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Called the electrical company about upgrading my service to 200 ampres. The operator on the phone asked if I wanted 3 phase or single phase. I told her single phase, and she said that 3 phase was available where I was at. I thought it sounded far-fetched, but I looked out the window, and yep, there's three high-side wires up on the pole! Most likely for the school across the street.

Now, my ultimate question is are there any appliances that I can get for the home that will run on 3-phase? HVAC equipment is supposed to be much more efficient. How much savings would I get by running a 3-phase heat pump over a single phase? I am looking at upgrading that this summer. Howabout any other appliances?
 

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I have 120/208 3ø at my house. Have had it for 14 years.

These days, there's not much difference in efficiency of a single phase A/C unit vs. 3ø. They are however, much more reliable. Other stuff, like well pumps, etc. are about 5 - 10% more efficient 3ø. And if you have any type of shop equipment in the garage, used 3ø stuff is usually cheaper to buy. New stuff, not so much.

The panel will be a bit more expensive, but a 150 amp 3ø service has more power available than a 200 amp single phase one.

240 volt stuff, like dryers and ranges will work fine on 208, but with less heat. They will last much longer though.

If the service is 240 delta, it has a high leg. This phase is 208 to neutral, and is useless for anything other than 3ø loads and 240 loads that don't use the neutral (like a water heater). The other two phases are the same as a single phase system.

If it were me, I'd get the 3ø service. But I'm also a professional electrician who understands 3ø systems, plus I have a bunch of 3ø shop equipment.

Rob
 

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I have three phase as well one in Wisconsin and also in France as well.

In Wisconsin typically the resdential will get either 208Y120 or 240D120 ( this part is no longer can get it for new customers )

But one instering part with my three phase service is that I can get 480Y277 due I do have commercal property next to it so it was a no brainer to get that voltage so I end up just have one service drop that it ( the house get 208Y120 thru the transfomer to feed the house only )

However over here in France the typical voltage I get on three phase is 415Y240 volts which it is pretty common over here and with larger services it automatique have to use three phase once you get over 160 amp service size or larger. ( the smaller service can have a choice of single phase or three phase and the single phase is 240 volt line to netural )

Merci,
Marc
 

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With the three primary (high side) lines at the top of the utility pole you have 3 phase power on the street but you still need a 3 phase transformer or transformer array on the pole to give you 3 phase (usually 120/208 wye) at your house.

The 3 phase transformer(s) may already be there to serve the school but if not, you may have to pay extra to have them installed. Inquire about the costs before making your final selection.
 

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Now, my ultimate question is are there any appliances that I can get for the home that will run on 3-phase?
NONE. Well, nothing that a normal home would use.


HVAC equipment is supposed to be much more efficient. How much savings would I get by running a 3-phase heat pump over a single phase? I am looking at upgrading that this summer. Howabout any other appliances?
3-phase is a bit more efficient, but nothing you'll ever actually notice on a bill.

I can guaranty you this, you will NEVER see a ROI on installing 3-phase to a home as an upgrade.
The only reason for having it would be if you had really big equipment that required it. Or, MANY pieces of equipment.
Besides, I would bet you'd likely be billed commercial once they brought it to your house.
 

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NONE. Well, nothing that a normal home would use.


3-phase is a bit more efficient, but nothing you'll ever actually notice on a bill.

I can guaranty you this, you will NEVER see a ROI on installing 3-phase to a home as an upgrade.
The only reason for having it would be if you had really big equipment that required it. Or, MANY pieces of equipment.
Besides, I would bet you'd likely be billed commercial once they brought it to your house.
I agree with Speedy Pete just trust me I have three phase service at Wisconsin and I do get billed in commercal rates due it have incomming service on commeral side but the rate between the two is not really huge at all.

But if you have both single and three phase service there will be no question asked a very good chance you will billed higher rate or dual service cost.

Merci.
Marc
 

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NONE. Well, nothing that a normal home would use.


3-phase is a bit more efficient, but nothing you'll ever actually notice on a bill.

I can guaranty you this, you will NEVER see a ROI on installing 3-phase to a home as an upgrade.
The only reason for having it would be if you had really big equipment that required it. Or, MANY pieces of equipment.
Besides, I would bet you'd likely be billed commercial once they brought it to your house.
This is true, if 3ø costs much of anything, you'll never live long enough to recoup the investment with a basic average house. About the only thing that would use 3ø here would be the A/C, and these days there's not much difference in efficiency. But 3ø units are more reliable.

