400 Amp Meter Main

[jap]

The Power Company out in the county not under local inspection provides combo meter mains.
On the 400 Amp Combo.They come with (2) 200 Amp 1ph Feeder Breakers.(Not 1 400).

They are telling the customer that these can be used for 400 Amp Services and typically they are for
(2) Seperate 200 Amp MLO Panels)

But.

The Customers and electricians that dont know any better are thinking that they can install a Single 400 AMP Panel and take a feed from each 200a breaker in the Meter/Main to the single 400a Panel.

Hearing this floored me.
But off the top of my head I could see where someone could actually do this and never know it was wrong.

 

[suemarkp]

Is there anything wrong with the concept? I think the only missing detail is that the 400A panel would need double lugs to handle the parallel feeder. Other than that, you need to install parallel conductors per the rules and worry about derating if all of these are stuffed into 1 conduit. If they are placing two conductors into a single termination listed for only 1 conductor, then that is a possible problem.

I'm not sure how much I'd fear a lug not listed for 2 conductors. Just because it isn't listed for it doesn't mean it won't work well. But I don't have enough experience with double lugging to know if that is a bad idea or not.

What would floor me is the cost. A 400A panel usually costs a lot more than two 200A ones.

 

[texie]

Is there anything wrong with the concept? I think the only missing detail is that the 400A panel would need double lugs to handle the parallel feeder. Other than that, you need to install parallel conductors per the rules and worry about derating if all of these are stuffed into 1 conduit. If they are placing two conductors into a single termination listed for only 1 conductor, then that is a possible problem.

I'm not sure how much I'd fear a lug not listed for 2 conductors. Just because it isn't listed for it doesn't mean it won't work well. But I don't have enough experience with double lugging to know if that is a bad idea or not.

What would floor me is the cost. A 400A panel usually costs a lot more than two 200A ones.

I think you are missing the point of feeding one panel with 2 breakers in parallel.
But I'm with you on the 400 amp panel. Even if they had a proper 400 amp breaker and feeder, who puts a400 amp panel in a house? One would need to go from two, simple, 200 amp load centers to a full blown panelboard at 5 times the cost. Am I sure I am understanding the OP correctly?

 

[fmtjfw]

Generally not according to code

Generally not according to code

240.8 Fuses or Circuit Breakers in Parallel. Fuses and circuit breakers shall be permitted to be connected in parallel where they are factory assembled in parallel and listed as a unit. Individual fuses, circuit breakers, or combinations thereof shall not otherwise be connected in parallel.

This is normally like the 4 breaker 200Amp main seen on some panels. It has 2 line lugs and engages 4 load bus connections.

The scheme with two separate 2-pole breakers and two parallel 200Amp feeders connected to a single 400A panel appears to violate the Code.

On the other hand, according to the laws of physics, it is probably safer than a 400Amp breaker feeding paralleled 200Amp conductor feeder.

Who said the Code is always logical? Maybe a good change request for 2017 NEC.

 

[fmtjfw]

Bragging rights!

Bragging rights!

A $1500 400A panel might give you bragging rights with your fellow McMansion Buddies.

 

[fmtjfw]

Bragging rights! --2--

Bragging rights! --2--

I once knew a Master Electrician who bragged that his house had a 3-phase 600Amp service. He never could explain what he used it for.
Either the military had a hidden base below it, or he had 2 subbasements filled with grow lamps.:roll:

 

[suemarkp]

The OP said "out in the country not under local inspection". I took this to mean no codes apply. Do you see a hazard in using two paralleled 200A feeders that are using separate breakers instead of a listed ganged breaker?

Yes, this is crazy from a cost perspective. The only reason I could see to use a 400A panel would be if they wanted a whole house transfer switch. But I'd definitely encourage two separate 200A panels and putting anything that would ever be a generator desired load into just one of the panels.

 

[kwired]

The Power Company out in the county not under local inspection provides combo meter mains.
On the 400 Amp Combo.They come with (2) 200 Amp 1ph Feeder Breakers.(Not 1 400).

They are telling the customer that these can be used for 400 Amp Services and typically they are for
(2) Seperate 200 Amp MLO Panels)

But.

The Customers and electricians that dont know any better are thinking that they can install a Single 400 AMP Panel and take a feed from each 200a breaker in the Meter/Main to the single 400a Panel.

Hearing this floored me.
But off the top of my head I could see where someone could actually do this and never know it was wrong.

This opens the door for other issues.

Is the meter main to be considered the service disconnect? If so the lines to the house are feeders and not service conductors. 225.30 says "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". If you supply two feeders to two 200 amp panels you are in violation of this section. If you tie the two feeders together to make a single 400 amp feeder you are in violation at the source end with the parallel breakers.

This meter combo is good to supply two feeders to separate buildings but not what you need for supplying a single building with 400 amps when the meter combo is on a separate structure. It will work great to supply two 200 amp panels in the house if the meter combo is installed on the house.

 

[texie]

This opens the door for other issues.

Is the meter main to be considered the service disconnect? If so the lines to the house are feeders and not service conductors. 225.30 says "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". If you supply two feeders to two 200 amp panels you are in violation of this section. If you tie the two feeders together to make a single 400 amp feeder you are in violation at the source end with the parallel breakers.

This meter combo is good to supply two feeders to separate buildings but not what you need for supplying a single building with 400 amps when the meter combo is on a separate structure. It will work great to supply two 200 amp panels in the house if the meter combo is installed on the house.

If this combo meter/main is out in the yard or at the property line I would agree. I took the OP to mean it was mounted on the house, which would be compliant and done by the thousands.

