3 PH RESIDENTIAL SERVICE
- Thread starter dixson
- Start date
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pierre
Senior Member
- Location
- Westchester County, New York
Re: 3 PH RESIDENTIAL SERVICE
Where did you get the info that there is a "highleg" with this service... to a dwelling?
All of the residential services that are 3 phase in our area are straight forward - meaning no highlegs.
Where did you get the info that there is a "highleg" with this service... to a dwelling?
All of the residential services that are 3 phase in our area are straight forward - meaning no highlegs.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: 3 PH RESIDENTIAL SERVICE
I don't think the Code has a thing to say about it.
But the Customer Service Department at the serving Power Company might. Might. But I'll just bet it won't matter to them either, but I'd check anyway.
I don't think the Code has a thing to say about it.
But the Customer Service Department at the serving Power Company might. Might. But I'll just bet it won't matter to them either, but I'd check anyway.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: 3 PH RESIDENTIAL SERVICE
Pierre,
I've seen a couple 120 / 240 V four wire three phase residential services in my area.
It's possible.
Pierre,
I've seen a couple 120 / 240 V four wire three phase residential services in my area.
It's possible.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: 3 PH RESIDENTIAL SERVICE
I've worked on several 3 phase services in detatched single family dwellings. They've all had interesting back stories.
The weirdest of my experiences was at a fine old two story 1910 structure, brick exterior, finished "attic", swimming pool in back on the edge of the high bluff above the Mississippi River just west of downtown St. Paul.
The house had two services: </font>
While I was working in the basement, the house began to rumble and the sounds of screams started approaching.
The 14 year old son, having found the secret room behind the hinged attic bath linen closet, had been exploring a builtin set of drawers. The lowest drawer had been stuck and he finally pryed it open to find nothing except a human skull.
Being proud of and delighted by his find, he brought it out to his sister and mother.
They went screaming down the stairs. That was my first day on the job.
The police were called, the skull investigated and determined to be a female in her thirties but nothing came of that, and eventually was returned to the homeowners and the boy built a little shrine for it.
I've worked on several 3 phase services in detatched single family dwellings. They've all had interesting back stories.
The weirdest of my experiences was at a fine old two story 1910 structure, brick exterior, finished "attic", swimming pool in back on the edge of the high bluff above the Mississippi River just west of downtown St. Paul.
The house had two services: </font>
- <font size="2" face="Verdana, Helvetica, sans-serif">Single phase 120 / 240 V 60 A underground. The privately owned underground service lateral was two conductor lead covered (the lead was the neutral) and was on the NE corner of the basement. This service was fed from a transformer half a block to the North.</font>
- <font size="2" face="Verdana, Helvetica, sans-serif">Three phase 240 V 30 A three wire, also underground, located on the WEST side of the basement. This service was fed from a transformer located one and a half blocks to the SOUTHEAST</font>
While I was working in the basement, the house began to rumble and the sounds of screams started approaching.
The 14 year old son, having found the secret room behind the hinged attic bath linen closet, had been exploring a builtin set of drawers. The lowest drawer had been stuck and he finally pryed it open to find nothing except a human skull.
Being proud of and delighted by his find, he brought it out to his sister and mother.
They went screaming down the stairs. That was my first day on the job.
The police were called, the skull investigated and determined to be a female in her thirties but nothing came of that, and eventually was returned to the homeowners and the boy built a little shrine for it.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: 3 PH RESIDENTIAL SERVICE
A three phase high leg service typically has two transformers, one is for single phase. You can use that transformer, I suspect. Check with the POCO.
A three phase high leg service typically has two transformers, one is for single phase. You can use that transformer, I suspect. Check with the POCO.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Re: 3 PH RESIDENTIAL SERVICE
If I remember correctly, all three conductors went through the meter, but I could be wrong, and there was a disconnect that fed the A/C unit. I'm 90% sure the transformer configuration was open Delta.
There are more 3-transformer (closed) Deltas than you might realize. Check the transformer banks overhead when you drive around. If there are 3, and they aren't Y, they're Delta.
