Closed Delta 120/240V 3-phase service

obviously very different practices on different sides of the pond. Virtually all residential distribution over here is 3 phase. The only time I've ever spotted single phase is when an isolated property has its own transformer.

I just wish I had three-phase into my house.

On Wed, 20 Feb 2008 04:56:19 +0000 (UTC) Dave Martindale wrote: | krw writes: | |>Look again (open your eyes this time). You're not seeing the forest |>for the trees. It *IS* on top of 90% of the poles in the country. |>The other 10% are single phase only, generally found only in rural |>areas. | | Really? In all of the places I've lived, residential areas had | single-phase service only: a single MV line running down the top of the | poles along the street or alley, and single-phase transformers | providing center-tapped 120/240 service to several houses per | transformer. Three-phase distribution is used for large customers | only. Given the amount of area covered by single-family houses | compared to the area used by commercial/industrial/large residential | (high rise), I'd have to guess that more than 50% of the total number | of poles that have any transformers carry one single-phase | transformer.

Around here there are many areas where three phase distribution exists passing by residential locations. The residential dwellings still get just single phase. Many businesses, like restaurants, get three phase service. There are three transformers. But they get 208Y/120. There is no 240 volts in that. Some legacy services for older places do have

On Wed, 20 Feb 2008 09:34:13 +0000 (GMT) charles wrote: | In article , | Dave Martindale wrote: |> krw writes: | |> >Look again (open your eyes this time). You're not seeing the forest |> >for the trees. It *IS* on top of 90% of the poles in the country. |> >The other 10% are single phase only, generally found only in rural |> >areas. | |> Really? In all of the places I've lived, residential areas had |> single-phase service only: a single MV line running down the top of the |> poles along the street or alley, and single-phase transformers |> providing center-tapped 120/240 service to several houses per |> transformer. Three-phase distribution is used for large customers |> only. Given the amount of area covered by single-family houses |> compared to the area used by commercial/industrial/large residential |> (high rise), I'd have to guess that more than 50% of the total number |> of poles that have any transformers carry one single-phase |> transformer. | | obviously very different practices on different sides of the pond. | Virtually all residential distribution over here is 3 phase. The only time | I've ever spotted single phase is when an isolated property has its own | transformer.

But homes in UK generally only get one phase at 240 volts. Some parts of the world, though, do typically provide three phase to a home, making 380,

true, most homes only have a single phase (although I have all 3) but the local distribution is 3 phase.

On Wed, 20 Feb 2008 22:36:36 +0000 (GMT) charles wrote: | In article , | wrote: |> On Wed, 20 Feb 2008 09:34:13 +0000 (GMT) charles wrote: |> | In article , |> | Dave Martindale wrote: |> |> krw writes: |> | |> |> >Look again (open your eyes this time). You're not seeing the forest |> |> >for the trees. It *IS* on top of 90% of the poles in the country. |> |> >The other 10% are single phase only, generally found only in rural |> |> >areas. |> | |> |> Really? In all of the places I've lived, residential areas had |> |> single-phase service only: a single MV line running down the top of the |> |> poles along the street or alley, and single-phase transformers |> |> providing center-tapped 120/240 service to several houses per |> |> transformer. Three-phase distribution is used for large customers |> |> only. Given the amount of area covered by single-family houses |> |> compared to the area used by commercial/industrial/large residential |> |> (high rise), I'd have to guess that more than 50% of the total number |> |> of poles that have any transformers carry one single-phase |> |> transformer. |> | |> | obviously very different practices on different sides of the pond. |> | Virtually all residential distribution over here is 3 phase. The only |> | time I've ever spotted single phase is when an isolated property has |> | its own transformer. | |> But homes in UK generally only get one phase at 240 volts. Some parts of |> the world, though, do typically provide three phase to a home, making 380, |> 400, or 415 volts available. | | true, most homes only have a single phase (although I have all 3) but the | local distribution is 3 phase.

