# using high leg 208



## Wiresmith (Feb 9, 2013)

does anyone know of problems using 207v from a 4 wire delta, any power quality problems or anything else? thanks


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## RePhase277 (Feb 5, 2008)

The main problem is that no single pole breaker is rated for it unless you use a 277 volt breaker.


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## Southeast Power (Jan 18, 2009)

hd13 said:


> does anyone know of problems using 208 from a 4 wire delta, any power quality problems or anything else? thanks


We have thousands of those services here and I think, after 35 plus years, I have only found one hacktard install that tried it.
We just don't.


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## telsa (May 22, 2015)

The stinger is only to be loaded as leg of 3-phase balanced loads.

Period.

Most are generated by way of an open-delta scheme.

Never forget that.


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## Forge Boyz (Nov 7, 2014)

telsa said:


> The stinger is only to be loaded as leg of 3-phase balanced loads.
> 
> Period.
> 
> ...


That depends on your transformers. I do some work in a welding shop that has 2 padmount 50kva's in an open delta setup. When they expanded i used all three phases for single phase welder receptacles to balance out their load, which is mostly welders.

Sent from my XT1585 using Tapatalk


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## samgregger (Jan 23, 2013)

What are you planning to use it for?


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## matt1124 (Aug 23, 2011)

I knew a guy that used to put lighting on the high leg of 120/240 open delta. Electronic T8 ballasts want 90-277v, fell right in that. Worked fine, wouldn't want to do it as normal practice though.


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## Southeast Power (Jan 18, 2009)

Forge Boyz said:


> That depends on your transformers. I do some work in a welding shop that has 2 padmount 50kva's in an open delta setup. When they expanded i used all three phases for single phase welder receptacles to balance out their load, which is mostly welders.
> 
> Sent from my XT1585 using Tapatalk


This is the intended purpose of that service.
All loads on the hi leg are phase to phase.


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## Forge Boyz (Nov 7, 2014)

Suncoast Power said:


> This is the intended purpose of that service.
> All loads on the hi leg are phase to phase.


That was my point. Telsa was saying it was only for 3 phase loads. I can understand doing that if the second transformer was a lot smaller that the main one. 

Sent from my XT1585 using Tapatalk


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## RePhase277 (Feb 5, 2008)

matt1124 said:


> I knew a guy that used to put lighting on the high leg of 120/240 open delta. Electronic T8 ballasts want 90-277v, fell right in that. Worked fine, wouldn't want to do it as normal practice though.


I wouldn't really have a problem doing it if two conditions were met:

1) The single pole circuit breaker used had a straight voltage rating that allowed it, and
2) The transformer with the neutral tap was sized appropriately for the additional load.


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## sbrn33 (Mar 15, 2007)

Suncoast Power said:


> We have thousands of those services here and I think, after 35 plus years, I have only found one hacktard install that tried it.
> We just don't.


I don't think I have ever had an apprentice that did not do this at least once. Most of the times it was caught in time. The good thing is it is a mistake you only make once.


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## Big John (May 23, 2010)

Three potential problems when single-phasing a high leg:

1) Breakers must not be slash rated, they have to be rated for full 208V.

2) High leg transformer is often smaller, especially on an open delta, so you gotta be careful you don't overload.

3) Any current you draw off the high leg also has to flow through the windings on you 120/240 tranny, so watch overload there, too.

I've never built a high leg, but the method I've seen that I really like is set a single phase panel with only A and C feeding it, and then a small three phase panel with no neutral.

Keeps you from having all those empty spaces and reduces screwups.


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## ElectricalArtist (Jul 2, 2014)

Not identified and not on the correct phase is the usual problems. I've seen guys hook up a 120 load on the 208 phase.


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## ElectricalArtist (Jul 2, 2014)

Big John said:


> Three potential problems when single-phasing a high leg:
> 
> 1) Breakers must not be slash rated, they have to be rated for full 208V.
> 
> ...


That's a pretty good one, might do that when I run into a high leg


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## samgregger (Jan 23, 2013)

ElectricalArtist said:


> Not identified and not on the correct phase is the usual problems. I've seen guys hook up a 120 load on the 208 phase.