Around here some of the subdivisions built in the 70s had 3ø to a lot of houses. They all had 240 delta services and the only load served by all 3 phases was the A/C. Back then there was quite a difference in efficiency, plus the 3ø units were far more reliable. Some of them are still in operation.

If you have a well, I'd highly advise using 3ø. 3ø Well pumps are more efficient, but the real seller here is that they seem to run forever with no problems. No start relays, no capacitors, just a simple contactor and overloads. Though some of us will install a phase failure relay, this insures that all 3 phases are valid before the motor starts.

Edit to add;

The 3ø I have at my house is billed at the same rate as single phase would be. If I remember (it's been 14 years....), single phase would have cost $1700, and 120/208 wye cost $3600. With all the 3ø stuff I have, phase conversion would have been slightly less than the difference, but I've more than made up for it in efficiency. With all the shop equipment, I have 22 3ø motors.
 

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This is true, if 3ø costs much of anything, you'll never live long enough to recoup the investment with a basic average house. About the only thing that would use 3ø here would be the A/C, and these days there's not much difference in efficiency. But 3ø units are more reliable.

Around here some of the subdivisions built in the 70s had 3ø to a lot of houses. They all had 240 delta services and the only load served by all 3 phases was the A/C. Back then there was quite a difference in efficiency, plus the 3ø units were far more reliable. Some of them are still in operation.

If you have a well, I'd highly advise using 3ø. 3ø Well pumps are more efficient, but the real seller here is that they seem to run forever with no problems. No start relays, no capacitors, just a simple contactor and overloads. Though some of us will install a phase failure relay, this insures that all 3 phases are valid before the motor starts.

Edit to add;

The 3ø I have at my house is billed at the same rate as singly phase would be. If I remember (it's been 14 years....), single phase would have cost $1700, and 120/208 wye cost $3600. With all the 3ø stuff I have, phase conversion would have been slightly less than the difference, but I've more than made up for it in efficiency. With all the shop equipment, I have 22 3ø motors.
That one reason why I need three phase in first place due I have deep well ( it is over 200 meters down < about 660 feet > ) and have 15 CV pump to over come the head pressure with 1.5 inch discharge port. also I have emeregcy well which it is dual driven ( either electric or diesel unit on pto ) which it been used by Pomiers ( Fire dept ) from time to time.

Merci,
Marc
 

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That one reason why I need three phase in first place due I have deep well ( it is over 200 meters down < about 660 feet > ) and have 15 CV pump to over come the head pressure with 1.5 inch discharge port. also I have emeregcy well which it is dual driven ( either electric or diesel unit on pto ) which it been used by Pomiers ( Fire dept ) from time to time.

Merci,
Marc
I'm lucky, my well is only 140' deep. 1.5HP pump. I just went out and looked; it has been run 2608 hours, and has started and stopped 91,576 times.
 

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I'm lucky, my well is only 140' deep. 1.5HP pump. I just went out and looked; it has been run 2608 hours, and has started and stopped 91,576 times.
I don't think any of single phase motours will last that long of number of start et stop cycle.

IIRC most uselly go out anywhere from 2,000 to 50,000 cycles depending on design of the motour and starting system.

I just texted my sister in wisconsin and she reply what my pump hours now it is at 5437 hours but I do not know how many start et stops but for pomiers that differnt story IIRC about 470 hours ( it have 6 inch discharge port so that why it can fill the tanker pretty fast )

Merci,
Marc
 

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3 phase well pumps and VFD are very common now a days, people that live in the city and have a second home in the country do not like the water pressure change, so they generally get a VFD installed to accommodate this issue. I've yet to come across a house that would benefit from a 3 phase service, and doubt I ever will.
 

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Edit to add;

The 3ø I have at my house is billed at the same rate as single phase would be. If I remember (it's been 14 years....), single phase would have cost $1700, and 120/208 wye cost $3600. With all the 3ø stuff I have, phase conversion would have been slightly less than the difference, but I've more than made up for it in efficiency. With all the shop equipment, I have 22 3ø motors.
I don't understand; could you show the calculations?

