# How do you tell Delta vs. Wye incoming power



## STS

We are sub metering a building a was asked whether the 600V 400A service was delta or wye and I have no idea... any help is appreciated!


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## HackWork

The best way is to ask a qualified electrician and have him tell you for sure so that there are no mistakes.


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## STS

HackWork said:


> The best way is to ask a qualified electrician and have him tell you for sure so that there are no mistakes.


Is there an easy way to tell? Visually or measuring voltages?


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## HackWork

STS said:


> Is there an easy way to tell? Visually or measuring voltages?


The best way is to ask a qualified electrician and have him tell you for sure so that there are no mistakes.


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## backstay

The left is wye, the right is delta.


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## lighterup

If I were you , In my opinion , the best way is to ask a qualified electrician
and have him tell you for sure so that there are no mistakes.


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## emtnut

STS said:


> Is there an easy way to tell? Visually or measuring voltages?



Yes, Yes, and Yes :thumbsup:


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## STS

These are awesome answers!
I AM an electrician.... this is the first time I have dealt with this and I'm trying to learn on "ELECTRICIAN TALK"!!!!!!!
I know what a diagram of delta vs. wye looks like, I'm looking to find out how to see/test that at the building.
Again any help is appreciated.
Thx!


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## HackWork

STS said:


> These are awesome answers!
> I AM an electrician.... this is the first time I have dealt with this and I'm trying to learn on "ELECTRICIAN TALK"!!!!!!!
> I know what a diagram of delta vs. wye looks like, I'm looking to find out how to see/test that at the building.
> Again any help is appreciated.
> Thx!


The best way is to ask a *qualified* electrician and have him tell you for sure so that there are no mistakes.

A 600V service is nothing to play around with. :whistling2:


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## STS

HackWork said:


> The best way is to ask a *qualified* electrician and have him tell you for sure so that there are no mistakes.
> 
> A 600V service is nothing to play around with. :whistling2:


I am a *qualified *electrician and *master *electrician, not every electrician knows everything about everything and has to ask for help sometimes....I deal w/ 600V everyday, if you're not gonna be any help then don't respond at all...WHO HAS TIME TO POST 18 THOUSAND TIMES!!!! JESUS!


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## wildleg

if you are really an electrician, tell us what the voltages are at the point of service and you might get an appropriate answer.


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## lighterup

If I were you and again just sayin my opinion , you should ask a qualified 
electrician this. A 600V service is nothing to play around with.


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## lighterup

STS said:


> I am a *qualified *electrician and *master *electrician, not every electrician knows everything about everything and has to ask for help sometimes....I deal w/ 600V everyday, if you're not gonna be any help then don't respond at all...WHO HAS TIME TO POST 18 THOUSAND TIMES!!!! JESUS!


*Master*Electrician...well heck , why didn't you say that at the beginning?
You had me going there.


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## STS

wildleg said:


> if you are really an electrician, tell us what the voltages are at the point of service and you might get an appropriate answer.


600v PH TO PH
347V PH TO GROUND


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## lighterup

STS said:


> I am a *qualified *electrician and *master *electrician, not every electrician knows everything about everything and has to ask for help sometimes....I deal w/ 600V everyday, if you're not gonna be any help then don't respond at all...WHO HAS TIME TO POST 18 THOUSAND TIMES!!!! JESUS!


JESUS!? where...you see him , let me know..I want to talk to him.


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## emtnut

STS said:


> 600v PH TO PH
> 347V PH TO GROUND


Why are there 2 different voltages :blink:

Is it 600V or 347V ???


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## RePhase277

STS said:


> 600v PH TO PH
> 347V PH TO GROUND


There's your answer. You can't get 347 volts from a 600 volt delta.


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## emtnut

STS said:


> 600v PH TO PH
> 347V PH TO GROUND


We're a good bunch of guys .... once you get used to us :jester:


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## lighterup

Canada may be different with this issue. As I am not from , nor
worked in Canada , I will just stick to the jokes for now.:jester:


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## STS

RePhase277 said:


> There's your answer. You can't get 347 volts from a 600 volt delta.


Thank you!! That's what we thought just trying to confirm.:notworthy:
So in a 600V delta Ph to ground would remain be 600/600/0?


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## HackWork

lighterup said:


> If I were you and again just sayin my opinion , you should ask a qualified
> electrician this. A 600V service is nothing to play around with.


Not only are you good looking like me, but smart too.


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## 3DDesign

http://www.ecmweb.com/basics/understanding-basics-wye-transformer-calculations


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## frenchelectrican

STS said:


> 600v PH TO PH
> 347V PH TO GROUND


That answer is for the WYE system but if you are dealing with DELTA system that will bite your arse on this one. espcally if you try to read from Line to Ground that will throw ya off on Delta system.

If you did know how to read the voltage with proper test meter you will get the answer way before ya can post it in here. 

Just keep in your mind the 600 volts dont have much margin of error at all.


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## lighterup

emtnut said:


> Why are there 2 different voltages :blink:
> 
> Is it 600V or 347V ???


Maybe OP is using an analog meter..could this be 575 volts ?