We had someone do that for some TV receptacles put in after the fact for a sandwich shop. The TVs, with their fancy switching power supplies, didn't care but the cable guy fried a few boxes before we figured out what was wrong.


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## sbrn33 (Mar 15, 2007)

We have quite a few delta systems around here. I think it is because my POCO likes it and they can get by with 2 transformers. If I do one from new I do like you said and put in a single phase sub. 
Most of the time they just put in two separate services. 1 three phase and 1 single phase.


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## JRaef (Mar 23, 2009)

Again, use it for WHAT? 

What load do you have that requires *208V Line the NEUTRAL*? 

Because that's *the ONLY way you get 208V on that leg*. 
Line to Line it is 240V, 2 lines or 3 lines, doesn't matter, 240V. 
A to N = 120V, 
C to N = 120V, 
B to N = 208V. 
A to B, B to C or C to A = 240V

So if you have a load that can ONLY use 208V, it likely is _expecting_ 208V Line to Line, not Line to Neutral. Would it work? Probably, but IF, inside of that device, they are expecting a _*maximum line to ground reference potential of 120V*_, which is what you WOULD expect on a 208 or 240V rated device, then you are EXCEEDING that by giving it 208V Line to Neutral.

Why flirt with disaster here?


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## LGLS (Nov 10, 2007)

JRaef said:


> Again, use it for WHAT?
> 
> What load do you have that requires *208V Line the NEUTRAL*?
> 
> ...


That's my question, use it for what? WTF runs on 208v??? Who would manufacture something requiring 208v and why?


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## Big John (May 23, 2010)

LawnGuyLandSparky said:


> That's my question, use it for what? WTF runs on 208v??? Who would manufacture something requiring 208v and why?


I've been tempted to put multivoltage ballasts on them before.


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## RePhase277 (Feb 5, 2008)

LawnGuyLandSparky said:


> That's my question, use it for what? WTF runs on 208v??? Who would manufacture something requiring 208v and why?


Any single phase 208 volt equipment. Ballasts, pumps, fans, tools, etc. There's tons of 208 volt stuff. Granted, it is usually on double pole breakers, but it would happily work on 208 volts line-to-neutral.


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## telsa (May 22, 2015)

RePhase277 said:


> Any single phase 208 volt equipment. Ballasts, pumps, fans, tools, etc. There's tons of 208 volt stuff. Granted, it is usually on double pole breakers, but it would happily work on 208 volts line-to-neutral.


True, but why not feed them 240 VAC ?


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## RePhase277 (Feb 5, 2008)

telsa said:


> True, but why not feed them 240 VAC ?


That's what should be done. But we're talking hypothetical here. Hypothetically, there's a bunch of single spaces available on the B phase. If you had a single pole breaker rated for it, said breaker would be cheaper than the cost of a double pole. It would be ideal for lighting too. You would get the benefit of higher voltage/reduced amps/smaller wire, while also using single pole breakers and switches, similar to 277.

I can see the uses, but the hoops you have to jump through to make it feasible are more costly.


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## JRaef (Mar 23, 2009)

RePhase277 said:


> Any single phase 208 volt equipment. Ballasts, pumps, fans, tools, etc. There's tons of 208 volt stuff. Granted, it is usually on double pole breakers, but it would happily work on 208 volts line-to-neutral.


But again only as long as you ABSOLUTELY KNOW that nothing inside of it is designed around an expected ground reference voltage of 120V. That is likely the case on a lot of electronics. Sure, some things designed as "universal input voltage" are going to be fine, but how is the average Joe going to know for ABSOLUTE sure? If you are wrong, and fry something, what you thought you saved on a 1 breaker pole is long gone. 

And, as pointed out by others, you cannot use a "Slash Rated" breaker, for exactly the same reason. So if you look, most 1 pole plug in breakers are only rated for 120V. You can't use those for this. So now you have to go with a straight 250V rated 1 pole breaker and it's going to be different than the rest, may not fit the trim, etc etc etc. not worth the trouble.


