This has to do with a recent post for residential service size

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jbelectric777

Senior Member
Location
NJ/PA
A contractor friend called for some advice on some multi family apts and sizing the service, He was confused because the architect drew 200 amp single panels in these very small apts, gas fired heat, hot water and drying/cooking. So we did the NEC calculation, turned out the building calculated just under 80KVA. The inspector off the record told him he would put an 800 amp service in, the service supply is 120/240 we concluded a 400 is of more than enough. This is a question to the moderators and skilled vets of the business, Why do these architects size these panels so high, its a complete waste of money when they only need 100's. My son is an architect and said "Dad, to be honest I'd call you on something like that because they dont teach us much mechanical stuff" he also said these days architects cant "sub out" services to an electrical engineer because everyones working cheaper due to the economy. My answer is to have the licensed electrician or an inspector be allowed to draw the electrical in, in NJ they let the electrician do it for one and two family dwellings only and after that it has to be a licensed design professional, as an inspector do you know how many times I reveiwed a plan and had to call and correct an engineer or architect? I cant even count it happened so much. Jim:mad:
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
The only reason to size larger than needed is if there is a possibility for larger loads later on. For apts this may be unlikely and does seem like a waste of money.
 

RICK NAPIER

Senior Member
Location
New Jersey
In NJ licensed electrical contractors can provide drawings for the following use groups. Personally as an inspector I am not willing to take on the added responsibility of designing a project on top of my current role.

Group B less than 7,200 square feet, two stories, 40 feet high;
Group M less than 4,800 square feet, one story, 40 feet high; Group S-1 less than 4,200 square feet, one story, 40 feet high;Group S-2 less than 7,200 square feet, two stories, 40 feet high;Group R-3 as permitted in the building subcode and including accessory private garages, radio and television antennae and swimming pools;
Group R-5 as permitted in the one- and two-family dwelling subcode and including accessory private garages, radio and television antennae and swimming pools.

Remember that Hell for Architects and Engineers is to work on thier own designs for eternity.


 

iwire

Moderator
Staff member
Location
Massachusetts
I think it is important to remember that electrical contractors and architects / engineers have different goals and priorities.

In a general sense ECs are always looking to provide just enough to make the customer smile while at the same time maximize their own profits.

On the other hand when a customer hires an architect, or more so an engineer in my opinion that is the customer saying ...

'I need help, I don't want code minimums, I want something that works today and into the future'.

That being the case it makes sense that the architects and engineers specify more than the code minimums.
 

jbelectric777

Senior Member
Location
NJ/PA
No Dennis, no additional load planned at all, it just seems like a waste of money when you look in a 200A panel and see 100 amp feeder conductors, and Rick is right about the limitations of the contractors legal design limits. NJ has a very large book (The blue book ) called the NJUCC NJAC Administrative code and to be honest I have not seen anything like it anywhere in the bordering states, I think they just adopt the NEC when they feel like it. Like when PA was enforcing AFCI protection, NJ was not, and when the 2008 code called for the "at least one communication outlet" NJ did not require it. The worst part about is everymonth ya get changes, additions and revisions and you have to actually remove old and replace them with what they send in the mail. My good freind Tom Pernal said it best "Its the biggest waste of time and paper he's ever seen" they could be putting it on discs (CD's) If you work for a town its free, its 40 or 50 bucks for the subscription if you dont work for a town. The nicest part about the NJDCA is the continuing education is free and goes toward your contractors license if you want. Not sure on the 10 hr course tho because Im not renewing my contractor just my inspector. HHS
 

stew

Senior Member
with 100 amp feeders I assume the service disconnects are ahead of the panels. The reason for 200 amp panels could simply be cost. I can purchase a 20/40 siemans for less than a 100 12/24. In fact that is exactly what I am doing on some apt retrofits that have 150 amp Federal Pacific panels.I use the 20 40 200 because the cost is considerably less.
 
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