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## lighterup

HackWork said:


> Not only are you good looking like me, but smart too.


I'm just screwin around...OP come back man we're just meesin with ya.


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## 3DDesign

https://ctlsys.com/support/electrical_service_types_and_voltages/


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## frenchelectrican

STS said:


> Thank you!! That's what we thought just trying to confirm.:notworthy:
> So in a 600V delta Ph to ground would remain be 600/600/0?


Yes and No depending on the type of grounding on delta system if it was grounded on B phase then ya it correct but floating ( ungrounded ) it can get pretty wonky on reading..


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## telsa

STS said:


> Thank you!! That's what we thought just trying to confirm.:notworthy:
> So in a 600V delta Ph to ground would remain be 600/600/0?


That settles it.

You're not a master electrician.


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## dtmartin408

*Need more information.*

There is not enough information in your question to really help you. Also be careful with some of the responses that people have given. delta systems don't have a neutral. They can also be grounded and ungrounded. They can also be center tapped or corner tapped with respects to the ground. All of these things factor into what type of voltage reading you would have nominally. Even on an ungrounded system you will still read a voltage from phase to ground. Find the transformer and check the name plate on it or if its an pole mount look and see how they are wired up. Be careful and if in doubt seek assistance/information.


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## splatz

dtmartin408 said:


> Also be careful with some of the responses that people have given. delta systems don't have a neutral. They can also be grounded and ungrounded. They can also be center tapped or


You be careful too


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## emtnut

..... :laughing:


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## frenchelectrican

emtnut said:


> ..... :laughing:


Just try that 3Ph 4 W delta like that in our island the only differnce is the voltage .,, our is 240 volts line to netural and 480 volts line to line but wild leg .,, *415*volts line to netual :blink: but yes we do have 240 volts line to neutral and 415 volts line to line wye system.,, 

I get those service call semi often when those bakas try to hook the 240 volts items on 415 volt wild leg connection .,, it is not a neat sight to see when they blow it up.,,


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## scotch

Yes ; the 208 vac neutral to wild leg is in your dreams ! How about 360 vac in fact according to your diagram.


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## Aegis

emtnut said:


> ..... :laughing:




What is that?


Sent from my iPhone using Tapatalk


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## emtnut

scotch said:


> Yes ; the 208 vac neutral to wild leg is in your dreams ! How about 360 vac in fact according to your diagram.


:no: ... Voltage on B phase to neutral is 120 x 1.732


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## emtnut

Aegis said:


> What is that?
> 
> 
> Sent from my iPhone using Tapatalk


Center tapped delta, or high leg delta.


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## splatz

scotch said:


> Yes ; the 208 vac neutral to wild leg is in your dreams ! How about 360 vac in fact according to your diagram.


I remember being confused by this myself. With this drawing, the voltage to the high leg isn't represented by adding the distances on the sides, it's the height of the triangle. The length of a line from the neutral tap on the base of the triangle to the high leg at the top. 

(Since the side is 240, you know it will be less than 240.)


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## telsa

Folks, remember that ex-sex lives in a 230VAC L-N world.

AFAIK, Britain never favored (open) delta Services.

Many European practices are MILES away from NEMA standards... and deliberately so.

They're usually set at 50 Hertz -- with some grids all the way down to 50/3 Hertz. ( Swiss trains started this scheme, IIRC. Mountain yokels were tapping their grid. This extremely low frequency caused even incandescent lamps to flicker madly. This made them irritating to humans ( grow rooms ? ) and obvious to train inspectors. Yes, the trains owned entire hydro-projects.

They're also hugely oriented towards fuses -- circuit breakers were not adopted for years. 

They also, at 230VAC L-N used much smaller conductors... and Ring Circuits are common. Properly designed, a ring circuit permits even more savings on copper. The only nations with decent copper deposits, in Europe, were Sweden and Poland. This fact entirely explains why the Swedes were such a Big Factor in 19th Century electrical progress. 

( Britain was a major copper miner -- in the Bronze Age, BTW. By the 19th Century it was cheaper for Britain to trade for copper: USA, Canada, Australia... et. al. The real fans of copper economy were France and Germany. )

All of the above, and much more, makes it deuce difficult for Europeans to chat with Americans and Canadians on matters electrical.

It's why ex-sex is such a total waste of attention. Everything he sees posted here, stumps him.

&&&&

Which brings us to the craziness of Afghanistan and Iraq. These are cross breed electrical grids.

You don't DARE touch anything without being cross trained in BOTH NEMA and EIC standards.

The scariest stuff: half-breed EIC-NEMA systems... with wire color combos that would throw off anyone not a Master Electrician.


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## emtnut

Like this ...


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## scotch

I stand corrected....the Pythagorean formula stuff was hiding in the deep recesses of my brain ! I should have remembered since I spent lots of time at a Telco office when Poco hooked up new transformer wrong and ....Bang !....there went all the fluorescent lighting !


