ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
VDE 0100 to introduce AFCIs
by sparky. 01/20/18 05:09 PM
MRI LED lights dimmer control replacement - wow!
by Potseal. 01/19/18 08:52 PM
Video: Inventor of the GFCI self-testing shocks
by Bill Addiss. 01/17/18 11:11 PM
FPE in Germany
by HotLine1. 01/17/18 07:07 PM
Fujifilm Recalls Power Adapter Wall Plugs
by Admin. 01/16/18 07:04 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 16 guests, and 14 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Trenching Concrete Floors #154059
02/20/04 11:02 PM
02/20/04 11:02 PM
J
Joey D  Offline OP
Member
Joined: Oct 2003
Posts: 259
Arlington MA U.S.
I am on a job in a apartment building where the floors are all concrete. The contractor is framming a few areas in he middle of the ceiling to install recesed lights in. He has cut a 2inch deep trench in the ceiling from one lowered ceiling to the new one. The floors are only 8" deep. Would this be a smart thing to do?

Building Codes & Related References
Re: Trenching Concrete Floors #154060
02/21/04 12:09 AM
02/21/04 12:09 AM
C
crash  Offline
Member
Joined: Oct 2003
Posts: 147
Calgary Canada
The only person who could answer that question is the Engineer who designed the building. If the engineer gave the contractor the go-ahead for this trench and the corresponding repair, then it should be okay.

Re: Trenching Concrete Floors #154061
02/21/04 05:36 AM
02/21/04 05:36 AM
I
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
I agree with Crash.

Any chance these are precast cement decks?

If yes as long as the pre-stressed cables inside are not cut it seems you can do a lot to them, with an engineers OK.

Without an engineers OK this sounds dangerous.


Bob Badger
Construction & Maintenance Electrician
Massachusetts
Re: Trenching Concrete Floors #154062
02/21/04 10:05 AM
02/21/04 10:05 AM
R
Roger  Offline
Member
Joined: May 2002
Posts: 1,716
N.C.
I agree with Crash and Iwire. A structural engineer would need to be involved, and it would seem to me that there would be some specific instructions to the cutting.

Roger

Re: Trenching Concrete Floors #154063
02/21/04 10:54 AM
02/21/04 10:54 AM
D
DougW  Offline
Member
Joined: Jun 2003
Posts: 1,143
North Chicago, IL
I was going to ask if they were Spancrete, or another type of cellular concrete. Taking 2" out of that could be, uh, problematic.

Get a Structural Engineer's opinion.

Re: Trenching Concrete Floors #154064
02/21/04 12:20 PM
02/21/04 12:20 PM
U
u2slow  Offline
Member
Joined: Sep 2003
Posts: 200
Salt Spring, BC, Canada
I work in mainly new highrise construction. Typical floors are 190mm (approx 7-1/2") and having to chip a shallow trench in the ceiling or floor (to bury BX cable or 1/2" ENT) has not been an issue with the engineers or inspectors so long as the steel isn't cut. Usually we don't have to go deeper than 1" or so, unless there's a spot where the rebar is too shallow and we have to go behind it.

Check with YOUR engineer first though [Linked Image]

[This message has been edited by u2slow (edited 02-21-2004).]

Re: Trenching Concrete Floors #154065
02/21/04 07:31 PM
02/21/04 07:31 PM
J
Joey D  Offline OP
Member
Joined: Oct 2003
Posts: 259
Arlington MA U.S.
Thanks. I was thinking the same.


Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Scott35
Scott35
Anaheim, CA. USA
Posts: 2,708
Joined: October 2000
Show All Member Profiles 
Top Posters(30 Days)
Admin 20
sparky 16
Potseal 15
Popular Topics(Views)
243,583 Are you busy
180,379 Re: Forum
170,856 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.019s Queries: 14 (0.003s) Memory: 0.9837 MB (Peak: 1.1360 MB) Zlib enabled. Server Time: 2018-01-21 20:04:57 UTC