Multi-Structure and Multi-Panel Grounding and Bonding

[R_Matt17]

I would greatly appreciate some input and see if someone can answer my questions on a house service that myself and another electrical engineer are designing and installing in Ohio (Current Code NFPA70 2017). I have a home and barn which are fed from a common utility pad mount transformer. There is 3 separate 200A disconnects to the house, each feeding a separate 200A panel, and one 200A disconnect for a 200A barn panel, fed parallel from an 800A utility service. Due to lead times and availability, the 4 disconnect option was the only means feasible for this installation to meet the deadline. Since the first means of disconnect is the service pedestal, the house neutral-ground bond and barn neutral-ground bond are at the pedestal in the disconnects. The service pedestal sits 100 feet from the house.

My questions:

• Should the house and barn share or have separate ground rods? Are these ground rods adequate?
• Is this bonding correct?
• Should the 3 house panels all share the ufer ground ? Should only one tie into the ufer?

Below are images of the installation.

https://imgur.com/a/TRrD9Ro

 

[augie47]

IMO, a bigger problem is that under the 2017 NEC, you are limited to one feeder to a structure (225.30)

 

[R_Matt17]

IMO, a bigger problem is that under the 2017 NEC, you are limited to one feeder to a structure (225.30)

Is this in reference to 225.30 (B)?

 

[augie47]

My post was directed to 225.30 in general
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.........................
. "B" would allow it "by special permission".

 

[R_Matt17]

My post was directed to 225.30 in general
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.........................
. "B" would allow it "by special permission".

I see, my apologies. To clarify, under the "B" Special permissions (Local and Utility approved), would the existing grounding and bonding be correct? This house service is so large due to elevators, HVAC, pool/spa heating (90A of heating alone), multiple kitchens, and extensive appliances.

 

[augie47]

At your service point (200 amp disconnects) 250.64(D) would apply,.
Per that Section you have a few options including a connection to a common location ahead of the disconnects; a GEC from each to a common grounding electrode; a common grounding electrode conductor tapped to each enclosure, etc,.
Your drawing depicts an acceptable manner (POCO will likely wanty a GEC connection to the meter)

 

[R_Matt17]

At your service point (200 amp disconnects) 250.64(D) would apply,.
Per that Section you have a few options including a connection to a common location ahead of the disconnects; a GEC from each to a common grounding electrode; a common grounding electrode conductor tapped to each enclosure, etc,.
Your drawing depicts an acceptable manner (POCO will likely wanty a GEC connection to the meter)

That was my interpretation as well and I agree, I am missing my meter GEC in the drawing.

 

[Engser18]

Why would you do that? You can set panel at the barn and 3 panel at the house as services instead of feeder.

If you are doing you way, one electrode system would be good at the rack. You would need another electrode system at the barn and the house. You are also running the EGC with each feeder. And these panels should have MCB.

 

[electrofelon]

Why would you do that? You can set panel at the barn and 3 panel at the house as services instead of feeder.

If you are doing you way, one electrode system would be good at the rack. You would need another electrode system at the barn and the house. You are also running the EGC with each feeder. And these panels should have MCB.

Yeah I agree, I keep conductors as service conductors whenever possible. Putting a service disconnect at a pedestal is usually pointless and just adds cost, unless required by local rules or POCO of course. See 230.40 exception #3

 

[Buck Parrish]

We avoid using a pedestal on a luxury home. They tend to age much quicker then the house. They call it an H mount in Indiana.
Maybe if you put a roof on it.

 

[R_Matt17]

Yes, the local utility requires all home services to be mounted on a pedestal regardless of size. I can actually post the utility requirements at some point as well. This home is enormous and with the aesthetic, they did not want a pedestal directly next to the house. I'll post the approved drawing in the near future. One grounding system (triad) at the pedestal and the ufer at the house, and a ground rod at the barn. All panels have an MCB to satisfy a readily available means of disconnect inside the home. Each conduit has an EGC and grounds and neutrals are kept separate after the pedestal. IMO these types of installations are going to become more and more common place as utilities begin adopting pedestals and meter/disconnect combo requirements and as the power demands of homes continue to increase. Ohio has steadily moved towards meter/disconnects and pedestals.

 

[R_Matt17]

We avoid using a pedestal on a luxury home. They tend to age much quicker then the house. They call it an H mount in Indiana.
Maybe if you put a roof on it.

I totally agree, however, in this part of Ohio the utility requires a pedestal. We do our pedestal out of treated lumber and AZEK board as a backer to make the installation a little cleaner. Obviously NEMA 3R equipment.