I notice that Chicago-area members mention a metal-raceway requirement for residential [maybe ALL?] structures in the region. Is it possible this evolved from 1871?
An online article made me wonder of the requirement’s evolution. Sorry for the long URL, but it is an interesting account from the perspective of a Chicago telegrapher [the original digital communications/”chat room”] during the great 1871 fire. http://groups.google.com/groups?q=1871+group:comp.dcom.telecom.*&hl=en&lr=&ie=UTF-8&group=comp.dcom.telecom.*&selm=telecom23.242.1%40telecom-digest.org&rnum=1
Chicago's bad luck has probably saved thousands of lives, as it seems to be the basis of many, many code requirements. Remember that each time a body hits the floor in a disaster, we as code officials study it, learn from it, and determine if it could have been prevented.
The Chicago fire is credited as being the main reason for fire resistance rated construction requirements for exterior walls as they relate to proximity to property line. We don't want any buildings to burn down, but if they do we can live with it. What can not happen is a domino effect of buildings catching one another on fire.
Another contribution from Chicago is many of the cross-contamination provisions in the various plumbing codes. I have read that when Chicago was in its infant stage of being a MAJOR city, nearly 1/3 of the population was ill or dead from cross contamination from the potable water supply. They were getting drinking water from lake (Michigan? Superior?), and also directing their waste water into it. As a result, there was a huge outbreak of dysentary, killing several thousand people.
Ryan Jackson, Salt Lake City
Re: Metal-raceway requirement #154132 05/18/0406:28 AM05/18/0406:28 AM
Yes, Ryan and Bjarney, we have the metal raceway in all applications in Chicago. I've started seeing romex in the outer suburbs for new construction and we can use uf/direct burial cable for some apps like garages. And we still have our share of K&T. This doesn't guarantee quality or safety though-you should see what people try with metallic (" well the neutral is grounded, and the raceway is too, so the ground must be neutral...") I think it will be a while for romex.
I believe that the fire of 1871 did provide the current code philosophies, but you can still see frame buildings that are really 3"-4" apart, and these are 2 and 3 storey units. As far as the plumbing- yes, there were major outbreaks of contamination, so much so that in 1900 we did this: http://www.chipublib.org/004chicago/timeline/riverflow.html
Re: Metal-raceway requirement #154133 05/18/0408:25 AM05/18/0408:25 AM
Actually Ryan, the Chicago river used to flow into Lake Michigan - the river, of course, being the great waste repository, and the lake being the source of drinking water... well, maybe we've made great evolutions in logic through the years, hmmm?
The Army Corps of Engineers, at the request of the City, using dredges and such, actually reversed the flow of the river, via new causeways. IIRC, it was about the time of the Erie & Michigan (Illinois & Michigan?) canal project.
So I assume you guys in Chicago end up piping in wood framed builtings alot?
Something I have very few uses for most times, but have done. Might I say, it was a real pain. And, at one time conduit was the law of the land here as well. (black rigid in the '30s, in buildings over 3 stories)
I get to do alot of remodels of these buildings, and, I'm amazed that alot of it was done without notches, or threadless connectors. Sometimes I've come across things that were either bent while in the wall, or the studs were slid on the pipe, then nailed in place! How does one get a 10' stick into, and across a 16" stud wall?
You must fill us in. Do they frame differently to accomadate this?
Mark Heller "Well - I oughta....." -Jackie Gleason
Re: Metal-raceway requirement #154136 06/30/0402:25 AM06/30/0402:25 AM
Yeah, it's pretty much the standard here. That or Greenfield, which most places only allow for fished work or flexibility purposes. And the construction is pretty standard - regular 16" o.c. wood 2x4's on platform type construction...
My house (built in 1934) was black (lacquer?) RMC... the accepted use of EMT has made pipework much easier. Remember too, that back in "the day", most holes were made with bit & brace - a lot harder to "chew" a bigger hole that way. Also, IMHO, workmanship took a higher position than speed, even though the work would remain hidden lo these many years!
As far as running it (EMT) - usually just pop a 1" hole in the cap plate above your receptacle/switch location and insert a length of stick into it - length from end of pipe to back of bend is the top of your J box to above the floor joists above (2nd floor). As long as your tail (short leg of "L") will clear the rafters, you just jockey it into position, and turn it towards where your run goes once it pops into place.
You either come up, over, and down to the next box, or you drill sideways and go from box to box that way. The biggest problem with that method is it's more time-consuming than going up - you're only using 30" pieces to make the whole run (unless you notch).
Notching depends on the AHJ (or your boss) - we got real good on one job at notching the backside of the studs, and flipping the pipe into the space behind the basement wall and the studs, and rolling it down into the notch. Since it wasn't a load bearing wall, the AHJ didn't have a problem with it.
For 1st floor runs, we usually stub down (Height from bottom of box to FF +4") and run the pipe underneath in the basement, or drill sideways as described above.
It's a bear to learn, it takes more time, and a real pain sometimes. No offense to my cable-slinging brothers, but if I was designing my custom house, I'd never spec NM... nothing's easier than pulling additional wires into a pipe, as opposed to having to chunk out a wall for a simple "add-on".
It wasn't just the Great Chicago Fire.... When the "Columbian Exposition" (world's fair) was held (1895?), the world was treated to the first showcase of the uses of electricity. As you might guess, there were many, many fires caused by this new technology. This led directly to Chicago developing one of the first building codes, as well as the creation of UL. Since then, the Chicago authorities have resisted many newer construction methods; entire building types have come about due to peculiarities of the Chicago code. While today most of the resistance seems to come from unions fearing the loss of jobs, or the fear of the authorities of unregulated DIY work, the "new ways" aren't always the cats' meow, either.
Doug does a fine job of explaining the use of EMT in wood framed homes in this area. I just wanted to add that sometimes if the horizontal line for the conduit runs to an outside corner (inside the house), you can drill an extra hole or two and use lengths longer than 30". I usually think of these after I install the 30" pieces. It takes a lot of imagination and I have a lot of respect for the guys that do it. As in most work, after you've done it for several weeks, it's easy.