A friend of mine had a house that had a 3-phase service. They had the typical overhead service drop: 2 hots and a neutral, probably #2, and a single wire, probably #10, that supplied only the central-A/C.
If I remember correctly, all three conductors went through the meter, but I could be wrong, and there was a disconnect that fed the A/C unit. I'm 90% sure the transformer configuration was open Delta.
That's a generalization that may or may not be true. The 2-transformer, high-leg system you describe is the afore-mentioned open Delta.
There are more 3-transformer (closed) Deltas than you might realize. Check the transformer banks overhead when you drive around. If there are 3, and they aren't Y, they're Delta.
- Location
- Windsor, CO NEC: 2023
- Occupation
- Hospital Master Electrician
Re: 3 PH RESIDENTIAL SERVICE
Al, great story.
I installed a temp once for a "residence" with a 3?, high-leg delta service. It was 200 amp, and we ran 350 AL around...a couple hundred feet to the temp. (Abandoned the high-leg temporarily.)
I say "residence" because the owner was basically building a shop with the footnote of some rooms for his family. I never went to the rough or trim, but I've seen it driving by - it doesn't look like a house. The wife must be thrilled.
Al, great story.
I installed a temp once for a "residence" with a 3?, high-leg delta service. It was 200 amp, and we ran 350 AL around...a couple hundred feet to the temp. (Abandoned the high-leg temporarily.)
I say "residence" because the owner was basically building a shop with the footnote of some rooms for his family. I never went to the rough or trim, but I've seen it driving by - it doesn't look like a house. The wife must be thrilled.
Re: 3 PH RESIDENTIAL SERVICE
I appreciate all the feed back on this situation. The service on the house is existing and in good condition however everything after that is junk. Hence the question of leaving the 3 phase in the meter can. I can't find anything in the code that states the 3 phase needs to enter the house.
I appreciate all the feed back on this situation. The service on the house is existing and in good condition however everything after that is junk. Hence the question of leaving the 3 phase in the meter can. I can't find anything in the code that states the 3 phase needs to enter the house.
frenchelectrican
Senior Member
- Location
- Nord'est Wisconsin et Paris France
Re: 3 PH RESIDENTIAL SERVICE
there are quite few home still use 3 phase service but now days most use single phase but if have exsting true three phase system you have to check the system voltage to make sure you have either 120/240 delta [ including wild leg ] or 120/208 volt most will go with latter now days and i will suggest to check with poco to make sure with the system is ok along the way too.
it is very typically to see 3 phase in size of 200 amp or more now days but i do see few have small as 30or 60 amp 3 phase system in there [ kinda of very rare beast along there]
if you are converting to single phase you have to info the poco about this so they can change the correct connetion on the can if need to
Merci, Marc
there are quite few home still use 3 phase service but now days most use single phase but if have exsting true three phase system you have to check the system voltage to make sure you have either 120/240 delta [ including wild leg ] or 120/208 volt most will go with latter now days and i will suggest to check with poco to make sure with the system is ok along the way too.
it is very typically to see 3 phase in size of 200 amp or more now days but i do see few have small as 30or 60 amp 3 phase system in there [ kinda of very rare beast along there]
if you are converting to single phase you have to info the poco about this so they can change the correct connetion on the can
Merci, Marc
altarengineering
Member
Re: 3 PH RESIDENTIAL SERVICE
As a representitive for a utility, I emphasize the question posed by someone earlier. If you have the option of not bringing the "hi-leg" through the meter, why have it brought to the meter at all. We have several 3 phase houses but most are 120/240. What is the purpose of having the 208 brought to the meter.
As a representitive for a utility, I emphasize the question posed by someone earlier. If you have the option of not bringing the "hi-leg" through the meter, why have it brought to the meter at all. We have several 3 phase houses but most are 120/240. What is the purpose of having the 208 brought to the meter.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: 3 PH RESIDENTIAL SERVICE
altarengineering,
Are you suggesting that the high leg on this existing service should be removed back to transformer? Is there a requirement that you know of for the removal?
altarengineering,
Are you suggesting that the high leg on this existing service should be removed back to transformer? Is there a requirement that you know of for the removal?
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