Help with 400 amp resi pedestal install

[jjhoward]

Cust has existing underground 200 amp service. He is looking to add about 100 amps of load in a shop by his attached garage. Load analysis for his existing home is 190 amps. (2 large A/C units, elect dryer, elect range, pool)

Presently the underground feed comes off a utility pole on his property about 110' from his house.
Was considering installing a 400 amp pedestal at the pole and bringing a second set of 200 amp conductors to the house. Install a second 200 amp panel and use this 2nd panel to feed his shop.

Question: Is it code complaint (2008) to only have the 2 200amp disconnects at the main breaker panels? These panels will be placed next to each other. No disconnect at the pedestal.

Thank you.

 

[augie47]

If POCO has no objection, install a 400 amp meter base on a pedestal, supply with adequate service condcutors and intercept the exsiting 200 amp u.g. to the house and add a 200 amp u.g. to the shop.

 

[jjhoward]

That was one way to do this, but going directly to the shop from the pole is a longer trenching job, and the portion of the driveway to be crossed is much wider; the area of the driveway in front of the 3-car garage.

Going to back to the side of the house where the existing meter pan and panel is a shorter distance and crosses a narrow part of the driveway.

Getting SER cable from the new panel to the shop is not that bad, mostly unfinished basement but for 1 10x12 room with a drop ceiling.

But a meter pedestal without a disconnect is OK?

 

[augie47]

Big OPPS ! on my part, I read "detached garage".
With an "attached" garage you need to group your service disconnects.
Per NEC you could group up to 6 service disconnects.

 

[Dennis Alwon]

Using 2- 200 amp disconnects from a 400 amp service is very common around here. Remember when you do this T. 310.15(B)(6) will not apply for your service conductors. This means with a load of 190 at the house 4/0 alumin. cannot be used, however if you move some of the load to the new panel and keep the load under 180 amps 4/0 would suffice.

 

[augie47]

Using 2- 200 amp disconnects from a 400 amp service is very common around here. Remember when you do this T. 310.15(B)(6) will not apply for your service conductors. This means with a load of 190 at the house 4/0 alumin. cannot be used,
.

Good catch, Dennis.
Boy, I really dropped the ball on this one

however if you move some of the load to the new panel and keep the load under 180 amps 4/0 would suffice.

In some jurisdctions, yes and in some, No.
Using SER, the 60? limitation might be enforced by the inspector.

 

[Dennis Alwon]

In some jurisdctions, yes and in some, No.
Using SER, the 60? limitation might be enforced by the inspector.

Ser is to the sub panels I was think about the service panels outdoors next to the meters. You are correct with se cable.

 

[iwire]

He is looking to add about 100 amps of load in a shop by his attached garage.

Can you clear up if the shop is attached or detached from the main building?

 

[wawireguy]

I haven't priced SER vs MC but you might want to consider using MC instead as you don't have to size it off the 60 degree column. Worth pricing out.

 

[Dennis Alwon]

What I don't get is why article 310.15(A)(2) exception doesn't come into play.

 

[jjhoward]

The garage is attached to the house. The shop is also in the house. The shop is the 3rd garage of his 3 car garage.

 

[Dennis Alwon]

If the panels are outside I would just install the meter at the house and come out twice to 2-200 amp panels.

 

[jjhoward]

Hi Dennis;
I am not planning to have a 400 amp disconnect at the meter pedestal.
What part of this install would disallow using T 310.15(B)(6) for sizing the service conductors?

 

[jjhoward]

The panels are in the basement.
Presently, the is a 200 amp meter pan with under ground feed; on the side of the house with a 200 amp main breaker panel in the basement back/back with the meter pan.

The plan is to place a 400 amp meter pedestal at the pole (100' away) and add another 200 amp underground feed to the house.

Replace the existing meter pan with a trough or splitter R3 enclosure, bring in 2 separate conduits into the trough/splitter enclosure.
Add a second main breaker panel in the basement next to the existing one.

 

[Dennis Alwon]

The panels are in the basement.
Presently, the is a 200 amp meter pan with under ground feed; on the side of the house with a 200 amp main breaker panel in the basement back/back with the meter pan.

The plan is to place a 400 amp meter pedestal at the pole (100' away) and add another 200 amp underground feed to the house.

Replace the existing meter pan with a trough or splitter R3 enclosure, bring in 2 separate conduits into the trough/splitter enclosure.
Add a second main breaker panel in the basement next to the existing one.

That would not be a legal install as you cannot feed a structure with 2 supplies.

225.30

 

[Dennis Alwon]

Hi Dennis;
I am not planning to have a 400 amp disconnect at the meter pedestal.
What part of this install would disallow using T 310.15(B)(6) for sizing the service conductors?

T 310.15(B)(6) is only allowed on conductors that feed the entire load of the structure.

 

[augie47]

That would not be a legal install as you cannot feed a structure with 2 supplies.

225.30

Dennis,
If he only puts the meter pan at the pole and brings in two sets of service conductors is it a violation ?
225 would only apply if there were disconencts at the meter.
There is one service..... at the pole.
How does this differ to having a 400 amp meter on the house feeding two adjacent panels ?

 

[jjhoward]

Would 230.40 exception 2 allow sets of service conductors to the separate panels?

 

[Dennis Alwon]

Would 230.40 exception 2 allow sets of service conductors to the separate panels?

I believe it may. Each underground run from the meter is a service entrance conductor and it is fed from one service lateral so it appears it would be compliant.

If disconnects were at the pedestal then I think you would have a violation.

 

[Dennis Alwon]

Dennis,
If he only puts the meter pan at the pole and brings in two sets of service conductors is it a violation ?
225 would only apply if there were disconencts at the meter.
There is one service..... at the pole.
How does this differ to having a 400 amp meter on the house feeding two adjacent panels ?

I wasn't thinking correctly-- I was thinking discos at the pedestal but that was clearly not the case. I must say that I have never seen it done this way.