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#61274 - 01/20/06 08:29 PM Residential 3 Phase, Why / Why Not?
NORCAL Offline
Member

Registered: 09/25/02
Posts: 807
I have a question,why not provide homes with 3 phase power? With energy conservation being a "hot subject" it seems to be a tremendous waste to have single phase air conditioning equipment in most of the new homes constructed.

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#61275 - 01/20/06 08:44 PM Re: Residential 3 Phase, Why / Why Not?
mxslick Offline
Member

Registered: 10/24/04
Posts: 785
Loc: Atomic City, ID USA
One word: MONEY

From the POCO end: Extra transformers, 4-wire service drops, three-phase metering, and in a lot (most?) of the residential areas, lack of three-phase primarys. (And let's not get into the whole open-delta thing, please.)

From the homebuilder's end: Increased cost for the 3-phase panel and main breakers. Increased cost to wire up the appliances.

But it would be more efficient, agreed.
_________________________
Stupid should be painful.

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#61276 - 01/20/06 09:34 PM Re: Residential 3 Phase, Why / Why Not?
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9045
Loc: Estero,Fl,usa
I suppose there might be a buck or two to save in a big McMansion but most houses would be better served by simply using better glass and more insulation. The new HVAC systems are really pretty efficient.
Other than pool pumps I doubt there is much else that would benefit from 3 phase.
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Greg Fretwell

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#61277 - 01/20/06 10:52 PM Re: Residential 3 Phase, Why / Why Not?
wa2ise Offline
Member

Registered: 11/29/02
Posts: 771
Loc: Oradell NJ USA
In my home town (Oradell NJ) there's several late 50's houses fed with 3 phase power (normal 120/240 with an open delta 240v). Must have been the first houses with central air. Presumidly the homeowners have never mistaken the 208V line for 120V.

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#61278 - 01/20/06 10:54 PM Re: Residential 3 Phase, Why / Why Not?
SolarPowered Offline
Member

Registered: 07/05/04
Posts: 615
Loc: Palo Alto, CA, USA
I was unaware that there is a big difference in efficiency between single-phase and three-phase air-conditioning equipment. Just how big is the difference?

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#61279 - 01/21/06 12:40 AM Re: Residential 3 Phase, Why / Why Not?
ShockMe77 Offline
Member

Registered: 06/11/05
Posts: 823
Loc: Rahway, New Jersey
In my 15 years, I have worked in exactly 1 residential home that had 3 phase power to it. The owner was filthy rich. All the HVAC equipment is also 3 phase, and even some kitchen appliances. The pool in the basement may also be powered by 3 phase equip but I'm not sure about that. Yes, a pool in the basement, nice, huh?

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#61280 - 01/21/06 02:27 AM Re: Residential 3 Phase, Why / Why Not?
Alan Belson Offline
Member

Registered: 03/23/05
Posts: 1801
Loc: Mayenne N. France
Latest technology for AirCon is to use dc motors & inverters to give infinitely variable compressors and evaporators and 'soft start'. Coupled with microprocessor control and ozone-friendly refrigerant, [R410A] these units easily achieve COPs of well over 4, so that the difference between 3 and single phase operation is nil.
www.toshiba-aircon.co.uk

[Link gives a good idea on wassappenin',
technology wise, I'm not saying they're better than others.]

Having seen neighbors juggling their demand between phases and continually tripping breakers when they plug their kettle into the 'wrong' recep., I'd say 3 phase and residential is a bad idea.

Alan



[This message has been edited by Alan Belson (edited 01-21-2006).]
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#61281 - 01/21/06 04:38 AM Re: Residential 3 Phase, Why / Why Not?
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
3-phase domestic supplies are pretty common in Continental Europe, although not here in the U.K.

So many of those supplies are very low rated though, sometimes set for only 15 or 20A per phase. As Alan says, you have to juggle what to Americans and Brits seem like small loads just to avoid tripping a main breaker.

Somehow I can't imagine that being a problem if 3-phase were used in U.S. homes, as the services would be "a little" heftier.

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#61282 - 01/21/06 04:47 AM Re: Residential 3 Phase, Why / Why Not?
iwire Offline
Moderator

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
 Quote:
I have a question,why not provide homes with 3 phase power? With energy conservation being a "hot subject" it seems to be a tremendous waste to have single phase air conditioning equipment in most of the new homes constructed.


Watts are watts regardless of them being delivered three phase or single phase.

746 watts per HP is unchanging.

Advantages of three phase are smaller conductors.

Disadvantages...cost.

Any three phase distribution equipment costs more than the equivalent single phase equipment.
_________________________
Bob Badger
Construction & Maintenance Electrician
Massachusetts

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#61283 - 01/21/06 06:26 AM Re: Residential 3 Phase, Why / Why Not?
WFO Offline
Member

Registered: 09/03/05
Posts: 206
Loc: Cat Spring, TX
We had one home on our system that had a true 3 phase service.
Someone had convinced this guy that 3 phase was cheaper than single phase. (Still haven't ever gotten a good explanation on why people think that .

Anyway, after living there a couple of years, he decided his bill was too high and had the entire house converted back to single phase. (More cost for no significant return).

This guy was singularly lacking in wit or tack, so the fun part was during the conversion when they installed the single phase equipment before we had changed out his delta bank. The AC guy hooked the controls up to the 208 high leg and fried the AC.

Of course, Mr. "I've got more dollars than sense" wanted us, the POCO, to pay for it.

We just smiled


[This message has been edited by WFO (edited 01-21-2006).]

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