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## telsa (May 22, 2015)

JRaef said:


> But again only as long as you ABSOLUTELY KNOW that nothing inside of it is designed around an expected ground reference voltage of 120V. That is likely the case on a lot of electronics. Sure, some things designed as "universal input voltage" are going to be fine, but how is the average Joe going to know for ABSOLUTE sure? If you are wrong, and fry something, what you thought you saved on a 1 breaker pole is long gone.
> 
> And, as pointed out by others, you cannot use a "Slash Rated" breaker, for exactly the same reason. So if you look, most 1 pole plug in breakers are only rated for 120V. You can't use those for this. *So now you have to go with a straight 250V rated 1 pole breaker and it's going to be different than the rest, may not fit the trim, etc etc etc. not worth the trouble.*


You could remediate this defect by putting a fuse in series with the 120 VAC C/B. What a hassle.

Then there's the reality that the next guy to come along is NOT going to appreciate that that bus rail is really at 208 VAC L-N at first glance. 

Indeed, there are a TON of residential electricians who'll dive right in -- not knowing the first thing about such Services.

Messing with the stinger is a road to ruin.

I really like the double panel solution. 

My Poco hates center-tapped delta Services. So they exist now as legacies. Fat chance PG&E will install a new one. It has to be 208Y120 these days. ( or 480Y277) That's all that the Poco wants to touch.


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## JRaef (Mar 23, 2009)

PG&E will do it by request, but they will ask for a justification as to why you won't take 208Y120, then a lot of people fail at that. They make the claim that they have 230V motors and will void the warranty by giving them 208V but then when PG&E asks for the documentation, the user discovers it isn't true if the equipment is new enough to have a warranty. The exception I've seen is small submersible sewage lift pumps, usually built with IEC motor specs that are 230V 50/60Hz, so they have zero tolerance to accept 208V. But submersible wells here in CA (as you've likely seen) are all getting so deep that they have gone to 480V anyway.


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## sbrn33 (Mar 15, 2007)

What about 2 pole breaker, like for a welder. Does that have to be non slash rated also?


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## RePhase277 (Feb 5, 2008)

sbrn33 said:


> What about 2 pole breaker, like for a welder. Does that have to be non slash rated also?


Yes, but non-slash rated double poles actually exist.


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## RePhase277 (Feb 5, 2008)

It's a shame that utilities can't see or have forgotten the benefits of delta services. A delta connected system is a dead short to odd harmonics. Deltas produce very clean power for sensitive equipment. Motors tend to like them better than wye. And since current divides among the delta windings, there is less stress on each transformer than in a similarly sized wye.


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## telsa (May 22, 2015)

JRaef said:


> PG&E will do it by request, but they will ask for a justification as to why you won't take 208Y120, then a lot of people fail at that. They make the claim that they have 230V motors and will void the warranty by giving them 208V but then when PG&E asks for the documentation, the user discovers it isn't true if the equipment is new enough to have a warranty. *The exception I've seen is small submersible sewage lift pumps, usually built with IEC motor specs that are 230V 50/60Hz, so they have zero tolerance to accept 208V.* *But submersible wells here in CA (as you've likely seen) are all getting so deep that they have gone to 480V anyway.*


This is where autoformers come in.

I was shocked to discover that PG&E tariffs are such that MOST farmers are using Diesels to power their water lift. 

The Poco has to size their entire system on the assumption that every farmer is going to -- pretty much -- fire off their pumps at the same time. ( Such a seasonal demand. ) The rest of the year, farmers don't want or need any significant water at all. 

But, the Poco HAS to keep dinging them for the infrastructure.

Farmers don't pay road tax when they buy Diesel fuel.

The result is we have a blended system... with it weighted towards Diesel... MUCH to my surprise.

This has become a political issue -- as Jerry Brown wants farmers to stop using Diesel... just to save the climate. 

The farmers counter with: "We can't possibly afford the 'demand charges' from the Poco."

The Poco replies: "That wire and plant didn't fly out of my armpit. It costs a fortune. Much more than wiring through San Francisco. There's no load density."

