New Building

Status
Not open for further replies.
N

NEW-EE

Member
I have a new project that I needed to get some opinions on what is the best way to approach my issue. I'm working on the design for a new 2 story office building approximately 40,000 sq. ft. (20,000 each floor). As I have been told by the client, the building will hold only general offices, not doctors, dentists, etc. type offices. Right now I'm designing the shell work and trying to figure out how many general purpose circuits (receptacles, copy machines, fax machines, etc) to bring into each future tenant space. The structural columns are approx. 23' on center and I'm putting a junction box in between each structural column and home running back to the electrical room located on each floor. Any ideas on the best approach on how to figure out how many circuits I need to bring into each junction box that I have located between the structural columns? Thanks.
 
mdshunk. Yes I thought about doing it that way as well and suggested it but the client wants us to bring in circuits so we don't distrupt the other tenants as new tenants move in. I didn't agree that is the best approach...but what the clients want the clients get...
 
Is there going to be a central hallway on the 2 floors?
If so, why not design an electric room/closet on each floor, or at least on the second floor...trying to make them centrally located. I have not seen bus duct installed on a building of this size before, there is always a first time.
 
Pierre, Yes there is a cental hallway on both floors and yes there is an electrical room on each floor that is centrally located. I have a distribution board in the first floor electrical room feeding three 480/277V, 3ph, 4W panels. (1st & 2nd floor lighting & 1 for Mechanical equipment). I then was providing step down transformers and a two section 208/120V, 3ph, 4W in the 1st & 2nd floor electrical rooms for plugs, etc...
Originally that is all I was going to provide and then as the tenants move in they can come off those panels for what they need. I'm trying to convince the client not for us to pipe into the shell space yet because nobody knows what type of offices are going in yet and how many circuits they may need. So far I haven't been successful on convincing them. They still want us to provide circuits into the shell spaces for the reason that as new tenants move in they don't want to disturb the other tenants. So this brings me back to my original question on any suggestions on the best way to determine on how many circuits I should bring in each junction box. Thanks for your opinions....
 
Why bring individual circuits at all? Why not distribute a few empty 1 1/2" and 2" conduits for subpanels from the hallway EC past the core into the tenant space and leave it at that. Individual tenants will decide how to layout their interior space and how many branch circuits they'll need. This way tenants won't have or need access to the common electrical closets, and the possibility for future sub-metering is simplified.
 
That was my original point with the client Lawnguyandsparky. To me it didn't make sense to bring in circuits yet BUT the client said they wanted too. I'll try to convince them of your suggestion. Thanks everyone....
 
Should I do it or not ?. ?

Should I do it or not ?. ?

I have a customer wants to add some light fixture in hall way. Where there is existing can lights close by . Customer does not want sheet rock cut. At the same time wants to be able to switch both of them separately. My question is? Can I used the grounding conductor as common neutral after I wrap the exposed wire with tape for both and then the old grounded conductor (white ) as switch leg for my new fixture . The switches box in very critical position. Any suggestion to accomplish my customer desire will be greatly appreciated. Thanks folks
 
nafis said:
I have a customer wants to add some light fixture in hall way. Where there is existing can lights close by . Customer does not want sheet rock cut. At the same time wants to be able to switch both of them separately. My question is? Can I used the grounding conductor as common neutral after I wrap the exposed wire with tape for both and then the old grounded conductor (white ) as switch leg for my new fixture . The switches box in very critical position. Any suggestion to accomplish my customer desire will be greatly appreciated. Thanks folks
Click to expand...


I hope you are joking. This violates too many sections of the NEC to even elaborate. The GROUNDING CONDUCTOR may NEVER be used as anything else. These circuits must be re-wired to allow seperate switching. Would you use the conduit as a neutral conductor? That would be the same thing as using the grounding conductor as a current carrying conductor.
 
When no specific equipment list is provided and you are given the task to provide 'rough-in' service, here are a few things that I learned from the "old pro's".

Calculate the ampacity as per Tables 220.12 & 220.14 & 220.42.

A typical business office is allowed 3.5va/sq. ft. & 1va/sq. ft. for general receptacles will work out so that 1 to 2 circuits be allocated for an office or exam room. We typically have provided empty raceways to a group of like rooms (dental, optometry, patient care, etc) that can be finished at a latter time. This method usually consumes more circuits with lower ampacity requirements, but eliminates the installation of new home runs back to the panelboards.


For a typical 'business office' that is used for medical purposes, this seems to work fairly well. Rough square footage for a 120 vac / 20 amp circuit can range from 85 - 150 sq. ft. depending on the type of occupant. Lighting seems to average 750 - 850 sq. ft. per circuit depending on the type of architectural design / occupant.

Hope that this is of some help. Please refer to a A.I.A. guide for more specific applications in the healthcare industry.
 
Status
Not open for further replies.
Top