high-leg (or wild-leg

[tom baker]

Our POCO no longer supplies mid point grounded delta transformers. But they are still very common.
On the primary, its has two hots and a neutral. So less expensive for POCO. Often will find the panel with two breakers and a space...all the way down.
They tend to have voltage imbalance problems.
Many electricians have never seen a mid point grounded delta.

 

[kwired]

While true on a 480 4 wire delta (very rare here in the states), the book link in shamsdebout post clearly is talking about a 240/120 4-wire delta, and even has a diagram to the effect, the way the author describes the circuit he is adding the 120 volts from the center tap to either "A" or "C" phase with the 240 volts between "A or C" and "B" phase, which we know is wrong which should be 120*1.732=208

Not all that rare where I am.

There are a lot of center pivot irrigation systems powered by 480 volt open delta systems. Most POCO's prefer this over corner ground (only one phase greater than 240 to ground) plus the ability to only use two transformers is to their advantage most of the time.

These systems usually only require 30 amps and most of the time even less so it is not a large load for the POCO system and does not require a neutral.

Another reason for them to use two transformers is less load = less revenue from energy sales, so why spend more on a third transformer when two will work.

 

[hurk27]

Not all that rare where I am.

There are a lot of center pivot irrigation systems powered by 480 volt open delta systems. Most POCO's prefer this over corner ground (only one phase greater than 240 to ground) plus the ability to only use two transformers is to their advantage most of the time.

These systems usually only require 30 amps and most of the time even less so it is not a large load for the POCO system and does not require a neutral.

Another reason for them to use two transformers is less load = less revenue from energy sales, so why spend more on a third transformer when two will work.

I'll bet if you count all the other types of services supplying buildings and homes in your area, then count these irrigation systems using the 4-wire delta 240/480 with the 415 high leg, I bet you would find they make up less then 1% of the over all services in your area, to me thats a rare service

 

[kwired]

Can you elaborate on this? Still has X1, X2, and X3 (A, B, and C), so how is it only 2 phases?

The secondary has X1, X2, X3, XO as usual.

The primary only uses H1, H2, HO on an open delta primary transformer bank even if all three phases are present.

If it were a closed delta (with three transformers) then all three primary phases are used plus the primary neutral is also bonded to the secondary XO.

Here is a schematic:


View attachment 4562

 

[kwired]

I'll bet if you count all the other types of services supplying buildings and homes in your area, then count these irrigation systems using the 4-wire delta 240/480 with the 415 high leg, I bet you would find they make up less then 1% of the over all services in your area, to me thats a rare service

If you count in the cities and towns yes.

If you only count the rural systems you may want to bump your 1% up to at least 10% around here.

 

[jim dungar]

Here is a schematic:


View attachment 4562

Notice how your diagram uses (2) phase conductors plus a neutral. This means the source is a 3-phase open wye.

 

[hardworkingstiff]

When did the voltages change?

When did the voltages change?

When I first started in the early '70s, the high-leg was about 190V and now it's about 208V. That equates to 110/220 vs 120/240. When did we go from 110/220 to 120/240?

 

[shamsdebout]

While true on a 480 4 wire delta (very rare here in the states), the book link in shamsdebout post clearly is talking about a 240/120 4-wire delta, and even has a diagram to the effect, the way the author describes the circuit he is adding the 120 volts from the center tap to either "A" or "C" phase with the 240 volts between "A or C" and "B" phase, which we know is wrong which should be 120*1.732=208

That must be what he is doing, thanks for the response.

 

[LarryFine]

When did we go from 110/220 to 120/240?

You didn't get the memo?

 

[kwired]

Notice how your diagram uses (2) phase conductors plus a neutral. This means the source is a 3-phase open wye.

I know I drew it.

The primary only uses H1, H2, HO on an open delta primary transformer bank even if all three phases are present.

Was answering this question.

Can you elaborate on this? Still has X1, X2, and X3 (A, B, and C), so how is it only 2 phases?

Does not mean it is a two phase system it just uses two phases of the primary source plus the neutral.

Originally Posted by kwired
When did we go from 110/220 to 120/240?

You didn't get the memo?

I don't know where you got the quote from me from I would never have asked such a question.

 

[frenchelectrican]

I just want get a item or two clear up in here and I do not know how the quote got transponed in wrong spot but for the oringal quote and statement between myself and Hurk just go back to the posting # 16 and #17 that where it start.

So I just want to give you a head up before it get misunderstood with quote that all.

Merci,Marc

 

[hurk27]

I just want get a item or two clear up in here and I do not know how the quote got transponed in wrong spot but for the oringal quote and statement between myself and Hurk just go back to the posting # 16 and #17 that where it start.

So I just want to give you a head up before it get misunderstood with quote that all.

Merci,Marc

I saw this last night, All the "Quotes" have the wrong person as listed as the person being quoted????

I think the software for the Bulletin board is kind of messed up:roll:

 

[LarryFine]

I saw this last night, All the "Quotes" have the wrong person as listed as the person being quoted????

I think the software for the Bulletin board is kind of messed up:roll:

I think you're right. Let me try again.

When did we go from 110/220 to 120/240?

You didn't get the memo either?



Added: There we go.

 

[hardworkingstiff]

I don't know where you got the quote from me from I would never have asked such a question.

I'm not sure, but I believe I've just been insulated, but I'm too dumb to know for sure.

 

[LarryFine]

I'm not sure, but I believe I've just been insulated, but I'm too dumb to know for sure.

I can't say for sure whether you've been insulated, but I can confirm you were insulted.



"I'm not sure, but I think we've just been insulted." ~ Capt. Kirk

"I'm sure!" ~ Dr. McCoy - from Mirror, Mirror

 

[Hameedulla-Ekhlas]

I can't say for sure whether you've been insulated, but I can confirm you were insulted.



"I'm not sure, but I think we've just been insulted." ~ Capt. Kirk

"I'm sure!" ~ Dr. McCoy - from Mirror, Mirror

insulation is a new kind of insulted which containes current and voltage both :grin:

 

[jumper]

I can't say for sure whether you've been insulated, but I can confirm you were insulted.



"I'm not sure, but I think we've just been insulted." ~ Capt. Kirk

"I'm sure!" ~ Dr. McCoy - from Mirror, Mirror

insulation is a new kind of insulted which containes current and voltage both :grin:

..............

 

[LarryFine]

insulation is a new kind of insulted which containes current and voltage both :grin:

Electricutting?

Electric slighting?

Conductor berating?

New service degrading?

 

[e57]

insulation is a new kind of insulted which containes current and voltage both :grin:

From someone who spells as if, and may even speak and write english as a 2nd or 3rd language - thats a mighty fine play on words....

 

[hardworkingstiff]

I can't say for sure whether you've been insulated, but I can confirm you were insulted.



"I'm not sure, but I think we've just been insulted." ~ Capt. Kirk

"I'm sure!" ~ Dr. McCoy - from Mirror, Mirror

Can't spell and dumb. I guess I need to move on.