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-   -   What type of electric do I have in mu house? (http://www.diychatroom.com/f18/what-type-electric-do-i-have-mu-house-11320/)

SleepnZJ 09-06-2007 05:05 PM

What type of electric do I have in mu house?
 
I'm turning my basement in to my work shop, I have a bunch of single phase 120/240 volt equipment and I just picked up a lathe that is 3 phase 220. I figured that I will use a phase converter for all the 3 phase equipment (1 for now and one more piece down the road for a total of 2). My question is I think that I might already have 3 phase in the house.

If you open up the cabinet below the meter you see where the wires come into the house (total of 4) then they go up through the meter then through a conduit to the main breaker panel and one small breaker box for the AC.

Now I put a volt meter on the wires in the cabinet where the wires come into the hose. The wires go as follows "Red, Black, Black" and a white wire at the bottom of the cabinet which I assume is the ground. When it test across the red and white I get 210 volts, when I test the other two black wires across the white I get 120 volts. When I test across both the blacks I get 240 volts and when I test across either of the blacks to the red I get 240 volts.

The words "caution red leg first phase on block" and a 3,2,1, underneath the wires in the cabinet.

So what do you guys think, do I have 1 phase or 3 phase coming into the house.

P.S. Here's a link to a pic of the cabinet.

http://good-times.webshots.com/photo...30078541pNfGlh

Speedy Petey 09-06-2007 05:37 PM

Well damn if that doesn't look like 3-phase!

Where is this house?

sluggermike 09-06-2007 06:34 PM

I thought that three phase was for industrial use only. It's my understanding that it is more efficient and used for heavy industrial equipement. I'm wondering why it would be in a residence?

SleepnZJ 09-06-2007 07:40 PM

The house is in Souther NY, right out side New York City. The thing is I though 3 phase had equal voltage across all three legs. When I put the meter on it I get 210 120 120.

Speedy Petey 09-06-2007 08:10 PM

You have a 120/240v delta 3 phase system with a high leg of ~208v.
That must be an old industrial building.

Stubbie 09-07-2007 12:54 AM

In my experience they would never serve (bring to the main panel)... a residence with high leg delta. But looks like I learn something new every day.

Is this an old business or warehouse converted possibly to a residence or residences?


Would it be possible to post us a picture of the main breaker panel ?

The leg they have painted red that goes out the back bottom of your panel is the identified "high leg". It is 208v to neutral and cannot be used for phase to neutral loads. This is a tricky deal at the main panel so watch your p's and q's when breakering your 120 volt stuff. Make sure that high leg is identified at the breaker panel....if not do it yourself. Use common trip three phase breakers for your 3 phase stuff. Don't try to get resourceful with single pole breakers.

The white wire is your neutral it carries the phase to neutral current in this configuration.... so caution.

Stubbie

SleepnZJ 09-07-2007 09:06 AM

This is a house that was built in the 1950's, It did have a ingroud pool and still has a 3 ton AC unit. I will post more pics when I get a chance later.

Well I am going to have a licensed electrician do most of the electrical work for me. I am going to run a few outlets my self both 120/240. I will probably run the 3 phase outlet me self because I have done 3 phase before at a old job. But installing a new pan, updated breaker box and running the new wires in from the outside I will leave to the pro. I just feel better now that I know what type of service I have for when I start making phone calls.

My big question is since I have a 3 phase and I have a lathe that is 220v 3 phase can I run it on the delta 3 phase? I always though that the 3 phase was 120 degrees apart and had equal voltage on each leg? Wouldn't the 208/120/120 be unbalanced to run directly to the lathe with out balancing the voltage?

Stubbie 09-08-2007 01:11 AM

http://www.bmillerengineering.com/im...a_cntrgrnd.gif

This is a grounded delta... B phase is the high leg (wild leg). The voltages you posted 208/120/120 Are B phase to neutral and A and C phase to neutral in that order. Edit: In your case A phase is the high leg (credit to Duncan B for pointing this out to me). If you look at the diagram the delta is grounded at the midpoint between a and c phases. So the midpoint is 0 volts ... 120 volts from A node and 120 volts from C node. So A phase to neutral is 120 volts and C phase to neutral is 120 volts but B phase to neutral is sqrt 3 x 120 = 208 volts. Also you can see all phases measured to each other are 240 volts apart.

The only way you get the 208,120 and 120 is to carry the neutral to the load.

For 3 phase tools at 240 volts you do not carry the neutral you only run the three phases to the load.

I strongly suggest you let a qualified electrician fool with this configuration it is very tricky and easy to get confused to someone seeing high leg delta for the first time.

Stubbie

frenchelectrican 09-08-2007 01:56 PM

as what other been saying with delta service any change on the service entrance system.

It is the best leave this with the electrician whom deal with delta system because for safety reason there are few thing they have to know how to do this properly and do it in codewise .

again i will remind you please heed what they been warning you with the connections it can get ya by suprise if not carefull especally with wildleg side.

I am multilevel electrician i work just about everything from resdentail to all the way to the industrail level so i can see what the sisuation going on

i know there are some electrician whom work on the resdential area only may not really famuiar with this but as long they read this they can get the idea what going on.

let get back with the wildleg situation the wildleg is not very common used system at all and easyly misunderstood item on delta system and i did see bad side effect with any 120 volt devices hook up with wildleg it do pretty good damage there [ been there and see the aftermath with some pepole whom were not too bright what they done it ]

i will empized it again let the electrician do all the work and get all propely hook up in safe manner


please noted that on older delta system it is common to used to marked in RED for wild leg but current code is marked in ORANGE so that is the extra step you have to watch out on this one

Merci , Marc

buffalonymann 09-15-2007 10:39 AM

You have a 240/120 1 phase.

2-hots
1-neutral
1-mechanical ground

Andy in ATL 09-16-2007 10:02 AM

No he doesn't.:thumbsup:

buffalonymann 09-16-2007 04:20 PM

You people don't have a clue about what he has. I've warned you people about the dangers of what you are doing, but you lack basic electrical knowledge to know it.

:laughing:

Speedy Petey 09-16-2007 04:27 PM

Quote:

Originally Posted by buffalonymann (Post 63299)
You people don't have a clue about what he has. I've warned you people about the dangers of what you are doing, but you lack basic electrical knowledge to know it.

:laughing:

And you lack the basic common sense to admit when you are wrong.

Speedy Petey 09-16-2007 04:29 PM

This picture and this description, and you do not think this is three-phase?????
Amazing. :laughing:

Quote:

Originally Posted by SleepnZJ (Post 61631)
Now I put a volt meter on the wires in the cabinet where the wires come into the hose. The wires go as follows "Red, Black, Black" and a white wire at the bottom of the cabinet which I assume is the ground. When it test across the red and white I get 210 volts, when I test the other two black wires across the white I get 120 volts. When I test across both the blacks I get 240 volts and when I test across either of the blacks to the red I get 240 volts.

http://thumb1.webshots.net/t/52/152/...1pNfGlh_th.jpg

buffalonymann 09-16-2007 04:47 PM

speedy you are not a professional, and not even close to an electrician. Even a monkey can count wires.

News Flash - A 3-phase centered tapped configuration has (4) current carrying conductors.

Like I said to andy, stubbie, and the others who insist this is 3 phase, you people are not qualified to give anybody advice, you're irresponsible, and finally not even smart enough to acknowledge the advice of somebody who was educated in the trade


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