COMMUNITY FORUM

gtillotson

03:06AM | 04/14/03
Member Since: 11/26/02
33 lifetime posts
Bvelectrical
Due to budget constraints, I will be handling the electrical work on a bedroom addition and could use advice on running EMT. I am used to old work, so I have no problem with the fundamentals (circuit planning, bending conduit, panel work, etc.), but I've never had the pleasure of working in a completely open space before.

My biggest concern is avoiding code violations with the notching since those errors would be hard to fix. This will be all EMT with no armored cable.

I have the general guidelines for notching (not exceeding 1/4 the width on a load bearing stud, etc.) but could use tips and advice.


Lawrence

03:40PM | 04/14/03
Member Since: 11/14/00
333 lifetime posts
If you are working in an open wall space, I would use NM-B (sheathed electrical cable) instead of EMT (conduit) and drill circular holes through the heart of the studs instead of notching for EMT. 3/4 inch circular holes in the center do not weaken the stud nearly as much as notching. (Circles distribute force more evenly than squares or rectangles). Also, sheathed electrical cable is INCREDIBLY easier to use than threading THHN wire through conduit. You can just thread the sheathed electrical cable wire through the center holes in the studs instead of doing all the notching, threading, securing, etc. Ten minutes of work instead of hours.

If your local code requires EMT for all wiring (like in Chicago), then there are metal plates you should nail on tthe edge of the notch that not only protect the EMT from inadvertant nails/screws, but also reinforce the stud a bit. The ones that reinforce wrap around the sides of the stud, as opposed to just tacking onto the face of the stud.

You could also put some sort of insulation between the conduit and the protective plate so that a ground fault does not convey through the protective plate, thereby shocking anyone who inadvertantly nails through it.

Joe Tedesco

04:24PM | 04/14/03
Member Since: 07/27/02
141 lifetime posts
Code reference to answer your specific question.

300.4(A)(2) Notches in Wood.

Where there is no objection because of weakening the building structure, in both exposed and concealed locations, cables or raceways shall be permitted to be laid in notches in wood studs, joists, rafters, or other wood members where the cable or raceway at those points is protected against nails or screws by a steel plate at least 1.6 mm (1/16 in.) thick installed before the building finish is applied.

Exception: Steel plates shall not be required to protect rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, or electrical metallic tubing.

gtillotson

05:13PM | 04/14/03
Member Since: 11/26/02
33 lifetime posts
Great advice -- thanks. I am in Chicago, so it is all EMT here. I'll be sure to find the best plates and insulate the conduit.

Joe Tedesco

06:32PM | 04/14/03
Member Since: 07/27/02
141 lifetime posts
The rule above applies only if the NEC is adopted in your area.

Have you checked with your local electrical inspector for rules that can be found in the Chicago Electrical Code?

Is this job going to be inspected, and are homeowners permited to take out electrical permits to perform electrical work in Chicago?



gtillotson

06:45PM | 04/14/03
Member Since: 11/26/02
33 lifetime posts
I am in Oak Park, on the border of Chicago, and yes homeowners can get permits for their own electrical work. I will get local codes once we are closer to construction (still two months out).

iwire

10:26AM | 04/15/03
Member Since: 04/14/03
6 lifetime posts
If it was my house I would not notch the studs for EMT, Drill holes and use short sections of EMT with couplings.

You may find the building or framing inspector will not accept notchs

[This message has been edited by iwire (edited April 15, 2003).]

Lawrence

10:28AM | 04/15/03
Member Since: 11/14/00
333 lifetime posts
quote:
Where there is no objection because of weakening the building structure

That brings to mind another problem: you should make sure that the load-bearing wall does not need the support of a full 2x4 without notching. Sometimes notching is inconsequential because the load-bearing wall does not support that much weight. But I have a load-bearing collumn of 4 2x4s that hold up the entire ceiling of the first floor of a 3-story building. Notching that collumn could collapse the ceiling, which, in the worst-case scenario, could collapse the building. You might want to add a few belt-and-suspenders supporting studs just to make sure that the notching does not eliminate needed support. (I did so when adding some plumbing: not much work and it can't hurt). You can also turn the added studs sideways so as to avoid notching them.

....

[This message has been edited by Joe Tedesco (edited April 17, 2003).]

gtillotson

10:52AM | 04/15/03
Member Since: 11/26/02
33 lifetime posts
Thanks for all the help. If there are no real drawbacks to multiple couplings and short sections, I may try that option. There are only two load-bearing walls in this addition, so I'll be careful, and with the rest I'll check on notching options. I agree that the EMT rules are a headache, but there is a certain elegance and permanence to it all when you are done.
Click_to_reply_button Inspiration_banner

INSPIRATION GALLERY



Post a reply as Anonymous

Photo must be in JPG, GIF or PNG format and less than 5MB.

Reply_choose_button

captcha
type the code from the image

Anonymous

Post_new_button or Login_button
Register

Follow_banner_a
Newsletter_icon Google_plus Facebook Twitter Pinterest Youtube Rss_icon
 
webapp2