# 3 phase panel grounding



## BWE (Jun 18, 2008)

my friend bought a house and i noticed theirs no main ground wire at the main water pipe and i looked at the 200 amp 3 phase panel and theirs no ground wire. it also has an old diconect switch from the 60s 

i was wondering if its posible it could be grounded another way 
also how do i check if the panel is grounded 

im living in toronto canada
thanks guys


----------



## protechplumbing (Oct 10, 2008)

You have a house that's 3-phase? Is that standard in Canada? Every house I've ever seen in the USA is split-phase.


----------



## Celtic (May 23, 2007)

protechplumbing said:


> You have a house that's 3-phase? Is that standard in Canada? Every house I've ever seen in the USA is split-phase.


There are many homes in the US that are 3Ø ...I wired a few condos that had 3Ø services to them ~ these condos were smaller than my house :whistling

What is "split-phase"?
The majority of US homes have single-phase.


----------



## protechplumbing (Oct 10, 2008)

First and foremost, let me say I'm a plumber not an electrician (though I hope to change that one day).

Split phase IS single phase. Have you ever wondered why there are 2 120v hot that make 240v when both sides are hot? It's because they are 180 degrees out of phase with each other. Single phase actually has 2 phases. It's called "single phase" or more properly "split phase" because only 1 of the 3 phases on the power pole is used and that one phase is split into 2 phases using a neutral center tapped transformer. In short, "single phase" and "split phase" are the same thing.

OK, now all you electricians can flame me to death.........


----------



## protechplumbing (Oct 10, 2008)

Again, pardon the stupid plumber, but how is that done? How do you create a 240V circuit with two 120v phases seperated at 120 degrees?



Celtic said:


> There are many homes in the US that are 3Ø ...I wired a few condos that had 3Ø services to them ~ these condos were smaller than my house :whistling
> 
> What is "split-phase"?
> The majority of US homes have single-phase.


----------



## BWE (Jun 18, 2008)

can anyone answer my question?


----------



## Magnettica (Dec 19, 2006)

protechplumbing said:


> Again, pardon the stupid plumber, but how is that done? How do you create a 240V circuit with two 120v phases seperated at 120 degrees?


Only 3-phase wiring is separated by 120 electrical degrees.

What the OP has is a 3-wire 120/240 "un"solidily grounded single-phase service.


----------



## Speedy Petey (Sep 30, 2003)

BWE said:


> can anyone answer my question?


I can. Ask your boss or J-man.

I don't mean to offend you but you are obviously not experienced enough yet to be working on your own, ESPECIALLY in someone else's house.

The main grounding bonding would take place at the main disconnect.


----------



## protechplumbing (Oct 10, 2008)

Yeah, but I thought he said it WAS 3-phase. So how would you power a 240v appliance such as a dryer or water heater if the legs were spaced by 120Deg. ? That wouldn't make 240v. ???:001_unsure:



Magnettica said:


> Only 3-phase wiring is separated by 120 electrical degrees.
> 
> What the OP has is a 3-wire 120/240 "un"solidily grounded single-phase service.


----------



## protechplumbing (Oct 10, 2008)

I just went back over it. Are you saying that he is mistaken about it being 3-phase. It's actually single phase 3-wire?


----------



## nap (Jan 27, 2008)

protechplumbing said:


> Yeah, but I thought he said it WAS 3-phase. So how would you power a 240v appliance such as a dryer or water heater if the legs were spaced by 120Deg. ? That wouldn't make 240v. ???:001_unsure:


well, if it is a delta supply, then leg to leg would be 240. If it is wye, it would be 208. 

that is how it is.

if it is a wye service, you would have 3 legs of 120 to neutral.

if a center tapped delta, you would have 2 legs of 120 to neutral (actually; grounded conductor) and 1 leg of 208.

these voltages may vary and are dependent on service supply voltages. They should be within +- 10% though.

Oh, and split phase is generally used in reference to a motor type. Single phase would be the proper term for a typical US style residential power supply.


----------



## protechplumbing (Oct 10, 2008)

I see, kinda.


----------



## nap (Jan 27, 2008)

does this help any?

http://www.bmillerengineering.com/elecsys.htm

realize that the single phase in the first pic is the secondary of a transformer that utilizes two of the legs or one tap and the neutral from one of the 3 phase trnasformer configurations for the primary side of that transformer. You can make any voltage you want from any supply voltage you have. It is merely a ratio of primary to secondary windings that determine the secondary voltage compared to the primary voltage.


----------



## Magnettica (Dec 19, 2006)

explaining transformers isn't easy teaching electricians muchless trying to teach a plumber, no offense.


----------



## protechplumbing (Oct 10, 2008)

The single phase stuff makes sense, but I'm lost when I start looking at the 3 phase stuff. Time to pick up the books again.


----------



## Celtic (May 23, 2007)

Let's look at some pictures....


----------



## Magnettica (Dec 19, 2006)

Yes! 

Pictures rule!!


----------



## protechplumbing (Oct 10, 2008)

Excellent pictures. Thank you:clap:

single phase???? I see 2 phases there. see picture.


----------



## protechplumbing (Oct 10, 2008)

Disregard that last post. I get it.


----------



## protechplumbing (Oct 10, 2008)

That secondary winding produces produces 2 phases 180deg apart at points A and C. That was induced from a single phase on the primary winding. That's why it's considered single phase?


----------



## protechplumbing (Oct 10, 2008)

Magnettica said:


> explaining transformers isn't easy teaching electricians muchless trying to teach a plumber, no offense.