But the only three phase system you can get is a star (what is referred to as "wye" in the USA). You can't get delta. And you can't get "6 star" (as I call it) nor would you have any reason to need it (because no appliances would ever assume 480 volts on a single split phase system). Do don't have the voltage assumption issue the USA has.

Really!

Where do you live, Mongolia? The only places I've seen single phase distribution is in the middle of the country (rural Vermont, in fact).

Bullshit!

Your *guess* is wrong.

Different issue. My father wanted three phase into his house in the late '50s. He argued that it was on top of the pole already so it was a simple matter to bring it down to the entrance panel. They told him that they would do it if he guaranteed a $100/month bill (rather steep for the '50s).

Currently, the area around Vancouver BC. Other residential areas with single-phase service: near Waterloo, Toronto, and St. Catharines Ontario, near Montreal Quebec.

Where do you live that has full three-phase MV on top of every pole on every street in a residential area? And three transformers on every pole that has a transformer?

Not where I live now, nor where I've lived for decades. Again, where do you live that has 3-phase on the pole outside every house?

Dave

The transformers aren't on every pole (every third), but the wires are. I see it all over. All you have to do is look.

Everywhere I've lived (some underground).

----------------- There are many places where a single phase is run down an alley (the next alley is on another phase so that the total district load is pretty well balanced across the 3 phases. This is true in residential districts in many cities which exceed 1,000,000 inhabitants. Simply a matter of economics in situations where high heating or, more likely, cooling electrical demands are not present. Where I am, a 3 phase main feeder is across the street but a single phase feed from this line serves the whole of a small subdivision. There is simply no need for running 3 phases (particularly underground) as loads don't warrant it in this case. In a previous home, 3 phase was down the alley but only because there was a commercial load at the end of the street which warranted the 3 phase feeder.

There is no "one size fits all" solution so no BS is involved-just different observations in different places.

Even the purely residential area I grew up in had all three phases on the pole (one pig per pole - four houses per pole).

Everywhere I've looked but *very* rural areas has three phase distribution.

On Wed, 20 Feb 2008 19:37:38 -0500 krw wrote: | In article , | SW snipped-for-privacy@dsl.pipex.com says... |> In article , |> charles wrote: |> > obviously very different practices on different sides of the pond. |> > Virtually all residential distribution over here is 3 phase. The only |> > time I've ever spotted single phase is when an isolated property has its |> > own transformer. |> |> I just wish I had three-phase into my house. | | Different issue. My father wanted three phase into his house in the | late '50s. He argued that it was on top of the pole already so it | was a simple matter to bring it down to the entrance panel. They | told him that they would do it if he guaranteed a $100/month bill | (rather steep for the '50s).

There is, afterall, a cost to keep 2 more pole pigs up there. Those things are not cheap.

On Wed, 20 Feb 2008 19:37:37 -0500 krw wrote: | In article , snipped-for-privacy@cs.ubc.ca says... |> krw writes: |> |> >Look again (open your eyes this time). You're not seeing the forest |> >for the trees. It *IS* on top of 90% of the poles in the country. |> >The other 10% are single phase only, generally found only in rural |> >areas. |> |> Really? | | Really! | |> In all of the places I've lived, residential areas had |> single-phase service only: a single MV line running down the top of the |> poles along the street or alley, and single-phase transformers |> providing center-tapped 120/240 service to several houses per |> transformer. | | Where do you live, Mongolia? The only places I've seen single phase | distribution is in the middle of the country (rural Vermont, in | fact).

MV comes out of substations in three phase. The distribution trunks are three phase. But many side branches, particularly residential areas, are single phase MV. So everyone on the same street is on the same phase. Big deal. The utility saves money doing that and can keep things in balance by putting the next street on a different phase.

|> Three-phase distribution is used for large customers |> only. | | Bullshit!