Around here some of the subdivisions built in the 70s had 3ø to a lot of houses. They all had 240 delta services and the only load served by all 3 phases was the A/C. Back then there was quite a difference in efficiency, plus the 3ø units were far more reliable. Some of them are still in operation. .
I could see an apartment building where 120/240 delta 3 phase was available and all of the apartments were wired to balance any 240 volt only single phase loads using the B phase (high leg) leaving more of the A and C legs for the 120 volt loads. For a subdivision, another pole transformer is needed every 300 feet or so to avoid voltage drop issues so if there were no 3 phase loads then they would probably not have 3 phase service to the homes.
 

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Apartment buildings are usually 120/208.
 

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I don't understand; could you show the calculations?


I could see an apartment building where 120/240 delta 3 phase was available and all of the apartments were wired to balance any 240 volt only single phase loads using the B phase (high leg) leaving more of the A and C legs for the 120 volt loads. For a subdivision, another pole transformer is needed every 300 feet or so to avoid voltage drop issues so if there were no 3 phase loads then they would probably not have 3 phase service to the homes.
If the service has 3 hots and a neutral/ground going into the weatherhead, it's 3ø. If one of the hots is smaller than the other two, it's a ∆. Most of these residential 3ø services have a delta breaker in the panel. This is a 3 pole breaker that has 4 terminations. Basically a 2 pole breaker with a 3rd pole added on, and the 3rd pole has lugs for both in and out. The high leg goes into a lug on the breaker; the other two legs are fed normally. The result is all 3 phases on the load lugs.

I've seen quite a few apartments with 3ø services, but every one of them had a 120/208 wye. Each unit had a single phase panel fed by two legs of the wye system.

I've also seen motels that had through-the-wall- HVAC units that operated on 20 amp 250 volt receptacles and the service was 240∆. The high leg and one of the other legs was used for the receptacles.

I wouldn't recommend connecting a residential stove or oven using the high leg of a ∆ service. Most of these appliances need 120 for the controls. VERY few resi electricians know anything about a ∆ service, and even fewer handyman types do. There'd be a 50/50 chance of getting the high leg on the control circuit, thus burning it up. Water heaters, baseboard heaters, receptacles that don't involve the neutral are all perfectly fine with the high leg, but not much else.

Rob
 

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I live in a mid-century neighborhood in Phoenix, and many of these houses had 3-phase back in the 50's-70's for air conditioning. Most have had service/panel changes since, and there are no longer any 3-phase customers on my street. The high-leg open delta transformer is still there (with the primary fuse in, wasting power). I just built a detached shop and had planned on getting 3-phase service for it, and then feeding the house as a single-phase subpanel from that service. It would have cost about $3000 more than just running a 100A single phase feeder from the house, so I didn't do it. With VFD's being relatively cheap these days and providing an added benefit of electronic control, it's hardly justifiable to run 3-phase for a small shop.
 

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Yes, VFDs have become sort of the norm for single to 3ø power conversion. But they have some disadvantages as well.

1) A VFD will run only 3ø loads, no single phase stuff, like control transformers, starter coils, pilot lights, etc.

2) The first time that a switch between the VFD and motor is opened under operation will very likely be the last time for the VFD.

3) Unless the VFD is grossly oversized, there's very little overload capacity. A 3ø motor operating on line power will have a maximum torque anywhere from 200% to 400% of running torque. On a VFD, it's more like about 150%

4) Generally speaking, more than one 3ø motor means more than one VFD. The cost can add up quickly.

5) Unless a line reactor is installed, a VFD will send harmonics back into the power line. While not usually a problem, if the incoming line is fairly high impedance, the harmonics can wreak havoc with other electronic devices.

When I built my house, VFDs weren't very reliable, and very few (if any) would accept single phase input power. They were also rather spendy. Phase converters were about the only way to go back then. Their efficiency is not very good, plus they're somewhat rough on motors.
 

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You're absolutely right on the overload issue with VFDs. They do not handle sudden large mechanical loads on the motor very well. The other problems are solvable when you consider that using a VFD to run 3-phase equipment on single phase power is basically the same wiring the machine for a single phase motor replacement. All the control circuits, etc. need to be rewired, and there should be nothing between the VFD and the motor. It is a pain, and a large shop would require many VFDs. But you get the benefit of variable speed for everything, which may or may not be useful depending on the equipment.
 
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