 
I do have some electrical background. I took 2 courses of electronics in high school DC then AC. I have an electrician friend that I use to help do side jobs years ago as well. I have been buying all the same books that he has been using in his union study course and reading them here and there. I'm not saying I'm an electrician, but I'm not totally ignorant either.


----------



## Celtic (May 23, 2007)

protechplumbing said:


> That secondary winding produces produces 2 phases 180deg apart at points A and C. That was induced from a single phase on the primary winding. That's why it's considered single phase?


There is actually a thing called 2-phase.
I have never actually seen it used anywhere, but it is addressed in the NEC.


Why it's called 1Ø but utilizes 2 legs....let's just say I used to know, but as time wore on the answer became totally unimportant to me.

If I recall from many years ago...A-C are 120° apart..as are B-C...and B-A


----------



## nap (Jan 27, 2008)

actually those pictures do not show a single phase residential type supply. It is not part of a 3 phase system. it is it's own system.



*SINGLE-PHASE*







*THREE-WIRE*​

*Nominal Voltages**Phase-Phase**Phase-Neutral*240120​This is the most common supply for residences and small commercial facilities. It is also used for the offices in industrial facilities, where it may be derived from a higher available voltage by means of a local transformer



Now, this (above) is the secondary of the transformer. The primary of this transformer would be only A to B, B to C, or C to A on this transformer (below):










So, there is one single winding inducing voltage into another single winding. The voltage transformatoin is determined by the ratio of winding in each of the windings as compared to the other.

then to get the 120 volt on the secondary side, you utilize only 1/2 of the winding on the secondary side, hence the center tap.
and it is called single phase because it has only one phase. it does not utilize 2 phases anywhere. I believe you are confusing the fact you tap onto what would be typically considered 2 phases BUT you are only actually tapping on to both ands of the winding for 1 phase.


----------



## Celtic (May 23, 2007)

http://www.science.smith.edu/~jcardell/Courses/EGR220/ElecPwr_HSW.html


----------



## JohnJ0906 (Jan 7, 2007)

Celtic said:


> Let's look at some pictures....


Celtic and Nap, great pictures and explanations! :thumbsup:

However, I did want to point out that the picture above has a violation _*if *_these are service panels with the 3 main breakers serving as the service disconnects.
The center panel would be in violation of 250.24(C). The neutral has to be run to each service disconnect.


----------



## Celtic (May 23, 2007)

That may very well be true John....I just searched for some transformer pictures and posted a few 

Post #24 has some good information....a good read.


----------



## protechplumbing (Oct 10, 2008)

So to sum it up, it's known as single phase because the "2 phases" are actually induced from a single phase of transmission line. Since 2 phases where "split" from a single phase using a center tapped transformer, single phase is sometimes referred to as "split phase". Am I on the right track here?

Going a step further, points "A" and "C" on the secondary side of the picture posted by celtic is no different than the 3-wire system posted by nap. In naps pic the other 2 windings are not shown because they would be irrelevant in that application?



nap said:


> actually those pictures do not show a single phase residential type supply. It is not part of a 3 phase system. it is it's own system.
> 
> 
> 
> ...


----------



## nap (Jan 27, 2008)

one thing I need to correct; the primary power is actually typically a wye.

here is a schematic for a wye.










the primary side of the transformer would be tapped at either A, B, or C and for one side and the neutral (in the center) for the other. These connections would be connected to what you see here (each end of the 7200 volt winding):










the first transformer is not part of the transformer you have on the pole by your house. It would be the transformer at the substation and would actually have another set of windings for each of the windings you see in the pic for the primary side of that transformer.

the second pic would be what is on the pole at your house. the 7200 volt side is a result of the connections (the A, b, or C and center connection) as described previously. There are not all 3 phases in the transformer on the pole at your house, just one.

sorry for the confusion.

split phase; not a term typically used for a center tapped single phase service. You can call it whatever you want though. It still will hurt you if you touch it improperly.


----------



## protechplumbing (Oct 10, 2008)

Wow, I've learned more from this thread than hours of reading electrical books. Thanks celtic and nap:thumbsup:


----------



## Sparky Joe (Apr 29, 2006)

protechplumbing said:


> Wow, I've learned more from this thread than hours of reading electrical books. Thanks celtic and nap:thumbsup:


Those books you got are great, but like any text book they are basically reference material. You can't learn from them unless someone is teaching you.

Saying "2 phase" out in the field will give the elctricians a good laugh; there's no such thing in a 3 phase system, although it is common to utilize the full 3 phase voltage while using only two of the phases, (i.e. single phase 480, or single phase 208) it is still called single phase. 

To understand phase angles better study up on your trigonometry and adding vectorally. 

A couple new terms for you; 'coil voltage' and 'phase voltage' (and likewise 'coil current' and 'phase current'). I can't define the difference in a simple way mainly because I'm trying to remeber my self, and it doesn't help that the definitions found here ;http://www.mikeholt.com/mojonewsarchive/EC-HTML/HTML/DeltaTransformerCalculations~20030915.htm
Completely contradict what I thought they were, so naturally I site that site as being wrong. 
Look them up in your text book and I think that will clear away some of your fogginess.
These two terms also define the difference between a 'Y' and 'delta' winding configuration and the advantages of one over the other or rather why one is chosen instead of the other depending on whether you need voltage stability or you need current stability.

Keep the good questions coming, and sorry to the OP :thumbsup:


----------

