Originally Posted by Sammy2
Everyone keeps calling it a pipe. It is a raceway or conduit.
Per the national electrical code unless adopted by local jurisdiction, a permit is not required when installing low voltage (under 50 volts to ground) but if you run cabling through a mechanical chase, duct or plenum it must be plenum rated which is typically indicated by the CL designation which means "ceiling". Ceiling space above T-bar ceilings are very commonly used as return air plenums in commercial construction but not so much in residential construction. The CL designation means that the outer sheath of the cabling produces limited smoke and will not easily catch fire itself.
If you add in 120 volts not shown on the plans some jurisdictions get persnickety about it not being on the plans. Others could care less in residential construction.
You're really splitting hairs on this one. If you get the PVC pipe from the plumbing section and use it as a conduit, it's still pipe that's just been repurposed. Technically, it is now conduit, but that's just semantics at this point. You can use PVC pipe as a conduit or raceway for low voltage wiring (I did refer to the pipe as a raceway in my post, BTW). In my house I was just lucky enough to find a natural space that I could use as a raceway between floors. I was able to locate the spot where I needed to drill a hole in the basement ceiling to complete the raceway to the 2nd floor. A conduit or raceway is just a pipeline or tunnel, if you like, used exclusively for running wires from one location to another in a building structure. You need to check local building codes regarding low voltage wiring as it is different from state to state or possibly even by county. The comment about 120-volt wiring is why I indicated that you should have your electrician perform the task. They should be able to modify the building plans to add any new wiring under the current permit and get it inspected all at once.
FWIW, if you look in the electrical section at your local home supply store for conduit you're going to find material that looks almost exactly like pipe used for plumbing. The only difference is the variety of materials used for the different applications. PVC is used for both so 2" PVC pipe should easily double as conduit under your local building codes.
If the whole issue of whether a permit is required or not, just install the conduit or raceway between floors and then install the internal wiring after the house passes inspection. Since the conduit contains no wiring it won't violate any building codes and cause the inspection to fail. The inspector will just check for installed wiring against the house plans and make sure everything's up to code. However, as I stated previously, you really should take care of any perimeter wiring prior to the drywall and insulation being installed. This includes any alarm wiring or outside lights or cameras and you may need a permit to get it to pass inspection. Wiring that runs through internal walls can be installed at any time with virtually no problems.Edited by captain_video - 2/27/13 at 10:40am