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## Eg519

Since this is linework show us a picture of the transformer (bank?) . If it is a bank look for two primary insulated bushings on each transformer. If it's a three phase transformer it's hard to tell. Check the name plate either way. Post a pic


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## Cl906um

telsa said:


> Folks, remember that ex-sex lives in a 230VAC L-N world.
> 
> AFAIK, Britain never favored (open) delta Services.
> 
> Many European practices are MILES away from NEMA standards... and deliberately so.
> 
> They're usually set at 50 Hertz -- with some grids all the way down to 50/3 Hertz. ( Swiss trains started this scheme, IIRC. Mountain yokels were tapping their grid. This extremely low frequency caused even incandescent lamps to flicker madly. This made them irritating to humans ( grow rooms ? ) and obvious to train inspectors. Yes, the trains owned entire hydro-projects.
> 
> They're also hugely oriented towards fuses -- circuit breakers were not adopted for years.
> 
> They also, at 230VAC L-N used much smaller conductors... and Ring Circuits are common. Properly designed, a ring circuit permits even more savings on copper. The only nations with decent copper deposits, in Europe, were Sweden and Poland. This fact entirely explains why the Swedes were such a Big Factor in 19th Century electrical progress.
> 
> ( Britain was a major copper miner -- in the Bronze Age, BTW. By the 19th Century it was cheaper for Britain to trade for copper: USA, Canada, Australia... et. al. The real fans of copper economy were France and Germany. )
> 
> All of the above, and much more, makes it deuce difficult for Europeans to chat with Americans and Canadians on matters electrical.
> 
> It's why ex-sex is such a total waste of attention. Everything he sees posted here, stumps him.
> 
> &&&&
> 
> Which brings us to the craziness of Afghanistan and Iraq. These are cross breed electrical grids.
> 
> You don't DARE touch anything without being cross trained in BOTH NEMA and EIC standards.
> 
> The scariest stuff: half-breed EIC-NEMA systems... with wire color combos that would throw off anyone not a Master Electrician.


Not to sound absent minded, but what the heck is a ring circuit? Three hots and a neutral?


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## B-Nabs

Cl906um said:


> Not to sound absent minded, but what the heck is a ring circuit? Three hots and a neutral?


This thingy









Sent from my SM-G920W8 using Tapatalk


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## Bird dog

B-Nabs said:


> This thingy
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Sent from my SM-G920W8 using Tapatalk


And usually protected by a RCD or a bkr with integral RCD (RCBO?) (Residual Current Device similar to our GFI).

https://en.wikipedia.org/wiki/Residual-current_device


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## hardworkingstiff

Cl906um said:


> Not to sound absent minded, but what the heck is a ring circuit? Three hots and a neutral?


The professor doesn't like wikipedia, but this does an OK job of explaining it. 
https://en.wikipedia.org/wiki/Ring_circuit


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## Cl906um

hardworkingstiff said:


> The professor doesn't like wikipedia, but this does an OK job of explaining it.
> https://en.wikipedia.org/wiki/Ring_circuit


Looks like a bad idea. When does current ever take the long way? This coworker of mine did some work at an engineers house. He had brought a return back to the panel and landed it back on the breaker and another on the neutral. He told him that it couldn't be done because it was a parallel #12. So he has a bunch of wire nuts for the twice as many cables in the box. His reason was efficiency and depending on which side the load was on in the circuit, the current would take the shortest route. My coworker didn't let it fly since we were going to get our work inspected.


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## hardworkingstiff

Cl906um said:


> Looks like a bad idea. When does current ever take the long way? This coworker of mine did some work at an engineers house. He had brought a return back to the panel and landed it back on the breaker and another on the neutral. He told him that it couldn't be done because it was a parallel #12. So he has a bunch of wire nuts for the twice as many cables in the box. His reason was efficiency and depending on which side the load was on in the circuit, the current would take the shortest route. My coworker didn't let it fly since we were going to get our work inspected.


You are correct that it is not allowed by the NEC. As far as good/bad idea, IDK. As far as current taking the shortest path, ..... current takes all paths, more of it would flow on the shortest path because it's lower resistance, but it will take all paths.


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## Bird dog

Cl906um said:


> Looks like a bad idea. When does current ever take the long way? This coworker of mine did some work at an engineers house. He had brought a return back to the panel and landed it back on the breaker and another on the neutral. He told him that it couldn't be done because it was a parallel #12. So he has a bunch of wire nuts for the twice as many cables in the box. His reason was efficiency and depending on which side the load was on in the circuit, the current would take the shortest route. My coworker didn't let it fly since we were going to get our work inspected.


Sounds like an engineer that's not smart.


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## frenchelectrican

hardworkingstiff said:


> The professor doesn't like wikipedia, but this does an OK job of explaining it.
> https://en.wikipedia.org/wiki/Ring_circuit


I used to live in France before so I am famuair with the dammed ring circuits they are some way not bad but majorty of time it is a pain in arse for troubleshooting the circuits.,

I know I did talk to couple legit UK electricians and they are saying the same thing as I will speak is they are start to drop the ring circuit out of the picture soon due hard to fix it correct and what more not too far the UK will have differnt type of Arc fault protection comming up soon., not sure what it will be covered yet. 

And ya I done ran into few ring circuits before.,, few in France and I know at least once in Wisconsin that I do know.,, but over here in Philippines it is not allowed to run ring circuits at all.


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