Wiring code -- across attic floor joists

I need to add a couple of electrical circuits that will run across the floor joists of an attic. The attic is accessible, but it has a low ceiling height, so the attic is not (and never will be) a usable living space. There is no floor in the attic space -- just the open joists which are the ceiling joists for the rooms below.

Since the new circuits will be running across (perpendicular to) the open joists, is it okay to just run a nailing board across the top of the joists and staple the new wiring on top of the nailing board? That would be a lot easier to do than drilling through the joists and running the wires through the drilled holes.

Is the nailing board approach okay according to the NEC requirements?

Reply to
TomR
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Usually you will already have a 2x4 running perpendicular to stiffen the joists, which you can use as a running board, or if you need to, install your own.

Reply to
RBM

Also, the Nec defines an attic as being "accessible", if it has permanent stairs or ladders to access it. If you just have a scuttle hole, it's not considered accessible, and you can staple the cables perpendicular on top of the joists except for within six feet of the scuttle hole

Reply to
RBM

Right idea but you staple the wire to the side of the running board. Then you are not walking/crawling on it and if you do put some decking up there, it is not sitting on the wire.

Reply to
gfretwell

OR if the destination of the wire allows it, run them on the underside of the rafters so you won't tread on the cables if and when you have work to do up there.

Reply to
EXT

I've seen lots of houses here in AZ where they just lay the wire on top of the joists, no nailing board. Just a few staples here and there to hold the wire down.

Reply to
Ashton Crusher

well if you EVER want to store stuff up there, your far better off to run the wires thru the joists...

when this home was built in 1950 they ran the wires on top of the joists and when 3 years ater i decided to add a floor it was a big hassle

Reply to
bob haller

The Nec still requires running boards if you are within 7 feet of the floor joists

Reply to
RBM

I'm sure they did it to piss you off

Reply to
RBM

If these are actually the bottom chord of a truss (2x4) DO NOT DRILL THEM.

Reply to
gfretwell

The trick for decking an attic with wires on top of the framing is to add 1x2s purlins to space the deck up 3/4" and clear all of the wires.

I had to do this in my attic. It also gets you by that "6' from the hole" problem.

If you have decent insulation up there you may even want to use thicker stock so you are not crushing your insulation.

Reply to
gfretwell

Okay, thanks. That's good to know.

The access to this attic space has a strange type of access. There's a small door in the back of a closet on the second floor, and behind that door is the top of a stairway that runs up from the first floor to the second floor. The were a couple of boards nailed across the sloped stairway "ceiling"(?) joists to form a makeshift ladder effect, and I can climb up those makeshift crossboards into the attic. I nailed better boards across the stairway ceiling joists to make it easier to climb up and into the attic. I guess that means it does have an existing makeshift ladder up into the attic, and I guess that may make it "accessible" for NEC purposes.

I think I'll just use running boards anyway, and I'll also stay away from the area within 6 feet of the access hole. That should cover me -- meaning whether the attic is "accessible" or not.

Reply to
TomR

That's a possible option, and I'll keep that in mind depending on where the circuits are running.

Reply to
TomR

That's good to know too. No part of the attic space is more than 7 feet high, so I'll use running boards even if I run the wires across the rafters above.

Reply to
TomR

I'm sure that I will never want to make this into a storage area of any kind. And, given the other options that are available (such as using running boards), I am not going to do any drilling or running of wires through the joists.

Reply to
TomR

Agreed but if it's a truss, can't you run the wires thru the truss (or should I say chords) with no drilling involved? That said, I doubt they used trusses in 1950 home construction but I'll let the OP tell us.

Reply to
Doug

Thanks everyone for all of the replies and suggestions. I just decided last night that I am going to be doing this, and I am going to be starting the work this morning. It was great to be able to post the question last night and then wake up this morning and all of the answers that I needed are right there waiting for me to read. This is an excellent Usenet group!

Reply to
TomR

It would take 2X8s in my "attic".

Reply to
clare

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