Need help with a 30 studio apartment complex metering and feeds

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Strombea

Strombea

Senior Member
Location
Prescott, Arizona, USA
We are remodeling an old motel and changing to 30 studio apartments. I Have never worked on anything with more than a 4 pack meter stack, so i want to get as much info as possible.

POCO will supply 2 or 3 separate meter stacks with 800 amps per, or so, - I haven't done calcs yet.
I will have to go underground after metering point to other isolated units in different buildings (probably around 8) because POCO will only allow me 2 metering points but there are 5 separate buildings.

So the question is on multi family dwellings can i share a 4" pipe to a building with 4 sub feeds from meters in it, and upsize and share a neutral between units as to have l quantity of wires in the pipe? does each studio need its own conduit? Does it need to be metal out of the ground? Where do you change from independent wire to romex-type feed wire or do I run pipe into each unit's panel all the way from the meter?

Imagine all the meters divided up mounted on 2 buildings but there are more units in separate buildings that i need to feed from meter on a different building.

Who is the best manufacturer for the meter stacks and distribution cabinets?

I do alot of residential and commercial but nothing ever with this many feeds.

Thanks guys!

BTW motel used to be house metered so the new owners obviously want individual meters.
 
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epimetheus

Member
Watch the required derating due more than 3 current carrying conductors in a raceway.

Sent from my XT1254 using Tapatalk
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Strombea said:
POCO says that they are maxed on transformer dip and can only give us 2 maybe3.

my main question is can I put 3 or 4 100 amp us feeds in the same conduit?
Click to expand...

Sure, but it will cost you more.

Assume you would normally use 3 AWG copper for a 100 amp feed.

Now put four single phase feeds in a single conduit that would be 8 current carrying conductors (CCCs) for the purposes of derating.

Eight CCCs takes a 70% reduction in ampacity so your 3 AWG would now have use a 70 amp breaker max.

To get back to 100 amps you would have to use bigger conductors.

You would end up needing 1 AWG for a 100 amp breaker and of course that means a bigger conduit as well.

I used copper in this example but the same issues are faced with aluminum.
 
I

Iron_Ben

Senior Member
Location
Lancaster, PA
Strombea said:
POCO says that they are maxed on transformer dip and can only give us 2 maybe3.

my main question is can I put 3 or 4 100 amp us feeds in the same conduit?
Click to expand...

I worked for the poco for many years. Still, I'm not certain what "maxed on the transformer dip" means. If they are saying there is a limit to how many 3" or whatever size pipes they want to strap on their pole I get that. That's when you ask them about setting another pole nearby or wherever it's best sited. Even if they want to charge you a thousand bucks or so for the pole that just has to be better and cheaper. We would routinely plan to serve a gang pack of meters on each building: a 4 pack, 6 pack, 20 pack, whatever. These other approaches really strike me as too much commotion and potential for confusion down the road.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Strictly speaking it would be a code violation to locate a meter stack at one location and run more than one feeder from there to a separate building. See part II of article 225.
 
Strombea

Strombea

Senior Member
Location
Prescott, Arizona, USA
Thanks everyone,

i will ill meet with POCO again.

"Transformer dip" is simply what you said too many 4" going up the pole. It is a funky situation and we are discussing a possible surface transformer additional to the pole.

load calcs on a studio is 70amps each

i said 100 for easy math
 
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