Any help Please service calculations...

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pauls371

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West Palm Beach Florida
Im working on a job and trying to size the service and feeders for a 6 unit apartment building. The building contains 6 apartments around 1400 sq feet of living space per apartment. Also 6 garages. 208 volt.Im a bit new as to a service of this size but have come up with using code 220.84 Units all have 50 amp stove and 30 amp A/C units


If i apply code 220.84 (C)-1 3 VA for all lighting and all outlets per sq ft 45,000 VA

add in 1500 VA for each 2 wire circuit for appliances. 54,000 VA ....about 6 per apartment

Nameplates of AC units 21,600 VA

Electric stoves at name plate 62,000 VA

i come up with 878 amps

Code says use table 220.84 and for 6 to 7 dwelling units my demand factor percent should be 44%
equals 386 amps
I SHOULD BE GOOD WITH 400 AMP SERVICE i think????

Please if you are familiar could you please review and let me know any thoughts you might have.
 
Re: Any help Please service calculations...

Thanks for your response. Yes you are right im might be a bit off let me re add up the appliance circuits.
1 dishwasher 1500 va
2 garbage disposal 1500 va
3 fridge 1500 va
4 circut for kitchen counter 1500 va
5 circut for kitchen counter 1500 va
6 Laundry dryer 1500 va
7 washer 1500 va
8 hot water 1500 va

Adjust to 12,000 VA

Thanks for your help.
 
Re: Any help Please service calculations...

Paul, never hurts to lay "ALL THE CARDS" on the table,when asking for help...

[ January 17, 2005, 09:50 PM: Message edited by: dillon3c ]
 
Re: Any help Please service calculations...

#6 and #7 are the same load, no need to add the washer as it is apart of the laundry circuit. The refrigerator, #3 also does not need to be included in the calculation.
 
Re: Any help Please service calculations...

I've never studied the optional method--I'm getting the impression from 220.82(B) that dryers don't need to be calculated at a minimum of 5000 VA for this method?
 
Re: Any help Please service calculations...

Originally posted by pauls371:
The building contains 6 apartments around 1400 sq feet of living space per apartment. Also 6 garages. --> 208 volt .<---
Click to expand...
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I'm a "lil unsure as to what kind of service we are applying. As in the forumula of (1.732) ?
 
Re: Any help Please service calculations...

Originally posted by pauls371:
Should i expect the voltage to be 120/240 volt as its a residential unit?
Click to expand...
Not necessarily, it is very possible the service is 208y/120 for a Multiple unit bldg.

Roger
 
Re: Any help Please service calculations...

What exactly is your role in this project? The voltage you may find out from your local utility if you are coming off of one of their transformers. This is a vital piece of information in figuring out your service size.
 
Re: Any help Please service calculations...

Paul, I would "think only single phase loads" would be served.At any rate,I've seen a 3 phase service applied to a 2600' brick rancher dwelling in Dallas,Texas years ago.(never knew why)..At any rate,have applied #'bers, think 400 ampere service,(4-40 watt bulbs)that you will not exceed..As far as garage space,not generally figured into "Dwelling unit load"..You have stated "around" 1400' in apartments.Also are you sure about the dryers at 1500 on nameplate?I have run three differant calculations,in following your post.Might not be a bad idea to wait to be addressed by a moderator in your application,in the end result.
 
Re: Any help Please service calculations...

My role n the job is design and build. I am the contractor doing the job. Im am told now that system will be single phase 240 volt. Thanks for your help guys...
 
Re: Any help Please service calculations...

At 240V, I have you over 400Amps. Approx 450 using the standard and 500 using the optional.
 
Re: Any help Please service calculations...

Mr. bwyllie sir,in your standard method,got the same.Your optional,I come up with a differant number..Under 400 amps
 
Re: Any help Please service calculations...

Mr. harborrick, Mr.bwyllie,Ok I'll bite,lets see your #'ber's...
 
Re: Any help Please service calculations...

I actually stand corrected, I believe a 400A service at 240V, single-phase would be ok. On the standard method I had a total of 121.8KVA, a demand of 80.1 and an amperage of 333A and the optional method total of 162.6, demand of 71.5 and an amperage of 298A.
 
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