Please help!!! Design ideas

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olly

Senior Member
Location
Berthoud, Colorado
Occupation
Master Electrician
Im trying to decide the best way to do this.

I have a 320a service meter main with 2-200a breakers that REA mounted on a pole.

There will be 4 green houses, for growing flowers, not weed.

The closest one is 50' from the pole/meter main

My idea is to mount 2-200 outdoor breaker panels on the closest green house, that will feed sub-panels (100a) breaker panels inside, or outside each greenhouse. If I mount the 100a inside I would need a disconnect on the outside if the panel does not have a main breaker in it right?

The customer wants 3 greenhouses to be feed out of 1 of the 200a panels and just one green house to be feed out of the other 200a panel to provide for future expansion

Would it be better to eliminate the 2-200a breakers and try to find a 320a breaker to eliminate the 2-200a sub panels. Then having a 320a distribution panel on the first green house.

Would you do anything different? I'm trying to make this cost effective and clean.
 

suemarkp

Senior Member
Location
Kent, WA
Occupation
Retired Engineer
Not so sure you can run two 200A feeders to one building, violates article 225 for multiple circuits to a building. Can you do a 200A feeder to one greenhouse, and a 200A feeder to another greenhouse, and then put in 100A feeders from one of those to feed the other two buildings?

If each greenhouse has more than 6 circuits from its first panel, that panel needs a main disconnect. It doesn't matter if the panel is inside (nearest point of feeder entry) or outside. The first panel on the building that feeds things in or on that building is where the disconnect must be located. Panels further in don't need a main unless you're using tap rules.

Using a panel with a 400A main and two 200A feeder breakers is going to cost a lot more than what you have now. If that meter main has two 200A breakers, it may not have bussing to take a larger breaker.
 

olly

Senior Member
Location
Berthoud, Colorado
Occupation
Master Electrician
Green house lay out

Green house lay out

Is there any codes stating how many outlets you have to have in a green house? Or any other weird codes that apply to green houses?
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Not so sure you can run two 200A feeders to one building, violates article 225 for multiple circuits to a building. Can you do a 200A feeder to one greenhouse, and a 200A feeder to another greenhouse, and then put in 100A feeders from one of those to feed the other two buildings?

If each greenhouse has more than 6 circuits from its first panel, that panel needs a main disconnect. It doesn't matter if the panel is inside (nearest point of feeder entry) or outside. The first panel on the building that feeds things in or on that building is where the disconnect must be located. Panels further in don't need a main unless you're using tap rules.

Using a panel with a 400A main and two 200A feeder breakers is going to cost a lot more than what you have now. If that meter main has two 200A breakers, it may not have bussing to take a larger breaker.
I do not think that the limitation on feeders applies to a feeder which just passes through and does not serve any loads at that building. Even putting a disconnect there should be OK as long as it is outside the building.
 

kwired

Electron manager
Location
NE Nebraska
Sounds like you need to determine the load for each building before you do much of anything else.

Is there any significant load that consists of "grow lights"? If not the load is probably somewhat minimal, but will still depend on actual size for just a general lighting load at very least.

If POCO provided the meter with two mains - some AHJ still require you to treat your run(s) from that point as if service conductors, because POCO could change the equipment to something without overcurrent protection next time an upgrade or repair/replacement is necessary.
 
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