Dwelling feeder

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mbrooke

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What is the code section that allows for an exception to an AC disconnect coming from a meter main without having to upsize the SER?
 

Dennis Alwon

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What is the code section that allows for an exception to an AC disconnect coming from a meter main without having to upsize the SER?


If I understand you correctly there is no exception. The ser must carry the entire load of the dwelling
 

augie47

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This was discussed at length thru a couple of Code cycles and I have to admit a bit of foggy memory, but I don't think there is one and therein lies a problem (or lays). Reduce the load by feeding the A/C at the service and the feeder no longer qualifies as a "whole house" feeder.
I know of no jurisdiction that requires it to be upsized, but I can't think of a Code section that directly allows such. Someone else might as it was thoroughly debated when the SE ampacity was reduced.
 

mbrooke

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This was discussed at length thru a couple of Code cycles and I have to admit a bit of foggy memory, but I don't think there is one and therein lies a problem (or lays). Reduce the load by feeding the A/C at the service and the feeder no longer qualifies as a "whole house" feeder.
I know of no jurisdiction that requires it to be upsized, but I can't think of a Code section that directly allows such. Someone else might as it was thoroughly debated when the SE ampacity was reduced.


Ok, so basically nothing strictly says either way. Kind of silly to upsize IMO.
 

resistance

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WA
I haven?t updated my code book from the 2008. But are you referring to T.310. 15(B)(6) vs. T. 310.16? T.310.15(B)(6) can be used if your install falls under 310.15B6?giving you an exception to using a larger conductor under table 310.16.
 

augie47

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Ok, so basically nothing strictly says either way. Kind of silly to upsize IMO.

Beauty is in then eye of the beholder. :)
What it "says" depends on who is reading (see below)

I haven?t updated my code book from the 2008. But are you referring to T.310. 15(B)(6) vs. T. 310.16? T.310.15(B)(6) can be used if your install falls under 310.15B6?giving you an exception to using a larger conductor under table 310.16.

As I mentioned earlier, I was a hotly debated subject when 338.10 changed the allowable ampacity of SE. So we were faced with one Section of the Code stating
SE has a 60? ampacity vs the allowances in 310.15(B)(6). That in itself
set up a controversy then add to that the fact that once you remove any load at the service, the feeder to the interior is not longer a "whole house" feeder and although its load is less it no longer qualifies for 310.15(B)(6).
Then the '11 Code changed the rules as to when the 60? rating applied.
You can perform some searches with the Forum and find multiple pages of argument as to how the situation must be addressed (hopefully this thread won't start the spitting contest all over) . Somewhat like preachers holding a Bible, each inspector can recite his own verse.
 

mbrooke

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United States
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Technician
Beauty is in then eye of the beholder. :)
What it "says" depends on who is reading (see below)



As I mentioned earlier, I was a hotly debated subject when 338.10 changed the allowable ampacity of SE. So we were faced with one Section of the Code stating
SE has a 60? ampacity vs the allowances in 310.15(B)(6). That in itself
set up a controversy then add to that the fact that once you remove any load at the service, the feeder to the interior is not longer a "whole house" feeder and although its load is less it no longer qualifies for 310.15(B)(6).
Then the '11 Code changed the rules as to when the 60? rating applied.
You can perform some searches with the Forum and find multiple pages of argument as to how the situation must be addressed (hopefully this thread won't start the spitting contest all over) . Somewhat like preachers holding a Bible, each inspector can recite his own verse.

Any links? Don't know how to name the subject. :ashamed1:

I have to agree, thus far Im having a hard time seeing anything explicit in the 11 and 14.
 
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