320 Meter Base Installation for a 400A Service

[wmeek]

I was wanting to make sure I was figuring this right. I have a 3 phase 320 Meter can with a 3" rigid riser with 3-500mcm and 1-350 mcm conductors. My total load calculation is 320A. By code i can go down to these 500 mcm conductors as long as toal load does not exceed 380A. Is this a correct install. Also has anyone installed parallel 2" for the primary side of meter can. I know meter can comes with a single hole for a hub, but was wanting to see if anyone has installed a myers hub for second conduit. Would this be legal per code.

Thanks

 

[tyha]

I dont see why you couldnt. weve done it comming from an underground service lateral. Why doesnt POCO install the line side. I think your best bet would be to install the 500 MCM on the line then drop to 2 - 2" with 3/0 on the load side for your SE

 

[krisinjersey]

Agreed

Agreed

We've always done the primary as a single set and paralleled the secondary to feed the two panels independently. I've never even thought of paralleling the primary. I want to see what everyone has to say on this as well.

 

[wmeek]

Our PoCo does not do the line side, the contractor is responsible for that in our area

 

[Dennis Alwon]

Unless poco has a rule I don't see why you can't parallel the primary. You need double lugs in the meter on the line side-- not sure I have seen that.

 

[wmeek]

I think I am going with the 3" riser with 3-500mcm, and 1-350mcm . I feel like it is easier to do it this way and then put the same on the load side of meter in to a gutter and tap off for each service disconnect ( 1-200A 3phase, 1-200A single phase) this is all 120/240V 3 phase service.

 

[augie47]

I'm not doing the work so it's easy to say, but, sight unseen. if I were going to to different panels, I would double lug the load side of the meter base and eliminate the tap, maybe the wireway, etc.

 

[wmeek]

Yes you are probally right to do it that way . but with a gutter You can take all grounding to a ground bar and then to your service disconnects

 

[wmeek]

With a service using 500mcm conductors (400A) So now if I set two service disconnects and parallel from meter base( 1-200A 3phase , 1-200A single phase) on this service i will install 4-3/0 and a #4 ground to 3 phase disconnect and 3-3/0 and #4 ground to single phase disconnects. Would the grounding of water pipe #1/0 , Gas pipe #1/0, And building steel #1/0 be correct as per 250.66. The ground rod would be a #6 conductor per 250.66 . Would this be a properly designed service per NEC

 

[stevebea]

I was wanting to make sure I was figuring this right. I have a 3 phase 320 Meter can with a 3" rigid riser with 3-500mcm and 1-350 mcm conductors. My total load calculation is 320A. By code i can go down to these 500 mcm conductors as long as toal load does not exceed 380A. Is this a correct install. Also has anyone installed parallel 2" for the primary side of meter can. I know meter can comes with a single hole for a hub, but was wanting to see if anyone has installed a myers hub for second conduit. Would this be legal per code.

Thanks

I find it hard to see how it would be advantageous to parallel the line side. On the load side however it seems to me it would be less work to double lug and parallel sets vs. gutter and taps. JMHO