Of course in the distribution design, three phase goes all over the place because there might be scattered need for three phase. And then they have to keep it reasonably balanced where it does go, so the single phase lines branching off or going to a direct service are balanced over these phases.

|> Given the amount of area covered by single-family houses |> compared to the area used by commercial/industrial/large residential |> (high rise), I'd have to guess that more than 50% of the total number |> of poles that have any transformers carry one single-phase |> transformer. | | Your *guess* is wrong.

Actually this is quite common. Even if three phase distribution goes through a residential area, the transformers on the poles for homes along the way are usually just one transformer supplying one phase to that bunch of homes.

On Wed, 20 Feb 2008 20:18:45 -0500 krw wrote: | In article , snipped-for-privacy@cs.ubc.ca says... |> krw writes: |> |> >> In all of the places I've lived, residential areas had |> >> single-phase service only: a single MV line running down the top of the |> >> poles along the street or alley, and single-phase transformers |> >> providing center-tapped 120/240 service to several houses per |> >> transformer. |> |> >Where do you live, Mongolia? The only places I've seen single phase |> >distribution is in the middle of the country (rural Vermont, in |> >fact). |> |> Currently, the area around Vancouver BC. Other residential areas with |> single-phase service: near Waterloo, Toronto, and St. Catharines |> Ontario, near Montreal Quebec. |> |> Where do you live that has full three-phase MV on top of every pole on |> every street in a residential area? And three transformers on every |> pole that has a transformer? | | The transformers aren't on every pole (every third), but the wires | are. I see it all over. All you have to do is look.

There are lots of distribution lines with all three phases. There are also lots with just one phase. Either way, just one transformer is the norm for residential services.

|> >> Given the amount of area covered by single-family houses |> >> compared to the area used by commercial/industrial/large residential |> >> (high rise), I'd have to guess that more than 50% of the total number |> >> of poles that have any transformers carry one single-phase |> >> transformer. |> |> >Your *guess* is wrong. |> |> Not where I live now, nor where I've lived for decades. Again, where do |> you live that has 3-phase on the pole outside every house? | | Everywhere I've lived (some underground).

You manage to only live in strange places.

| Even the purely residential area I grew up in had all three phases | on the pole (one pig per pole - four houses per pole).

One house I lived in a long time ago had only single phase MV on it. Another around the corner (after we moved) had three phase MV on it. One pole pig served 3 homes single phase. The three phase then ran on down the street and branched off to a school which had three very large pole pigs. I went to grade school there and by 5th grade knew that was for three phase power (but I didn't yet know the difference between delta and wye).

Where I live now has a single phase MV branch running down about 6 poles and then goes underground to serve 3 pad mounts. It comes off a three phase MV trunk that goes to a college about 4 miles north.

If I wanted three phase power here, it would be VERY expensive to get.

Different utilities in different areas have different practices, including the willingness to bring three phase down a street that doesn't need it yet, or will never need it.

I grew up in a large subdivision. Three phase went in at 3 points, but all the streets not on the roads the three phase followed were fed single phase. The single phase loads were approximately balanced, but some of them were not trivial. One single phase fed my longish street plus 3 shorter streets, a total of 9-10 pole pigs with 5-6 houses per transformer. There was a single three phase load, a clubhouse/golf course.

I *have* looked where I live. I've told you what I see (a single MV wire on the top of the vast majority of poles in residential areas). The next level up the distribution hierarchy is 3-phase, so 3-phase lines do pass through residential areas, but only one phase is tapped for the line of poles down each street or alley.

Again, where do you see 3-phase on every pole? Tell us some places. Even when there are 3 phases, do the transformers occur in groups of 3? Or do you mostly get one transformer per pole, tapping only one of the

And where would that be? City or suburbs?

Dave

Good grief, Phil! Read! It's not distribution, rather service! The three secondary phases *ARE* on the poles.

Nope, Midwest, Northeast/New England, but I see it everywhere.