400 amp residential feeders using parallel 1/0s??

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shortcircuit2 said:
Violation of 225.30
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Outright, yes. However, 225.30(B)(2) opens up a possibility, however thin that may be. The only thing in question is probability. Just need AHJ blessing. Granted, it may not be an intended possibility for this size building... but it is not written that way. It goes without saying, but you'll never know unless you ask.

And given the meter main named is 2/200 only, what other option is there? Does Milbank offer a 400A 4-pole breaker?
 
And given the meter main named is 2/200 only, what other option is there? Does Milbank offer a 400A 4-pole breaker?
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They do not. I called Milbank today and asked if the two 200 amp breakers were parallel per 240.8 and they said yes.
 
jzadroga said:
They do not. I called Milbank today and asked if the two 200 amp breakers were parallel per 240.8 and they said yes.
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So they are listed as a single unit?

Even so, you're still back to using full size EGC in each conduit. The only leniency on that is going to be by special permission under section I mentioned earlier.
 
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The supply side of the 2 200 amp breakers is in parallel. You can not connect the load side of the breakers in parallel no matter what anyone at Milbank says. I also don't think they intended to say you could connect the breakers in parallel.

I have used many class 320 meter mains with a single 400 amp breaker so they are definitely available. You don't find much Milbank in my area so I don't know what they have but Bline (Circle AW) makes them.

In my opinion there is no way to make a reasonable argument that a more that one supply is necessary for a building requiring a 400 amp single voltage supply. If the supply needed to be greater than 4000 amp then I can see it being acceptable. Anything less can easily be done with standard equipment.
 
OK, I got bad info from Milbank. You guys are correct. When I emailed them for written confirmation the tech replied they are for two separate 200 amp supply's. Id be fine if the utility didn't require the disconnect at the meter.
I also met with the inspector and he is fine with the two separate feeders. Each feeder supplying one panel in the same location. #4 EGC is fine in each conduit.

Thanks for the recommendation for the 400 amp meter main. Does anyone have other manufacturers that make them?
 
Here is what the 2010 National Grid spec book says...

5.1.7.2 Meter pedestals are free-standing units intended to be mounted outdoors on a concrete pad in
conjunction with underground wiring. If a free-standing meter pedestal is used, it shall extend a minimum
below the finished grade or ground line with stabilizing means extending below the frost line to ensure
that the meter mounting stays in a plumb position. See Section 7 for further details. Meter pedestals for
self-contained metering must be listed devices and shall also incorporate circuit breakers, but these are
not intended to replace the service disconnecting means required at the building.


Here is a link to National Grids requirements...

https://www.nationalgridus.com/niagaramohawk/non_html/constr_esb750.pdf
 
shortcircuit2 said:
Here is what the 2010 National Grid spec book says...

5.1.7.2 Meter pedestals are free-standing units intended to be mounted outdoors on a concrete pad in
conjunction with underground wiring. If a free-standing meter pedestal is used, it shall extend a minimum
below the finished grade or ground line with stabilizing means extending below the frost line to ensure
that the meter mounting stays in a plumb position. See Section 7 for further details. Meter pedestals for
self-contained metering must be listed devices and shall also incorporate circuit breakers, but these are
not intended to replace the service disconnecting means required at the building.


Here is a link to National Grids requirements...

https://www.nationalgridus.com/niagaramohawk/non_html/constr_esb750.pdf
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Yeah thats what I read. Sounds pretty vague to me. What I was suggesting/asking was if his national grid rep/designer said he needed a disco there or not. There are lots of little things in the spec book that in practice aren't required or enforced.
 
I have talked with the engineers from national grid that look at the install before they send the line crew. They want the disconnect. They say its for the safety of the meter people in case they need to remove the meter. I question that because they don't require the disconnect if the meter is on the house. Whats the difference to the meter person? If they can pull the meter without the disco at the house why is a remote meter different?

Anyways If I want it hooked up I have to have the disconnect. They require it for any remote meter of any amperage. :sick::sick::sick::sick::sick::sick:
 
jzadroga said:
I have talked with the engineers from national grid that look at the install before they send the line crew. They want the disconnect. They say its for the safety of the meter people in case they need to remove the meter. I question that because they don't require the disconnect if the meter is on the house. Whats the difference to the meter person? If they can pull the meter without the disco at the house why is a remote meter different?
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A couple factors are in play. Just as typical disconnects are not rated for disconnect under load, meters are no different. It's also an extra layer of assurance that nothing on the load side will backfeed the socket while the meter is removed. For example, it's not unheard of for a home owner to backfeed the system with a generator and not have the required interlock.
 
jzadroga said:
I have talked with the engineers from national grid that look at the install before they send the line crew. They want the disconnect. They say its for the safety of the meter people in case they need to remove the meter. I question that because they don't require the disconnect if the meter is on the house. Whats the difference to the meter person? If they can pull the meter without the disco at the house why is a remote meter different?

Anyways If I want it hooked up I have to have the disconnect. They require it for any remote meter of any amperage. :sick::sick::sick::sick::sick::sick:
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My guess, is if the meter is away from the house they want customer to be able to disconnect the feed from meter to the house without having to call POCO, this makes their maintenance responsibilities end at the metering equipment.
 
Talked to a National grid engineer to find out why the disconnect. He said it protects the meter person if they install a meter and the load side of the underground has a fault, they wont end up creating a dead short. The person can install the meter and turn on the breaker. If the customers underground has a fault the breaker will trip, saving the meter person from an arc. I guess if the meter is at the house they figure its less likely to have a fault.
 
jzadroga said:
Talked to a National grid engineer to find out why the disconnect. He said it protects the meter person if they install a meter and the load side of the underground has a fault, they wont end up creating a dead short. The person can install the meter and turn on the breaker. If the customers underground has a fault the breaker will trip, saving the meter person from an arc. I guess if the meter is at the house they figure its less likely to have a fault.
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Sounds to me like they couldn't think of a better answer. If they want no load when installing/removing a meter they will require disconnecting means for all meters.

Some POCO do want this on over 150 volts to ground systems, some may want it on over 200 amps or something like that, but they have a better reputation if they have some consistency. Some do have a plug in test module that tells them if there is a fault that their technician uses before plugging in a meter. If there is a fault indicated - no meter is installed until the problem is cleared.
 
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