Making electrical cutouts
Commonly used methods
Method 1: Use a hot knife
Method 2: Use a router
How about using a circular saw with a large dado blade on it? the depth could be controlled precisely, without the inherent danger posed by a chainsaw--electric or otherwise.
Although it is not as quick or flexible as routing/cutting channels in the interior foam, running metal or plastic conduit inside the forms before the pour seems to offer better protection from a possible errant nail later. I think I�m like most folks: I normally don�t turn off the electrical power before hanging a picture.
Joe Wallace- Joe Wallace Construction
I use a chain saw to cut the chases for the wiring. I have the electrician go through and mark where they want the chases. I can cut all the chases in a 4000 sq.ft. house in less than 10 minutes. I have used a hot knife and while it is clean it is very slow. A router is a little faster but doesn't clean the channel as it is cut so another pass is required to clean the material out.A chainsaw cleans the channel as it cuts. Romex wire friction fits in the channel very well.
EDITOR�S NOTE: Other contractors have also mentioned that an electric chain saw is great for making electrical cutouts. Some say they use a c-clamp or some other device attached to the blade to act as a depth gauge so the cut is exactly the desired depth. Electric chain saws have become quite light, maneuverable, and inexpensive. But like all chain saws they can be dangerous, so be careful.
Thanks to Joe Wallace for giving us the details on this and the other methods.
Jim Perrow- Wolf Creek Enterprises
I prefer to run conduit inside the wall before the pour. Ask your electriction for several rolls of plastic flexible tubing used by electritions. I call it smurf tubing. Run the tubing inside of the foam form and poke a hole in the form where ever you want an outlet or switch. Continue to run tubing from outlet or switch to switch until you make a home run. You do not need to router or hot knife. The tubing is embedded in the concrete during the pour. No electrical inspector will ask you to install plates over the "studs" as they do in wood framing. It's easy to do and you can save money by doing part of the electrical work yourself, no license is needed.
Pieter VanderWerf- Building Works
The contractors I've talked to say the hot knife makes a very clean cut, and a router is faster but a lot messier.
Jean-Marc Bouvier- J-M Bouvier Carpentry
I also prefer the electric chainsaw. Its quick and you can reach heights without ladders. I had nylon wheels of different diameters made that I bolt through the end of the saw on either side of the blade. Using washers and double nuts to hold the assembly, this arrangement works great.