Can anyone suggest tech or cost improvements to this 1000 kVA design???

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dionysius

Senior Member
Location
WA
Here is my design for supplying 1000 kVA of separately metered 3 phase power to expand an existing paper mill.

Please point out any suggestions or savings possible. Could I use smaller gauge neutrals between XFR and Switchboard to save cost???

Is Cu definitely a better way to go than Al between XFR and Switchboard???? If so then why since it is more expensive. But pulling Al thru 3" conduits is a concern.
 

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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Nothing wrong with using aluminum. If you think the conduit is small enough that it's going to make any real difference in such a short pull, make the conduit bigger.

I would also say this. Most of the time I have found that running parallel conductors in Copper is more cost-effective than running one big conductor. I don't use aluminum so I don't know if that also applies to aluminum but you might want to see if 2 1/0 conductors in parallel is less than a single 250.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
one thing that might save you some money would be to use MLO remote panels.

My experience with the difference in price between MLO panels and panels with a main suggests sometimes it is actually less money to buy one with a main. That is just the way they get priced up at the supply house.
 

tw1156

Senior Member
Location
Texas
Distribution Board?

Distribution Board?

Tagging on to Petersonra's comment, have you evaluated using a Distribution Panelboard in lieu of the Switchgear? Since you're at 1200A, a Distribution panelboard with 6 Disconnect rule is an option, but check your local codes as sometimes a Main is required by Fire Dept, POCO, City, etc.
 

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
Minor thing but I think it is consistent across the country. In this area, aluminum is generally stocked in XHHW not THWN. so you may want to modify for that. Vice Versa for the copper. THWN is cheaper than XHHW. Although both are stock.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Minor thing but I think it is consistent across the country. In this area, aluminum is generally stocked in XHHW not THWN. so you may want to modify for that. Vice Versa for the copper. THWN is cheaper than XHHW. Although both are stock.

Incidentally, we have found that it is generally cost effective to purchase larger size conductors from Internet sources rather than the local supply house, even if we have to pay shipping. None of our local supply houses stock much in the way of larger sizes of wire anyway.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Tagging on to Petersonra's comment, have you evaluated using a Distribution Panelboard in lieu of the Switchgear? Since you're at 1200A, a Distribution panelboard with 6 Disconnect rule is an option, but check your local codes as sometimes a Main is required by Fire Dept, POCO, City, etc.

I don't have much experience with actual switchgear but switchboards often seem to be cost competitive with panel boards at these sizes.

You might also want to look at an MCC section. I know this sounds a little odd but MCCs can sometimes be a cost effective substitute for panelboards and/or switchboards. Pricing for this kind of stuff is all over the place so it is really hard to give you any guidance.
 

dionysius

Senior Member
Location
WA
Some prices.......

Some prices.......

Thank you all for the great feedback. Keep it coming. I hope the picture is legible.

Any comments on my grounding?? There is a rebar Ufer close by which I will use.

The Switchboard is $10,000.

The PUD gets circa $40,000 for (1) a pole to extend from an existing pole by 40 ft (2) the XFR (3) the vault (4) the primary side wiring (5) the meter.
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Thank you all for the great feedback. Keep it coming.

Any comments on my grounding?? There is a rebar Ufer close by which I will use.

The Switchboard is $10,000.

The PUD gets circa $40,000 for (1) a pole to extend from an existing pole by 40 ft (2) the XFR (3) the vault (4) the primary side wiring (5) the meter.

If this is an SDS, the code actually requires you to use the nearest of the metal water pipe GE or structural metal GE unless they are not available. 250.30(A)(4).

OTOH, if by PUD you are referring to a utility, maybe this is a service. However that would seem to violate the rule on having just one service.
 

pcanning87

Member
Location
New York
As other people have said, I'd definitely use parallel aluminum instead of copper and possibly use MLO sub panels.

If there's a main 1200A breaker, the costs of that can also vary with the functionality (programmability).


Sent from my iPhone using Tapatalk
 

dionysius

Senior Member
Location
WA
As other people have said, I'd definitely use parallel aluminum instead of copper and possibly use MLO sub panels.

If there's a main 1200A breaker, the costs of that can also vary with the functionality (programmability).


Sent from my iPhone using Tapatalk

There is no 1200A breaker. It would be nice to have it. Too expensive and not needed per code in this case.

I am now asking myself if Al will be too stiff and bulky for 3" conduits which are already in cement. There are 3 90 degree turns in the run.
 
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JFletcher

Senior Member
Location
Williamsburg, VA
There is no 1200A breaker. It would be nice to have it. Too expensive and not needed per code in this case.

I am now asking myself if Al will be too stiff and bulky for 3" conduits which are already in cement. There are 3 90 degree turns in the run.

As long as the conduit fill isnt violated I see no reason to use Cu over Al, unless the job specs call for it.

A tugger and lots of lube are your friends.
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
Any comments on my grounding?? There is a rebar Ufer close by which I will use.
That's fine but if this is a service you will have to use all available GE's, building steel, water piping, (if it meets the requirement of being a GE) existing ground rings, etc.....


Roger
 
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