 

[texie]

The OP said "out in the country not under local inspection". I took this to mean no codes apply. Do you see a hazard in using two paralleled 200A feeders that are using separate breakers instead of a listed ganged breaker?

Yes, this is crazy from a cost perspective. The only reason I could see to use a 400A panel would be if they wanted a whole house transfer switch. But I'd definitely encourage two separate 200A panels and putting anything that would ever be a generator desired load into just one of the panels.

I think in most states even if there is no inspection you still have to meet code for that state. Even if there is no code adopted you still have a duty to provide a safe installation. Two field paralleled breakers is not safe on many levels and this is a flaming NEC vilolation.

 

[kwired]

If this combo meter/main is out in the yard or at the property line I would agree. I took the OP to mean it was mounted on the house, which would be compliant and done by the thousands.

OK I reread the OP, I for some reason thought he said the meter/main was at a pole then a feed was run to the house. I either am losing it or maybe had some other post on my mind. It doesn't say anything about the location of the meter/main or the panel(s) being fed.

 

[Dennis Alwon]

My understanding is there is a 400 amp meter main panel with 2 different dp 200 breakers feeding one single 400 amp ML panel. I don't see how this is compliant as you are feeding one panel from two different breakers. This would not even be a parallel run.

 

[jap]

My understanding is there is a 400 amp meter main panel with 2 different dp 200 breakers feeding one single 400 amp ML panel. I don't see how this is compliant as you are feeding one panel from two different breakers. This would not even be a parallel run.

Your correct in your understanding Dennis.
This is a Radio Staion Transmission site not a house (although I dont know what difference it would make)
How could you ever even think about feeding a single 400 amp panel from 2 seperate 200 Amp Breakers although someone who didnt know any better could accidently install it that way.

If you turned off only one of the breakers you would still have power on the load side lugs coming from the other breaker.
If you only turned off one of the 200's you would still have power to the panel.
I'm not sure of what would happen if one of the feeders shorted out,,,,, would it trip both 200's? I'm not sure.
but both A phases and B Phases are common at the meter so the parralel feeders could be installed incorrectly.

I'm was looking for the code statement that clarified this a violation and I think it was mentioned above about the single fuse or breaker.

 

[jap]

and yes the combo Meter main is remote form the building.

it is not mounted on the building.

 

[Cavie]

The Power Company out in the county not under local inspection provides combo meter mains.
On the 400 Amp Combo.They come with (2) 200 Amp 1ph Feeder Breakers.(Not 1 400).

They are telling the customer that these can be used for 400 Amp Services and typically they are for
(2) Seperate 200 Amp MLO Panels)

But.

The Customers and electricians that dont know any better are thinking that they can install a Single 400 AMP Panel and take a feed from each 200a breaker in the Meter/Main to the single 400a Panel.

Hearing this floored me.
But off the top of my head I could see where someone could actually do this and never know it was wrong.

Anyone doing that has no business with tools in thier hands. Tell them to stop, drop the tools and back away.

 

[jap]

I already have but when I was on the phone I couldnt rattle off all of the violations that would come into play other than you cant do that because of this, and this, and this.


The DIY'er said the power company told him they used this setup for 400 Amp services all the time.

You can see where he would think that installing a 400 Amp Panelboard would be just fine.

It was the first time I had ever heard of anyone even thinking about installing it that way.

 

[texie]

and yes the combo Meter main is remote form the building.

it is not mounted on the building.

Since this is already installed and you have one, 400 panel fed by 2 sets of feeder conductors, why don't you just consider rebuilding the existing meter combo with a new self contained meter and 400 amp breaker or fusible switch. If the feeders are to short just put a 3R gutter in down low to slice them. Now that you you mention the remote setup, do you have a disconnect on the building already with a GES or is this another violation? Do you have an EGC to the building with the feeder? If someone did this type of thing, you have to wonder how many other violations there are.
The existing setup is an accident waiting to happen.

 

[Dennis Alwon]

and yes the combo Meter main is remote form the building.

it is not mounted on the building.

That would make no difference IMO. If one conductor from one of the breakers got cut or disconnected somehow the entire 400 amps would be on the 200 amp conductor and breaker. :happyno::jawdrop:

 

[jap]

Since this is already installed and you have one, 400 panel fed by 2 sets of feeder conductors, why don't you just consider rebuilding the existing meter combo with a new self contained meter and 400 amp breaker or fusible switch. If the feeders are to short just put a 3R gutter in down low to slice them. Now that you you mention the remote setup, do you have a disconnect on the building already with a GES or is this another violation? Do you have an EGC to the building with the feeder? If someone did this type of thing, you have to wonder how many other violations there are.
The existing setup is an accident waiting to happen.

He didnt ask me to rebuild it.
If he hadnt called I'd never had known about it.
I dont see where it being on the building or not, House or Commercial building makes any difference.
You still have 2 seperate feeds going to 1 common panelboard.

 

[texie]

He didnt ask me to rebuild it.
If he hadnt called I'd never had known about it.
I dont see where it being on the building or not, House or Commercial building makes any difference.
You still have 2 seperate feeds going to 1 common panelboard.

It only matters if the service is on the building if you were to correct the problem by replacing the single 400 amp panel with 2 200 amp panels because, as Kwire points out, it would violate 225.30. That is why I suggested my fix to change it to a single 400 amp breaker at the meter and it comes a legitimate parallel feeder. But since you are not being called on to fix the obviously wrong and dangerous original design, it's a moot point and case closed. The only thing I would do is issue a letter stating the concerns and hazard so there is a paper trail showing you did your best to make the owner aware and move on.