Help with 400 A resi service

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Customer turned his house in to adult care home so need to upgrade to 400. Got 400A service attached to shop with 2 200 A disc one for the shop one for house 70feet away. Also got 3 inch PVC to the house. Poco says 600A out of the question so please input on the best way on getting it done. Thank you
 
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augie47

Moderator
Staff member
Location
Tennessee
I'd have to agree with ceb58. Step 1 is a load calculation. How do you know you need 600 amp ? If you show the need I can't imagine POCO not providing it.
If you only need 400 amps, then you could use your existing 400 amp service to the garage and route a 400 amp feeder to the house thru the existing 3".
(at one time you might have been able to run two 200 amp feeders but 225.30 prohibits that)
 
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I'd have to agree with ceb58. Step 1 is a load calculation. How do you know you need 600 amp ? If you show the need I can't imagine POCO not providing it.
If you only need 400 amps, then you could use your existing 400 amp service to the garage and route a 400 amp feeder to the house thru the existing 3".
Customer stated that he would like to keep 200A to shop for future needs but as of now all the buildings do not calculate even close to 400A
 

augie47

Moderator
Staff member
Location
Tennessee
Yep. POCO isn't wild about "future".
Leave his 200 at the garage, add a 400 there feeding the house and feed them from the existing meter socket. Not ideal, but with two service disconnect your service conductors (to the meter) only have to meet the calculated load.
If and when his load increases he can deal with POCO and you about a new meter socket and riser or lateral.

(Here if he's converting a residence to an adult care home his electrcial problems will be insignificant to other governmental problems :) )
 
Yep. POCO isn't wild about "future".
Leave his 200 at the garage, add a 400 there feeding the house and feed them from the existing meter socket. Not ideal, but with two service disconnect your service conductors (to the meter) only have to meet the calculated load.
If and when his load increases he can deal with POCO and you about a new meter socket and riser or lateral.

(Here if he's converting a residence to an adult care home his electrcial problems will be insignificant to other governmental problems :) )
If I feed the house with 400A and the shop with 200A from 400A meter isn't there possibility of overcurent
 

augie47

Moderator
Staff member
Location
Tennessee
If I feed the house with 400A and the shop with 200A from 400A meter isn't there possibility of overcurent
There is that possibility--furure, but there always is when you are feeding anything other than a main breaker/fuse panel.
If that's what the customer wants and you can't "make" POCO increase unless needed.
Best you can do is be sure homeowner notififys you or POCO of significant load increases. If you have 400 amp service conductors and they exceed that, voltage drop may give a clue.
The potenial overload is most likely outside so thats a plus :grin:
 

augie47

Moderator
Staff member
Location
Tennessee
My guess.. change the 200 at the garage feeding the house to a 400 and add a 400 at the house or group another 200 with the existing.
 

kwired

Electron manager
Location
NE Nebraska
I'd have to agree with ceb58. Step 1 is a load calculation. How do you know you need 600 amp ? If you show the need I can't imagine POCO not providing it.
If you only need 400 amps, then you could use your existing 400 amp service to the garage and route a 400 amp feeder to the house thru the existing 3".
(at one time you might have been able to run two 200 amp feeders but 225.30 prohibits that)
If you make the two 200 amps into one 400 amp parallel by connecting them together at the load end it is now one (400 amp) feeder and then split into 2 (or up to 6 allowed) disconnects at load end. 225.33

Also consider if you do not feed the house from the load side of the shop service it is still service equipment at both locations.
This could save on a 400 amp switch and separate grounded and grounding conductors, unless someone can point out why it would be required to feed the house from the load side of the shop service.
 

augie47

Moderator
Staff member
Location
Tennessee
kwired, that's a good point. I overlooked it as local POCO won't allow a line to a separate structure from the meter without OCP, but Code does.
He could feed from the shop meter, UG to the house and feed the house service equipment.
 

kwired

Electron manager
Location
NE Nebraska
kwired, that's a good point. I overlooked it as local POCO won't allow a line to a separate structure from the meter without OCP, but Code does.
He could feed from the shop meter, UG to the house and feed the house service equipment.
I can only ask why once past the meter why is anything the business of the POCO. Most of them around here no longer have a say in what happens past the meter and for the most part do not care either that is for the electricians and inspectors to worry about.
 
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