Doing a job right now, a "tenant improvement" where a fairly large commercial space (5000 sq. ft.) is being divided up into a number of small rooms, each with multiple circuits. The basic construction is light steel framing, covered with drywall and capped with a suspended ceiling.
Wiring method is EMT. As modest as the area is, there are over two panels worth of circuits to be used- most of the ordinary 20-amp, 120-volt variety.
The EC has been using this job as a place to 'store' electricians as other jobs encounter delays. As a result, there have probably been a dozen individuals at work, running EMT as they see fit, with perhaps imperfect attention to the prints. No two men have thought even slightly alike in the ways they ran their work.
Given such a job, how are you likely to organize your conduit runs / wire pulls? Any tips or tools particularly helpful for working with light steel framing?
Since the prints are going to be useless and as builts will be hard to accurately create, I would give them all sharpies and have them identify each EMT run as they do it. There should be someone actually coordinating this job and making sure they get a decent set of as builts, spot checking it before they close up the walls but I bet that is rare.
The guys who are doing the addition at my wife's place are getting a lesson on this. She made sure a set of accurate as builts were in the contract and now the 3d EC on the job is trying to figure out what the first 2 did. She has her guys spot checking the panel directories and circuits. They tried to turn over the job with directories saying stuff like "lights" and "receptacles" with no other indications and some of those were wrong.
The guy who was supposed to be the job super was fired and his boss is offering her a job
OK ... here are some of the things that seem to work best for me:
Your 'best' pipe runs are straight up to / through the top plate. These, while quick, will have you consume an amazing amount of pipe. Forget box offsets, etc ... support the pipe using the Caddy CS812 (for regular depth boxes). The clip will let you use the 'inboard' and center KO's of the box.
Place your data pipes first. As these are 3/4" pipes, you'll want to bend the small pipe to go around the larger data pipe, rather than to opposite.
Punch through the top plate using either a stud punch, or a carbide hole saw; the Ideal 36-301, though sold for 3/4 pipe, works quite well for 1/2 fittings. You don't want a big hole, as you will also need to mount a box right there. Face the boxes INTO the rooms, and run your home runs down the hallway. This will let you land your 'feeder' pipes into the backs of the boxes. Set the boxes for receptacles on the 'room' edge of the top plate, and the lighting boxes on the 'hall' side. There's room on the top plate for two runs of pipe.
Plan each pipe run in the wall to have only ONE circuit on it. If there are several circuits in the room, plan on having several separate pipes in the wall. Trust me, it's pure insanity to try to separate circuits in every box! 1 pipe = 1 circuit. This makes the wire pulls easy, and you might even wind up following the print!
Use the boxes on the top plate to combine circuits into 3/4" "feeder" pipes for the home run. Consider using 4-11's on the top plates, for more splicing room.
Where wood blocking is placed in the walls, use DEEP boxes. This will place the KO's beyond the wood - and you probably won't have a lot of room for offsets.
When running between boxes, "cross" your pipes. For an example, imagine that your studs are on the LEFT side of the box. Use the left KO of the box on the left to feed a pipe that runs right to the second box at some distance to the right. After the pipe passes through the last stud, it has room to bend down and hit the center KO of the box to the right, using the pre-punched holes in the studs for passage.
This gives you two problems above each box. Problem #1 is that the holes in the studs are not above the boxes. Using the example from above, here's how you address it: pipes that curve to the left have a slight 'kick' to line up with the holes; pipes that turn to the right go straight up, turn, then have a slight offset to line up with the holes.
Still, you might want to enlarge the existing stud holes. The best tool for doing this is a RIGHT-angle aviation snip- see Malco AV-9. I think Harbor Freight also has a version out. The offset angle of the blades makes reaching into the hole and cutting a pleasure.
In the last post, I discussed how to pipe light steel framing. Now, for the wires ....
Jobs seem to be specifying separate neutrals these days. My latest panels even had neutral bars running in line with the breaker spaces. Customers also seem to like to see a ground wire in the pipe - beats me where this silliness got started!
Anyway, it's a real help to have a matching colored strip on the neutral wires. Likewise, if you have an 'isolated ground' wire as well, get the green wire that has the yellow stripe on it. OK, so you have to plan ahead, and push the supply house a bit - it's worth it!
Likewise, it's worth it to reserve some other color - violet / purple seems popular - for your travelers.
Rule of thumb (forget the book here!): 4 circuits in a 3/4 pipe, ONE in a 1/2" pipe. Best fish tape for use on these jobs is the Ideal "Zoom" fish tape. This tape is far more flexible than the usual steel one, and the rounded tip means you can push it in a pipe full of wires without fear of damaging anything.
Since panels seem to always have the wrong KO's on them ... save yourself some grief at the start by staging everything through a gutter; punch the gutter as needed. The "Marksman" tool is great for placing your holes. The Ideal carbide cutters outperform KO punches for 3/4 pipe; just remember: slow RPM, maybe a touch of oil, and lots of pressure.
There is no substitute for planning! DON'T place one pipe, let alone pull even one wire, without having a panel schedule completed.
Inspect the dickens out of the work before the walls are closed in. Photograph everything. "Index" the prints by painting a room ID on the floor, matching the marks on the print.
It's a real help to paint / color code your boxes. It's pretty embarrassing to find a receptacle installed in what was supposed to be a data box - or (more common) the 2-gang mud rings put on the wrong boxes. "Dykem," though pricey, dries almost instantly, and is available in blue or red.
Go around with an impact driver and inspect EVERY set screw. Having a pipe come apart in the wall is no fun.
Speaking of prints: Have / make up / photo & print several 'sets' of each drawing. Here's what you do with them: - The first one you highlight to make clear exactly where each circuit goes. - The second one you highlight to show your top plate boxes, and the home runs that tie into them. - The third one you highlight as each stage is completed. For example, I'll highlight a box when I hang it, then use the highlighter to connect boxes when the pipe is completed. - Other copies can be handed to the crew, placed in each room etc. Get some special tape from Office Depot that won't hurt the drywall when you remove it!
"Prints" need not be official, professionally printed copies of the 'real' prints. Instead, I find it helpful to take a picture of each room (or area), then use my computer to enlarge and print out just that area.
Highlighting: Highlight first in yellow. This will let you draw over it in blue for the next step.... for example, yellow when you put in the pipe, blue when the wires are pulled through it, a final green when devices are placed.