Sub Panel Feed

[csoc64]

This is an off the cuff question, as I don't have my code book with me. If I have a 125 amp bus sub panel fed from a 100A breaker in a 200A main panel, can I feed up to 50A into the sub panel, or am I still limited to 40A based on the main panel ratings (200A breaker / 200A bus). 2014 Code applies.

 

[Dennis Alwon]

I don't understand your question. You can feed as many sub panels as you want at any amperage as long as the calculated load is not more than any of the panels , feeders or mains.

 

[SolarPro]

Assuming your question relates to interconnecting parallel power production sources, here's the relevant language from the NEC 2014:

http://forums.mikeholt.com/showthread.php?t=158930&page=3&p=1540635#post1540635

Note that the backfed breaker rating is no longer used for ampacity calculations, but rather 125% of the inverter(s) output circuit current. That will allow additional interconnected capacity.

 

[Dennis Alwon]

I missed that the forum was on photovoltaic- sorry

 

[jaggedben]

This is an off the cuff question, as I don't have my code book with me. If I have a 125 amp bus sub panel fed from a 100A breaker in a 200A main panel, can I feed up to 50A into the sub panel, or am I still limited to 40A based on the main panel ratings (200A breaker / 200A bus). 2014 Code applies.

The short answer is that you are still limited to 40A breaker, unless you can meet the new 705.12(D)(3)(c)

 

[Zee]

This is an off the cuff question, as I don't have my code book with me. If I have a 125 amp bus sub panel fed from a 100A breaker in a 200A main panel, can I feed up to 50A into the sub panel, or am I still limited to 40A based on the main panel ratings (200A breaker / 200A bus). 2014 Code applies.

No. You cannot exceed 40 A PV.
(of course, the usual option of downsizing the 200A main breaker to 175A would allow an extra 25A PV to play with====>65A PV total - instead of 40A.)