( This reality is why FDR established the Rural Electrification Act. )


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## sbrn33 (Mar 15, 2007)

RePhase277 said:


> Yes, but non-slash rated double poles actually exist.


Between this and the nema 12 enclosures I am doomed.


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## micromind (Aug 11, 2007)

There area a number of 240∆ systems around here, mostly in older parts of town. Some subdivisions built in the 70s have them too, those are a single phase panel with a ∆ breaker for the A/C. 

When I build or modify one that's in a building, I will usually set 2 panels, a single phase one and a 3Ø next to it, and chase the panels together. Both have neutrals. 

I also use the high leg and one of the other phases for 240 loads that do not involve the neutral.

I haven't used the high leg to neutral......yet........lol. But only because of breaker ratings. 

If I remember, Square D has an alternate rating of 240/415 on their QO and QOB breakers. It's been a long time since I've seen it and I don't know if it applies to all breakers or only special ones. I also remember the AIC was 5,000 amps. 

When connecting a VFD to a ∆ system, usually the MOVs need to taken out of the circuit. Sometimes this involves cutting jumpers, sometimes just moving them. 

Another issue is with available fault current. A closed ∆ can have pretty high fault current because all 3 transformers will contribute to the fault. An open ∆ is less. 

I actually like the system, if nothing else, it makes me think once in a while......lol.


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## Wiresmith (Feb 9, 2013)

samgregger said:


> What are you planning to use it for?


not planning on doing it just thinking. we have a lot of these services in my area, i have seen the 208 single phase used for equipment rated for it and hadn't noticed any problems but didn't log any measurements. i was wondering if anyone may have done any measurement logging on these systems and what kind if any power quality problems occur, being you are using all three xfmrs on a single phase load. and any other problems

thanks for everyone's input


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## Wiresmith (Feb 9, 2013)

JRaef said:


> Again, use it for WHAT?
> 
> What load do you have that requires *208V Line the NEUTRAL*?
> 
> ...


have you worked on corner grounded systems, we have a lot of those as well. 480v to ground or 240v to ground


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## RePhase277 (Feb 5, 2008)

hd13 said:


> have your worked on corner grounded systems, we have a lot of those as well. 480v to ground or 240v to ground


I personally have seen enough corner grounded systems to know one when I see one.


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## Angelic (Dec 2, 2018)

*Old thread new question that fits*

Wouldn't it be very risky to use high leg to ground to achieve 208 if needed, going to equipment that containing circuitry or control boards? Even if you had an oven that required 208, if it also had other components such as lights they would blow? Am I right?


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## micromind (Aug 11, 2007)

Angelic said:


> Wouldn't it be very risky to use high leg to ground to achieve 208 if needed, going to equipment that containing circuitry or control boards? Even if you had an oven that required 208, if it also had other components such as lights they would blow? Am I right?


If the load involves the neutral, it is unwise to use the high leg though it usually can be done. The reason being that the next guy who works on it will almost certainly not realize that one of the hots is actually 208 to neutral. 

If you're using the high leg to neutral to get 208 and it feeds an oven with 120 lights, yes indeed, it'll blow the lights because there is no 120 present. 

Circuit boards are questionable. The power components of the board can usually handle 208 to ground but the surge suppression might be designed around 120 to ground. 

If the equipment is designed for operation outside of the US, the system is likely 240 to ground so using the high leg to neutral would be ok except for maybe 208 vs. 240. 

I know for a fact that a 4' 2 lamp T12 240 volt ballast (yes, they made them years ago.....) will last more than 15 years being powered by the high leg to neutral and its replacement, a 2 lamp T8 120 - 277 electronic ballast has lasted more than 5 years. Continuous operation. 

I stated more than 15 years because it was an existing installation when I started working on the building. It could have been this way for a very long time, the building and the fixture are pretty old.


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## Unionpride277 (Oct 31, 2018)

Wiresmith said:


> JRaef said:
> 
> 
> > Again, use it for WHAT?
> ...


When I first was in a building with this system I could not understand it at all .

It actually still dosnt make sense to me . 

I’ve only seen it once in a very old factory . 

