Supporting wire in the attic over joists

[Highbeam]

My panel is at one end of the shop and I need to run circuits up into the attic, down the attic and then turn 90 degrees run across the attic and drop down the walls to the outlets, disconnects, or whatever. I will have 12 gauge, 10 gauge, and maybe some 8 gauge romex cables to run in the attic for these ciruits. There will be long runs that are parallel to the ceiling joists which are 2 feet apart. Every four feet I have a flat 2x4 that runs perpendicular to the long wire runs.

My question, since I can't nail all the circuits to one joist, how often must a cable be supported when running in free air parallel to the joists. I know I can go two feet but how about 4? There will be a ceiling at some point and this will be inspected.

 

[pattenp]

Support/staple needs to be within every 4 1/2 feet and within 12" of every outlet or Jbox. Also any cable run across joist within 6' of an attic access hole must be run along a running board.

 

[Highbeam]

Awesome. I knew I would get some use out of those rat runs.

 

[LX-Markham]

LOL that's only the second time I've heard that term ^^^.
Two weeks ago my contractor called them rat runs.

I guess only engineers call them "joist bridging"

 

[tylernt]

Support/staple needs to be within every 4 1/2 feet

Do they still need staples even beyond 6' from an attic scuttle hole? Because every attic I've ever seen, has Romex everywhere with no staples whatsoever... including one that I know was re-wired by a licensed sparky and inspected by the AHJ.

 

[pattenp]

All I can say is the NEC says the cable is to be supported/secured at intervals not to exceed 4 1/2'. The only exception is cable that is protected within a raceway is not required to be secured within the raceway.

 

[tylernt]

All I can say is the NEC says the cable is to be supported/secured at intervals not to exceed 4 1/2'. The only exception is cable that is protected within a raceway is not required to be secured within the raceway.

I guess running perpendicular to ceiling joists, the cable is "supported" every 16" or 24" O.C. Running parallel with the joists, I suppose the insulation or ceiling drywall underneath might count as support.

 

[pattenp]

Nope. The support has to be done with staples, cable ties, straps, hangers, etc.

I guess running perpendicular to ceiling joists, the cable is "supported" every 16" or 24" O.C. Running parallel with the joists, I suppose the insulation or ceiling drywall underneath might count as support.

 

[tylernt]

Nope. The support has to be done with staples, cable ties, straps, hangers, etc.

Guess the inspectors in my area just have a really relaxed attitude towards life.

(Don't worry, when I added a circuit, I stapled... it's the only cable up there that's stapled, but I still did it.)

 

[Highbeam]

LOL that's only the second time I've heard that term ^^^.
Two weeks ago my contractor called them rat runs.

I guess only engineers call them "joist bridging"

As an engineer myself, I learned early on to use the common lingo for such things. It's the only way you can expect to get knowledgable responses from people that actually do this stuff.

 

[2Big2Ride]

All I can say is the NEC says the cable is to be supported/secured at intervals not to exceed 4 1/2'. The only exception is cable that is protected within a raceway is not required to be secured within the raceway.

Our old house in Vancouver, Washington that was built in 1992 was done as discribed, our current house in Texas that was built 1999 isn't even close. I think they used at most two staples per run and the attic looks a bowl of spaghetti.

 

[Falcon67]

Our old house in Vancouver, Washington that was built in 1992 was done as discribed, our current house in Texas that was built 1999 isn't even close. I think they used at most two staples per run and the attic looks a bowl of spaghetti.

SOP for years in houses. I've never seen a staple in a attic. None in ours that's for sure. In the shop, I used the bottom of the rafter bracing and some 1x to make cable trays.