400 amp service

[timdumars]

I currently have a 400 amp meter pedestal with 200 A going to one building. It seems now that the buildings gonna require 400 A alone so I need to run a separate feeder to a new sub panel inside. Do my panels have to be grouped together or can they be on opposite ends of the building? There’s...

 

[timdumars]

The pedestal with the 2-200 amp breakers is about 120 feet away

 

[Dennis Alwon]

You need to group the disconnects. Depending on what code you are using you may not be allowed to run 2 feeders to one building

 

[augie47]

What Dennis says !
(Based on an unreliable search, Idaho is on the 207 Code in which case two feeders to one building would not be allowed)

 

[kwired]

You need to group the disconnects. Depending on what code you are using you may not be allowed to run 2 feeders to one building

Was there changes in either 2020 or 2023 regarding this? You basically never could run multiple feeders to a one building as a general rule.

You can have parallel conductors as the feeder however and still can have up to six disconnecting means at the building.

 

[augie47]

Change in 2020

 

[timdumars]

So if I parallel my second 200 amp feeder I could put 2-200 amp disconnects on the outside of the building together and that would make it legal to have the 400 amps there? It’s all off one meter at the 400 amp pedestal.

 

[augie47]

2017:
225.30 Number of Supplies. A building or other structure that is served by a branch circuit or feeder on the load side of a service disconnecting means shall be supplied by only one feeder or branch circuit unless permitted in 225.30(A) through (E). For the purpose of this section, a multiwire branch circuit shall be considered a single circuit.

 

[Dennis Alwon]

So if I parallel my second 200 amp feeder I could put 2-200 amp disconnects on the outside of the building together and that would make it legal to have the 400 amps there? It’s all off one meter at the 400 amp pedestal.

What code cycle are you on? Coming from one location to 2 different locations is not a parallel run. You would have to parallel the run and tap to each panel. I believe that is why they made the change.

225.30 Number of Supplies.
A building or other structure that is served by a branch circuit or feeder on the load side of a service disconnecting means shall be supplied by only one feeder or branch circuit unless permitted in 225.30(A) through (F). For the purpose of this section, a multiwire branch circuit shall be considered a single circuit.
Where a branch circuit or feeder originates in these additional buildings or other structures, only one feeder or branch circuit shall be permitted to supply power back to the original building or structure, unless permitted in 225.30(A) through (F).

(A) Special Conditions.
Additional feeders or branch circuits shall be permitted to supply the following:

• (1)
  Fire pumps
• (2)
  Emergency systems
• (3)
  Legally required standby systems
• (4)
  Optional standby systems
• (5)
  Parallel power production systems
• (6)
  Systems designed for connection to multiple sources of supply for the purpose of enhanced reliability
• (7)
  Electric vehicle charging systems listed, labeled, and identified for more than a single branch circuit or feeder
• (8)
  Docking facilities and piers

(B) Common Supply Equipment.
Where feeder conductors originate in the same panelboard, switchboard, or other distribution equipment, and each feeder terminates in a single disconnecting means, not more than six feeders shall be permitted. Where more than one feeder is installed in accordance with this section, all feeder disconnects supplying the building or structure shall be grouped in the same location, and the requirements of 225.33 shall not apply. Each disconnect shall be marked to indicate the load served.

(C) Special Occupancies.


By special permission, additional feeders or branch circuits shall be permitted for either of the following:

• (1)
  Multiple-occupancy buildings where there is no space available for supply equipment accessible to all occupants
• (2)
  A single building or other structure sufficiently large to make two or more supplies necessary

(D) Capacity Requirements.


Additional feeders or branch circuits shall be permitted where the capacity requirements are in excess of 2000 amperes at a supply voltage of 1000 volts or less.

(E) Different Characteristics.


Additional feeders or branch circuits shall be permitted for different voltages, frequencies, or phases, or for different uses such as control of outside lighting from multiple locations.

(F) Documented Switching Procedures.


Additional feeders or branch circuits shall be permitted to supply installations under single management where documented safe switching procedures are established and maintained for disconnection.

 

[timdumars]

You need to group the disconnects. Depending on what code you are using you may not be allowed to run 2 feeders to one building

I spoke to my inspector and he said as long as the building is considered residential then it was fine but if it was commercial then it would not. I was surprised because I thought it would probably be the other way around.

 

[kwired]

I spoke to my inspector and he said as long as the building is considered residential then it was fine but if it was commercial then it would not. I was surprised because I thought it would probably be the other way around.

It shouldn't matter if it is residential or not. This rule applies to all occupancies.

 

[Dennis Alwon]

I spoke to my inspector and he said as long as the building is considered residential then it was fine but if it was commercial then it would not. I was surprised because I thought it would probably be the other way around.

Not sure where that came from. What code are you using? 2017 doesn't allow 2 feeders at all but the 2020 does under certain conditions

225.30(B) Common Supply Equipment.

Where feeder conductors originate in the same panelboard, switchboard, or other distribution equipment, and each feeder terminates in a single disconnecting means, not more than six feeders shall be permitted. Where more than one feeder is installed in accordance with this section, all feeder disconnects supplying the building or structure shall be grouped in the same location, and the requirements of 225.33 shall not apply. Each disconnect shall be marked to indicate the load served.