I just puchased a brownstone in Chicago built in 1900. I need to update the electrical in the building. The walls are all plaster and in good shape. The Chicago electrical code requires conduit to be used for any electrical upgrades. There are two units in the building, and I was going to do one at a time. I was wondering if anyone has any ideas about how to do this without gutting the entire place?
Thanks,
dk
Replies
Do you have an attic? A basement or crawl space? More than two floors? If you're doing this yourself, as I'm doing, it's a different tradeoff of time spent working out clever ways to do things to avoid making big holes. For instance, if you have plenty of attic space, you may be able to put in a new plug by making the hole for it next to a stud, and another above it, just above the fireblock. Use this hole to drill thru the fireblock for a piece of EMT that reaches from the box to just above the block. But first drill thru the top plate from the attic, and feed a piece of wire or strong string down to where you can grab it thru the hole in the wall. Use this to pull a guide rod up. Push the top piece of EMT in thru the hole in the wall, onto the guide rod, and up thru the top plate. Then feed the bottom piece up into the wall cavity and down to the box. Connect the EMT to the box, then nail the box in place. Next, connect the two pieces of EMT just above the fireblock. Finally, finish out the run in the attic. Check out a tool called the D'Versibit for making holes in hard to reach places, it's basically a drill bit on the end of a very long and slightly flexible rod. It also doubles as a guide rod for EMT. You'll also want an angle drill and some short bits for it. Spring clamps are also handy to keep the EMT out of the way, and from falling out of its holes.
What is most important, though, is the ability to look at this as a bunch of interesting puzzles rather than as work that's worth some reasonable number of dollars per hour.
-- J.S.
there are various types of flexible conduit available today and something must be allowed in Chicago (check with your inspector for guidance) so that you can do what is described above without having to fish straight pieces of rigid conduit everywhere.
Can't blame the Chicagoans for having such strict electrical codes though (what with that big fire and all, 'cept wasn't that before electricity?).
:o)
If they'll let you use flex, the puzzles get a whole bunch easier, and the extra holes you might need to make get a whole bunch smaller. If you have a really big attic, big enough to run the D'Versibit down into the wall, with flex you might be able to do the job without the extra hole in the plaster. But that can be some real fancy fishing.
-- J.S.
It's my understanding that in Chicago you can use bx(I think it is now called nm) and flex for renovation in existing walls. It cannot be exposed. If you are not removing the plaster you can fish bx or flex inside of the walls to a box located in the attic or basement. From there you have to use EMT. One problem I had is when I later rerenovated an area and exposed the bx I had to remove it and install emt.
NM stands for Non-Metallic, it's the code word for Romex. BX, IIRC, is like flex, but with the wires and some extra stuffings in it so you can't pull more wires thru it. But that's a memory from over 40 years ago. It could be wrong.
-- J.S.
John, prewired BX cable is now commonly called type MC (metalic cable). We use it a lot in commercial work. There are also some special fittings and a cutting tool available. The fittings snap on both the cable and into a box knockout. The cutting tool will cut two turns of the flexible metal without touching the insulating plastic just inside the cable or the insulation around the wires. If it is allowed by local code, it would be just the ticket for this type of job.
Dave