I forgot the voltages I think it’s 

A- ground 240v
B-ground 0v
C- ground 240v

And any phase to phase combination is 240v 

What is the purpose for grounding the b phase if most of the loads will be 3 phase loads ?

And am I correct with the voltages ?


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## telsa (May 22, 2015)

Unionpride277 said:


> When I first was in a building with this system I could not understand it at all .
> 
> It actually still dosnt make sense to me .
> 
> ...


You can get away with using a 1-phase, two-leg, panel for a 3-phase system.

One has to keep in mind that the Grounded Conductor is carrying FULL ampacity... right along with the Hot Phases. Further, the Hot Legs will be a full 240VAC above ground. This means that your circuit breaker selection is restricted to those so rated.

The scheme made even more sense during the age of fuses.

It's not popular with Pocos.

My Poco only wants to see:

1-phase 120/240 for small loads

3-phase 208Y120

3-phase 480Y277

Anything else it's a fight.

This simplification drastically increases Poco crew safety. 

They've even broken the loads down into separate crews, Residential and 3-phase.

The old 'clever' solutions bit back... HARD.

For your edification: EUSERC. Bing it. :smile:


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## Unionpride277 (Oct 31, 2018)

telsa said:


> Unionpride277 said:
> 
> 
> > When I first was in a building with this system I could not understand it at all .
> ...


Ive only really seen
120/240 single phase
120/208 3 phase
277/480 3 phase 

Could you explain the concept of using a single phase two leg system for , 3 phase 

If you have a single phase panel 
A,b,a,b

How would you be able to pull 3 phase loads off of it


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## Angelic (Dec 2, 2018)

*Not looking to use 3 phase*

I am only looking to test wire a piece of lab equipment that is tagged with a requirement of 208v single phase. And I only have 3 Phase outlet to pull from. 120-120-208.


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## telsa (May 22, 2015)

Unionpride277 said:


> Ive only really seen
> 120/240 single phase *[ Here the neutral is a GROUNDED CONDUCTOR.]*
> 120/208 3 phase
> 277/480 3 phase
> ...


These days such a set-up would be deemed WEIRD.


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## telsa (May 22, 2015)

BTW, the 1-phase panels that can accept suitably rated circuit breakers won't come cheap.

Think Bolt-On type C/Bs.


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## splatz (May 23, 2015)

@Unionpride277 - The high leg makes perfect sense if you study the picture. 










It's like you start with a delta, and center tap one leg for 120V loads. 

Or, you start with regular residential service, and add a wire to a third transformer terminal, so you have three phase available too. 

The only thing that's hard to understand is that that high leg to neutral is 208V but there you just have to do the math, the vector addition, or realsitically know what to multiply by 1.73. 

It's 

L1-L2 = L2-L3 = L3-L1 = 240V
L1-N = L2-N = 120V
L3-N = (120) * 1.73 = 208V
N-G 0V

It makes a lot of sense for say a auto repair shop, or a small machine shop or a cabinet shop. You can wire the office, bathrooms, lights, etc. with regular split phase 240/120 like a house, and you can wire the machinery with 240V three phase. 

The problem is someone that's not paying attention will wire a 120V load with L3-N and get stung by the unexpected 208V. That's why they call it the stinger. You could also call it the dumbass. 

The setup where you set up a split phase panel on L1-L2-N and a three phase panel with L1-L2-L3 would make it more goof proof. 



Unionpride277 said:


> When I first was in a building with this system I could not understand it at all .
> 
> It actually still dosnt make sense to me .
> 
> ...


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## Southeast Power (Jan 18, 2009)

Angelic said:


> I am only looking to test wire a piece of lab equipment that is tagged with a requirement of 208v single phase. And I only have 3 Phase outlet to pull from. 120-120-208.


If this is a test or an experiment, you can give yourself permission to do what ever you like. 
If you are setting this up for someone else to use and then walking away, it becomes a problem.


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## Southeast Power (Jan 18, 2009)

Unionpride277 said:


> When I first was in a building with this system I could not understand it at all .
> 
> It actually still dosnt make sense to me .
> 
> ...


You realize that you described a "corner grounded" delta and not an open delta right?


