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#203278 - 09/18/11 12:45 PM Service upgrade concept...Thoughts?  
sparkyinak  Offline
Member
Joined: Jul 2007
Posts: 1,327
Alaska
I am putting together a concept for a project. I don’t see a problem with it but it wouldn’t hurt for other opinions. I am away from the office so I don’t have my resources to check things out (what a way to spend a vacation).

We have a large warehouse that we are planning to convert from 480 delta to 208 wye. There is no 480 loads in the building and there are about a half dozen 30 year old transformers we are paying impedance losses on for no reason. The site use to be on diesel generation.

To minimize impact on the occupants, my concept is:
• Install new MDP next to the old MDP as put of a local utility upgrade.

• From old MDP, feed a temporary transformer that will power the new MDP.

• All new feeders will be piped from new MDP to close as practical to existing panels

• When schedules allow like on weekends, one transformer at a time:
* One transformer at a time will be taken out of service
* Old feeder will be removed.
* New panel replacement as needed.
* New feeder to panel will be finished piping and pulled, then energized

• Demo out remaining of old feeder, set up for next change over during the week

• Once all the old circuits are out of the old MDP, do a service swap and the POCO will retap their tranny for 208.

• Old service will be will be demoed out.

Thoughts?

Last edited by sparkyinak; 09/18/11 12:47 PM.

"Live Awesome!" - Kevin Carosa

Work Gear for Electricians and the Trades

#203281 - 09/18/11 02:56 PM Re: Service upgrade concept...Thoughts? [Re: sparkyinak]  
jay8  Offline
Member
Joined: Jul 2005
Posts: 183
Vancouver, BC
Any reason you cant go with ACWU or Teck for the feeders instead of pipe? It may save on the labour of having to run the conduit then pull every feeder, possibly needing to shutdown the new MDP every weekend when you pull in a new feeder into it. With the cable you can run them all and terminate, lock out each feeder and put a suitable JB on the panel end until ready to energize.

in any case should be some good money on scrap from this.


#203285 - 09/18/11 10:55 PM Re: Service upgrade concept...Thoughts? [Re: jay8]  
sparkyinak  Offline
Member
Joined: Jul 2007
Posts: 1,327
Alaska
Originally Posted by jay8
Any reason you cant go with ACWU or Teck for the feeders instead of pipe?
for the life I me, I'm not sure what these are. There's only one large long pull, the rest are in the same or ajoining room. I like conduits and LB's over gutters and boxes. Looks cleaner although I would consider them as needed


"Live Awesome!" - Kevin Carosa

#203292 - 09/19/11 03:01 PM Re: Service upgrade concept...Thoughts? [Re: sparkyinak]  
mikesh  Offline
Member
Joined: Jun 2006
Posts: 613
Victoria, BC, Canada
The only problem with a multi nation site is the materials change across boarders. I don't think Teck is an approved cable in the USA and ACWU is just wet location AC90 with aluminim conductors. a Jacketed armoured cable suitable for wet locations.
I would try and get all the panel feedeers run to the old panels and energise the new service first then chage them over 1, 2 or all over the week end.I would want the old service turned off asap.


#203295 - 09/19/11 09:55 PM Re: Service upgrade concept...Thoughts? [Re: sparkyinak]  
Scott35  Offline

Broom Pusher and
Member
Joined: Oct 2000
Posts: 2,707
Anaheim, CA. USA
Sparks,

I have a few questions per your Project.

