DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   Electrical (http://www.diychatroom.com/f18/)
-   -   3-phase to residential garage in Phoenix? (http://www.diychatroom.com/f18/3-phase-residential-garage-phoenix-160336/)

mpoulton 10-16-2012 10:55 PM

3-phase to residential garage in Phoenix?
 
I just bought a house in Phoenix, and it's in an old neighborhood where some homes have high-leg open delta services for 3-phase air conditioners. The overhead utility easement is on the alley along my back property line, and there is an open delta transformer bank on the pole next to my property. 3-phase secondary runs past my lot, but my mid-span drop is only single phase. It's nominally a 200A service but the POCO conductors are way undersized for that.

The back yard is pretty deep - probably about 65 feet from the house to the property line. I want to build a detached garage and shop at the back of the lot. It will probably be 24' wide X 30' deep. This is directly underneath my service drop, so that will have to be moved. What I think I want to do is move the service equipment to the new garage, and then feed the house as a subpanel off the garage service. And I REALLY want 3-phase for the shop.

Questions:

- Does anyone know if APS will provide a new high leg service like this, or do they no longer offer the option? Their website doesn't have any info.

- How would you configure the service equipment? 3-phase fused disco with both panels on the load side? 3-phase main breaker panel with feed-through lugs to the house? Both panels as service-entrance equipment directly off the meter (not sure if this is allowed - didn't look it up yet)? Something else?

- Any other ideas or suggestions for this project?

frenchelectrican 10-16-2012 11:12 PM

Quote:

Originally Posted by mpoulton (Post 1032388)
I just bought a house in Phoenix, and it's in an old neighborhood where some homes have high-leg open delta services for 3-phase air conditioners. The overhead utility easement is on the alley along my back property line, and there is an open delta transformer bank on the pole next to my property. 3-phase secondary runs past my lot, but my mid-span drop is only single phase. It's nominally a 200A service but the POCO conductors are way undersized for that.

I do not know how many homes in that area which that is served with delta transfomer set up if none of any home used them then it possible you can use it but you will have to check with the POCO engineer on this to see if that is festiable due many of the home which I heard and I know one member in other fourm say most useally converted to single phase and ditch the three phase system but very few stay on three phase.

The back yard is pretty deep - probably about 65 feet from the house to the property line. I want to build a detached garage and shop at the back of the lot. It will probably be 24' wide X 30' deep. This is directly underneath my service drop, so that will have to be moved. What I think I want to do is move the service equipment to the new garage, and then feed the house as a subpanel off the garage service. And I REALLY want 3-phase for the shop.

Questions:

- Does anyone know if APS will provide a new high leg service like this, or do they no longer offer the option? Their website doesn't have any info.

Mine answer will cover the upper comment as I posted above and I do not know how far the Phoneix POCO will deal with this.

And I am pretty sure but not 100 % on this one but the APS may not allowed any more new customer on delta system unless that have exsting installment then they can leave it alone otherwise the only other system you can able use is Wye system which the POCO will reconferated the transfomer ( belive or not there were few case they can run single phase plus three phase at the same time from that set of transfomer )



- How would you configure the service equipment? 3-phase fused disco with both panels on the load side? 3-phase main breaker panel with feed-through lugs to the house? Both panels as service-entrance equipment directly off the meter (not sure if this is allowed - didn't look it up yet)? Something else?

- Any other ideas or suggestions for this project?

I can go either way but the safest way is use the main breaker and you can use the takeoff breaker or subpanel main breaker at the main panel which you can run single phase while you can keep the three phase at the garage panel ( unless you did snag a legit wye supply then all by the means use it. )

I am pretty sure there are other members may chime in more details on this so just hang on tight they will come up a answer or deux.

Merci,
Marc

joecaption 10-17-2012 11:07 AM

My question is what type equipment you could be using that even needs 3 ph.
By far most are single phaze unless there commercial grade.

mpoulton 10-17-2012 11:56 AM

Quote:

Originally Posted by joecaption (Post 1032603)
My question is what type equipment you could be using that even needs 3 ph.
By far most are single phaze unless there commercial grade.

Commercial grade.

I want to finish out my metalworking shop with a good lathe and mill, and most of those that are available used are old commercial units with 3-phase motors. I also already have some 3-phase equipment, including a giant laser.

brric 10-17-2012 03:05 PM

The POCOs i'm familiar with will provide almost any service you want as long as you write them a large enough check.

micromind 10-17-2012 06:42 PM

Around here, a 'Staking Engineer' is the person who would determine what type and size of service the utility will supply. Just call the utility and say you're looking at some new 3 equipment and need to know if they'll supply a 3 service for it.

When I built my house 16 years ago, I asked for a 120/208 3 wye service. All 4 12.5KV lines were nearby, it cost me $3600 vs. $1700 for single phase.

Rob

frenchelectrican 10-17-2012 11:27 PM

Quote:

Originally Posted by mpoulton (Post 1032625)
Commercial grade.

I want to finish out my metalworking shop with a good lathe and mill, and most of those that are available used are old commercial units with 3-phase motors. I also already have some 3-phase equipment, including a giant laser.

The key word is laser cutting unit that denfinite need a legit true three phase supply not converted or manufacted third leg supply due the supply and it set up on laser is very senstive with power supply.

Most three phase motour which they are wired on 240 volts can run on 208 volts without major issue if not overloaded ( few case you will see the nameplate say " useable on 208 volts " ) and some case you will see the number stamped " 208-230 " that means it can run either wye or delta supply with out a issue.

But just be aware the POCO may ask you the load demand figures so they can set up proper transfomer.

The smallest three phase transfomer they can feed from POCO side is 45KVA ( triple 15 KVA cans ) but 75 KVA is most common and with 75 Kva rating you will have no issue with 200 amp service on that size at all.

Merci,
Marc

mpoulton 10-18-2012 04:01 AM

There's already 240V high leg service at the pole (open delta transformer bank), and almost all my load is 120/240V 1ph, so I won't ask for a wye service. The high leg transformer is only a 10KVA, but the 120/240 transformer is 50KVA. This serves quite a few houses. So I think I will be pretty limited on how much 3ph load I can have, but I don't need much. Just enough for maybe a 10HP motor or the 15kW laser power supply. That's only 25A or so on the high leg max.

I have a call in to my regional service engineer, and he'll be able to say whether they will give me 3ph or not.


All times are GMT -5. The time now is 04:27 PM.


Copyright 2003-2014 Escalate Media LP. All Rights Reserved