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## mbednarik (Oct 10, 2011)

micromind said:


> If the load involves the neutral, it is unwise to use the high leg though it usually can be done. The reason being that the next guy who works on it will almost certainly not realize that one of the hots is actually 208 to neutral.
> 
> If you're using the high leg to neutral to get 208 and it feeds an oven with 120 lights, yes indeed, it'll blow the lights because there is no 120 present.
> 
> ...


That's why the high leg has to be orange in color.


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## micromind (Aug 11, 2007)

Unionpride277 said:


> Ive only really seen
> 120/240 single phase
> 120/208 3 phase
> 277/480 3 phase
> ...


A greened B system is very similar to a 120/240 single phase system except there is no 120. You'll have 240 from either phase to the 'neutral' and 240 from either phase to the other one. 

With this system, you need a 2 pole breaker to supply a 3Ø load. The top pole is phase A, the 'neutral' is phase B and the bottom pole is phase C. 

A 3Ø load cares about phase to phase voltage, it doesn't care about phase to ground. 

You can supply 240 single phase loads with a single pole breaker and the 'neutral' or use a 2 pole breaker. 

You'll need breakers rated at 240, not 120/240. The 2 pole ones are available but a bit more $$$ than a normal one. Not sure about the single pole ones.


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## Unionpride277 (Oct 31, 2018)

Southeast Power said:


> Unionpride277 said:
> 
> 
> > When I first was in a building with this system I could not understand it at all .
> ...


Yes corner grounded delta .

Open grounded delta is the system with the high leg ?


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## frenchelectrican (Mar 15, 2007)

Unionpride277 said:


> Ive only really seen
> 120/240 single phase
> 120/208 3 phase
> 277/480 3 phase
> ...


If you come to my location you will be suprised how many voltage we can get in our Philippines system.,

Single phase 240 volt line to netural
Single phase 400 volt line to line ( yes we do get single phase 480 line to line too) 
Three phase 240 volt detla or wye 
Three phase 415Y240 volt Wye
Three phase 480Y277 Wye

The only quirk is the standariszed voltage between any islands the voltage will varies some. 

And yes what I posted above we do run on 60 HZ system too. 
Three phase 400 volt delta or wye 
Three Phase 480 delta or wye.


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## Southeast Power (Jan 18, 2009)

Unionpride277 said:


> Yes corner grounded delta .
> 
> Open grounded delta is the system with the high leg ?


Yes. 

A delta can be open or closed.
The POCO likes open here as they can build them with two phases and two transformers.


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## varmit (Apr 19, 2009)

The purpose of corner grounding a phase is to create a fault return path to allow the over current device to trip. On am ungrounded delta system, common on older installations, there is no fault return path, so if there is an accidental high resistance ground fault of one phase, the wiring can set there and fry until it shorts to another phase. I have seen this many times.

By bonding one phase to the GEC, you establish a fault return path if there is a ground fault on another phase. The limitation of a corner grounded system are the possibility of high fault current on a phase to phase short. Corner grounding is usually used on less than 400 amp systems. Larger ampacity systems normally use resistance grounding to limit fault current.

Delta ungrounded systems are supposed to have indication of a ground fault if there is a fault in any one phase. The ground fault can be located when there is an opportunity- hopefully before there is a fault on a second phase. The original purpose of this system was to allow an industrial process to continue uninterrupted until the process could be shut down safely for maintenance. 

IF YOU ARE UNSURE OF WHAT POWER SYSTEM THAT YOU ARE DEALING WITH - CHECK AND VERIFY.


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## Angelic (Dec 2, 2018)

*Restate Earlier Post*

Sorry for the confusing earlier post. I only intended to list available voltage. Not necessarily in that order. The piece of equipment that I am testing for my self is a refrigerated centrifuge used in labs. Tag shows 208v/30amp/single phase/4350 watt. Currently I have it connected to the two 120 lines for a 240 connection. Compressor is drawing around 33 amps, but seems to be functioning correctly, just high amp draw. Capacitor has been changed out because the capacitance was a little low. I am looking now at doing freon charge test, but it is difficult to keep it running long enough to get good reading. Someone suggested to me that I might want to connect it to the high leg and ground to get closer to the 208v. I am afraid this could cause other issues. The unit contains many control boards and several transformers with unknown ratings.