  1. How large is this Building - as in Square Footage?
  2. Are any other Tenants' Services driven from the same Transformer array?
  3. Is the existing 480V Delta Grounded or Ungrounded?
  4. What is the KVA Capacity of the existing Transformer array?
  5. Will your Client have any Motor-Driven Equipment;
    either a single Unit sized 10 HP and +,
    &/or
    multiple 3 + HP Units?
  6. Are there any existing Heatpumps, driven by the 480V System?
  7. Will there be a significant amount of Warehouse Lighting per this T.I.?
  8. Will you need to add Service Laterals between the Transformer Pole and the Service?
  9. What is the Poco charging for the Transformer changeout?
  10. What did your Load Calcs show for the Computed Load?
  11. What size are the SDS Transformers, and are they currently pumping out "too much heat"?
  12. What size is the existing Service Equipment, and is the existing Service Equipment "Smithsonian Institute Worthy"
    (Antiquated)?


I am wondering if the 480V Service might be a better choice overall.

Will check back later today, and see what your answers are.

Lastly... Dude, you are on Vacation!!! Go have fun with your Wife and Family!!! Engineer this Project when the Vacation is over, and you are back in the Office / Field / Meetings / Etc.

Please do not take offense to the latter statements, as they were inserted as a Positive thing only.

-- Scott


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

#203346 - 09/23/11 01:37 PM Re: Service upgrade concept...Thoughts? [Re: Scott35]  
sparkyinak  Offline
Member
Joined: Jul 2007
Posts: 1,327
Alaska
Originally Posted by Scott35
Sparks,

I have a few questions per your Project.

  1. How large is this Building - as in Square Footage? I'm guessing 24,000+
  2. Are any other Tenants' Services driven from the same Transformer array? No
  3. Is the existing 480V Delta Grounded or Ungrounded?
  4. Are any other Tenants' Services driven from the same Transformer array? Grounded
  5. What is the KVA Capacity of the existing Transformer array?
  6. Are any other Tenants' Services driven from the same Transformer array? Not sure but over size for load. Long history
  7. Will your Client have any Motor-Driven Equipment;
    either a single Unit sized 10 HP and +,
    &/or
    multiple 3 + HP Units?
  8. Are any other Tenants' Services driven from the same Transformer array? Nope
  9. Are there any existing Heatpumps, driven by the 480V System?
  10. Are any other Tenants' Services driven from the same Transformer array? Nothing is running on 480v but the transformers
  11. Will there be a significant amount of Warehouse Lighting per this T.I.?
  12. Are any other Tenants' Services driven from the same Transformer array? No
  13. Will you need to add Service Laterals between the Transformer Pole and the Service?
  14. Are any other Tenants' Services driven from the same Transformer array? No because the energy costs it's like $0.30/kWh
  15. What is the Poco charging for the Transformer changeout?
  16. Are any other Tenants' Services driven from the same Transformer array? No. The new transformer that will go in part of a different upgrade and will be a multitap in anticipation of this project
  17. What did your Load Calcs show for the Computed Load?
  18. Are any other Tenants' Services driven from the same Transformer array? I don't know off hand however a PE sized the new tranny for the existing load to include the transformers plus future capacity.
  19. What size are the SDS Transformers, and are they currently pumping out "too much heat"? No and sometime depends on lack of load
  20. What size is the existing Service Equipment, and is the existing Service Equipment "Smithsonian Institute Worthy"
    (Antiquated)? Currently is a 800 amp service but it feeds an entire compound. It's 30 year old I-line. I dont think it's getting replaced as part of the compound upgrade. I'll still putting this together and my paperwork is 3000 miles away


I am wondering if the 480V Service might be a better choice overall. No

Will check back later today, and see what your answers are.

Lastly... Dude, you are on Vacation!!! Go have fun with your Wife and Family!!! Engineer this Project when the Vacation is over, and you are back in the Office / Field / Meetings / Etc. I'm just brainstorming and had a conference call that day. Figured to bounce it other sparks. I work with non electrical govt enginners that couldn't navigate out of a wet paperbag if they fell. I'm actually here for the arrival of my first grandchild. They are inducing my daughter as we speak. I'm just killing time
Please do not take offense to the latter statements, as they were inserted as a Positive thing only. None taken

-- Scott


"Live Awesome!" - Kevin Carosa


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