger said:
Are you running and stapling the romex perpendicular to the joists and parallel with the strapping? If so it should not be and issue we do that all the time in New England. Just keep it an 1-1/4" from the strapping.

If you decide to drill holes I would keep the holes on the first third of the joist on either end and two inches or more from the bottom of the joist and no larger than 2-3/8".
Click to expand...

Exactly. I am talking about running the romex perpendicular to the 2x8 and parallel to 1x4 furring. The SE is only allowing 1-1/8" holes in the middle span of the beam
 
JFletcher said:
It's been a while... I may have been thinking 2x radius, or for engineered lumber (TJIs). or a case of CRS.

2x8s for a load bearing floor are already suspect to me. If the plumber or HVAC guy hacked the crap out of them (notches are a totally different deal than holes), I'd probably staple along the bottom too. I was assuming everything else was correct, which is often times a bad or felonious assumption.
Click to expand...


It is a old building. The whole floor is true 2x8 joist. And yes the plumber already run the 3/4" copper in the middle .
 
infinity said:
You said a couple of cables, how many are you actually running? You could put 4 cables in each hole before the derating will lower the ampacity below the normal 15 amps for #14 and 20 amps for #12 so you might not need many holes.

In your installation the furring strips are the framing members so you could attach to the underside of the joists if you maintain 1.25" from the edge of the strips.
Click to expand...

I need to run 6 14/2 and 2 12/2. Maybe one or two 14/3 and a # 10 for the oven I believe.

The biggest issue is my panel is south of the building and to run the romex south/north for some switches and outlet. The joists are running west to east
 
JFletcher said:
It's been a while... I may have been thinking 2x radius, or for engineered lumber (TJIs). or a case of CRS.

2x8s for a load bearing floor are already suspect to me. If the plumber or HVAC guy hacked the crap out of them (notches are a totally different deal than holes), I'd probably staple along the bottom too. I was assuming everything else was correct, which is often times a bad or felonious assumption.
Click to expand...

The SE wants the width of the joist as spacing between holes so one hole every 8"
 
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