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## sbrn33 (Mar 15, 2007)

Wiresmith said:


> does anyone know of problems using 207v from a 4 wire delta, any power quality problems or anything else? thanks


Favorite question of the year.


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## micromind (Aug 11, 2007)

Angelic said:


> Sorry for the confusing earlier post. I only intended to list available voltage. Not necessarily in that order. The piece of equipment that I am testing for my self is a refrigerated centrifuge used in labs. Tag shows 208v/30amp/single phase/4350 watt. Currently I have it connected to the two 120 lines for a 240 connection. Compressor is drawing around 33 amps, but seems to be functioning correctly, just high amp draw. Capacitor has been changed out because the capacitance was a little low. I am looking now at doing freon charge test, but it is difficult to keep it running long enough to get good reading. Someone suggested to me that I might want to connect it to the high leg and ground to get closer to the 208v. I am afraid this could cause other issues. The unit contains many control boards and several transformers with unknown ratings.


A motor that's designed for 208 and run on 240 will draw excessive current because the core is saturated. 

In your case, look at what the control boards are powered by. If they are powered by a transformer, it won't matter what the voltage is to ground. The compressor won't care either. 

Another way to do this is to use a buck-boost transformer to buck some of the 240 off. A 24 volt model will do though 32 volts will be better.


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## telsa (May 22, 2015)

So this was really a DIY post.

Great.


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## Angelic (Dec 2, 2018)

*Yes Diy*

Yes this is a diy post. My primary knowledge is in the electronics field. This is the first time that I have worked with a piece of equipment calling for 208v. I thank everyone for their input. Everyday I learn something new, if not it would be a day wasted.


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## brian john (Mar 11, 2007)

With a separately derived system

Single phase X1, X2
3-phase wye X1, X2, X3, X0
Delta X1, X2, X3
Center tapped Delta X1, X2, X3, N-XO

Earth (dirt or building steel to include any electrode) Could care less if you ground the system or ground any of the X's above, the only thing that changes are your voltage relation of the ungrounded ground to ground.


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## Wiresmith (Feb 9, 2013)

sbrn33 said:


> Favorite question of the year.


why's that?

i have to read back through the thread, i don't remember the conclusion i came to from the responses. lol


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## frenchelectrican (Mar 15, 2007)

Angelic said:


> Yes this is a diy post. My primary knowledge is in the electronics field. This is the first time that I have worked with a piece of equipment calling for 208v. I thank everyone for their input. Everyday I learn something new, if not it would be a day wasted.


This part is not a DIY at all due it been discussed few time before with wild leg system ( centre tapped delta system )

and please fill your profile if you are a legit electrician.


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## MDShunk (Jan 7, 2007)

ElectricalArtist said:


> Not identified and not on the correct phase is the usual problems. I've seen guys hook up a 120 load on the 208 phase.


That's a big thing to look out for when connecting 240V single phase 3-wire circuits, like electric clothes dryers. The element is 240, but the timer is 120V L-N. If it's the wrong L-N, you just bought someone's clothes dryer.


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## MTW (Aug 28, 2013)

The low spark of high legged boys...wasn't that a Cream song?


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## brian john (Mar 11, 2007)

MTW said:


> The low spark of high legged boys...wasn't that a Cream song?


NOPE - Traffic


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## Angelic (Dec 2, 2018)

*Two Phase or Single Phase*

allaboutcircuits.com/threads/is-the-american-120-240-volt-system-single-phase-or-two-phase.105861/page-2


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## Angelic (Dec 2, 2018)

*Electronics to Electrician*



frenchelectrican said:


> This part is not a DIY at all due it been discussed few time before with wild leg system ( centre tapped delta system )
> 
> and please fill your profile if you are a legit electrician.



As I have stated electronics tech. There is much cross over.


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## John Valdes (May 17, 2007)

Angelic said:


> As I have stated electronics tech. There is much cross over.


Please fill out your profile. Thanks.


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