I don't know about your area...but here all upgrades, 200 amp and larger, must first be cleared with the PoCo. Ultimately, it is they who decide what 'flavor' of electric you get, and whether it will cost you extra.
#97592 - 03/05/0601:57 AMRe: Larger than 400 amp service - residential
I seen a few 600 amp services around here. All in new construction. I never checked the load or did a calc. but I don't think they really are drawing that much. They may be in the 10K-15K sf range. The 400 amp big homes around here seem to be drawing around 30 amps during the day. I sure it's much more with a party at night but I doubt they are over 200 amps.
For our utility getting them to upgrade anything is difficult. Even if you get a larger service drop is the trasformer up to the task? Will they change that also? Around here they probibly would not.
Some areas they tear down or rebuild homes that once had 60-100 amp services one at a time. In the place they put big homes with 400 amp. But the utility still has the small transformers causing lights to flicker with loads.
3 Phase may not be permited for homes by the utility or be available.
#97595 - 03/05/0611:53 AMRe: Larger than 400 amp service - residential
First of all, the equipment used for a 400 amp service is, as the PoCo considers it, really only for a 360 amp service. If the calculated load is higher than 320 amps, they will want to replace the CT used to meter the power consumption with one of a higher rating.
Likewise, they will also look at their transformers; it is quite possible that the transformers are already being used at capacity, and will have to be replaced.
Just a few months ago, I was in this situation with our PoCo. The Troubleman raised his concerns, and a two-hour shut-down became a five-day shut-down. On Day 5, I had at least six levels of PoCo management decend on the jobsite; their "top dog," after reviewing the site, got all wound up, and started to give his standard speach to me about "you guys who don't clear things with us." He looked truly disappointed when I produced the paper where the PoCo had, in fact, signed off on the job!
[This message has been edited by renosteinke (edited 03-05-2006).]
#97597 - 03/05/0605:12 PMRe: Larger than 400 amp service - residential
A residential customer wanted to update her 60 amp 120/240 volt service to a 200 amp service. The PoCo's distribution voltage was 480 volt. (In Seattle's University district) They told me she would have to install a transformer pad in the back yard which would have eliminated the parking space. I talked them into a 100 amp 480 volt single phase service and we installed a dry type 480/120/240 volt transformer in the basement.
#97598 - 03/05/0605:41 PMRe: Larger than 400 amp service - residential
The great thing about this site is still the things you learn.
277/480 volt to a resi job??? Never thought that could happen!!
'Round here.....'400' resi is really 320 continuous 'by the book'. Yes, we have the famous McMansions; some at 200, some at 400. A few customs....full 400 (CT job) to 2x200 mcb panels; some 400A MCB to 3x150 MCB panels. Had a 600 amp, 120/208, 3 phase, in 1 a while back; full blown 600, ct's etc.
As Tom said above, the reality load is usually nowhere near the calc load, or rating of the MCB.
As to our POCO, provide the required data & calcs to marketing; get a reply; meet with the wiring inspector and/or engineering; & you're home free. The drop/feeder/xfr is their responsibility. Costs are now charged to the client, since the great deregulation passage.
#97599 - 03/07/0606:44 PMRe: Larger than 400 amp service - residential
I'm preparing to upgrade a residence from 320A to 1200A single phase! 8500 sq.ft. existing home with the 320A service is having an 11500 sq.ft. addition which will be total electric. 80kw of heat and 16 ton of A/C. Gymnasium, indoor pool, outdoor pool, endless wave pool, 5 car garage, gameroom, etc. The existing 8500 sq.ft. utilizes natural gas heating and appliances. When I talked to the PoCo engineer about all of this he just looked at me and said, "I thought each lot in this addition would just have one house on them". We need a bigger tranny.