Hi Dan, You can buy plastic electrical conduit. It is a lot like the PEX used for water. I don't think it comes in 3 inch diameters but it can be had up to about inch and a half for sure.
pull half a dozen strings through it before you pull it up and you should have no trouble pulling future wires up the conduit. They make junctions and unions and all sorts of fittings for the various sizes. Code may vary a little but usually one bores holes through the ceiling joists to pull wire through or staple it along the sides. I see no reason why you wouldn't staple it over the top of the ceiling joists but usually you would not use the rafter part of the roof member. They then just bury the lot in the insulation. ----- Original Message ----- From: Dan Rossi To: blindhandyman@yahoogroups.com Sent: Monday, September 14, 2009 11:05 AM Subject: Re: [BlindHandyMan] spray insilation question. I am planning on having cellulose blown in sometime in the near future. They said they can use a 3/4 inch nozzle since they will have to drill through the mortar joints they want to use as small a nozzle as possible. Not only do they have to drill through the mortar joints, but then they have to drill through the wood cladding beyond the airgap behind the brick to get to the voids between the studs. I may hold off on having the attic done until I do some rewiring first. I'd rather not have to dig through 12 inches of cellulose to get to all the fixtures. Here is a vague plan, and a couple of questions. My house is balloon construction, so the joist bays run from the attic straight down to the basement. I've already pulled one set of wires from the second floor through to the basement. Anyway, I was thinking of trying to find some 3 inch flexible tubing, similar to the 4 inch flexible pipe I used for drainage around the basement door well. I would run this flexible tubing down from the attic to the basement in one or two places before having the insulation blown in, that way I would have a wire chase in place for future wiring projects. Does this kind of flexible tubing exist? Is there a reason why I wouldn't want to do this? Secondly, what is the code for running wiring through attics with blown in insulation? It seems like it would be a total pain in the ass to just bury the wiring under the insulation. Can you staple the wiring to the sloping rafters and then drop straight down from the rafter to the fixture in the ceiling below? It would make it quite obvious where the fixtures are, and you could easily see the wiring, but there would be these vertical wires scattered around your attic. Is that cosher? -- Blue skies. Dan Rossi Carnegie Mellon University. E-Mail: d...@andrew.cmu.edu Tel: (412) 268-9081 [Non-text portions of this message have been removed]