310.15(B)(6) vs IRC E3603.1

[Span]

IMO 200A panel can not sub to another 200A sub-panel.

1. No slot at main able to accomandate another 200A breaker, lower A maybe.

2. 2/0 feeder bending radius.

If they realley need 200A to house, use meter socket instead of meter panel at garage then 2/0 to main panel at house, and have another feeder or sub to garage. Will this way aceptable?

 

[Dennis]

IMO 200A panel can not sub to another 200A sub-panel. 1. No slot at main able to accomandate another 200A breaker, lower A maybe.

2. 2/0 feeder bending radius.

If they realley need 200A to house, use meter socket instead of meter panel at garage then 2/0 to main panel at house, and have another feeder or sub to garage. Will this way aceptable?

That is not correct. There are feed thru lugs on some 200 amp panels. In this setup you do not add a 200 amp breaker but instead you are using the main breaker as the lugs are attached to the buss.

You are correct in that many panels will not allow more than 110 amps or so across any stab. This is not the case with all panels especially the meter main panels.

 

[gfretwell]

I have a QO 150a in my garage panel that grabs 8 slots. I think they also make that in 200

 

[jar546]

There are several replies up thread that imply the feeder beyond that disconnect with another load attached must be 310.16, not 310.15(B)(6).

Is that your opinion too?

What is the general consensus?

 

[gfretwell]

If you can (and do) use 310.15(B)(6) for the service, you should never need bigger wire anywhere on that service. That is how I read the first paragraph.

 

[Dennis]

If you can (and do) use 310.15(B)(6) for the service, you should never need bigger wire anywhere on that service. That is how I read the first paragraph.

It seems like we are still caught up on the bigger wire rather than a higher ampacity. Either no one understands what I have been saying or you all think I am nuts.

Okay

You run 3/0 copper to a panel next to the meter. Short nipple from meter to service panel. 3/0 @75C is rated 200 amps. Not a problem. Now I run 3/0 copper ser cable from the main panel to the sub panel 50 feet away. I go thru a crawl space and up thru the bottom plates. Now SER is rated 75C if it is not run in insulation and there is no caulk in the hole where you come up from the crawl area. Since we must caulk that hole the SER is now rated 60C. 3/0 SER cable at 60C is rated 165 amps. Now it is no longer and good for 200 amps so we must use 4/0 as long as the load is not greater than 195 amps.

So when you say it never has to be bigger that is not always the case. This is why I pipe all my 200 amp panels if possible.

 

[jwelectric]

We are allowed diversity when doing a service calculation that we are not allowed when doing a remote panel calculation.

In a dwelling the service will never see the total calculated load but it is possible to have a remote panel loaded to the full amount of the rating.

When the NEC addresses the feeder as outlined in this thread then the remote panel could have a full load even in the scenario outlined in the original post therefore the feeder conductor must be sized to the calculated load.

In the case of the feeder of the dwelling unit all one has to do is protect the feeders by 240.4(B)

See 215.3

Once we leave the service overcurrent device then the feeders must comply with 240.4(B) as far as the overcurrent protection

 

[peach]

we are still under 2005 (having recently crawled from 1996), and will only be going as far as 2011 any time soon (probably next year).

Since the POCO can deliver 200 amp using #2 if they chose to (and we can't tell THEM that they are wrong - perish the thought), I'm guessing the meter must transform power somehow. Look up at a service entrance from the transformer once.

I will boot this over to my senior electical inspector (hub/selectric from the old BB) for his consideration.