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AJH has finale say..ill ask around to see how the other AJHs feel
The inspector is not usually the last say. Our authority having jurisdiction is the state engineer at the department of insurance. He can override an inspector and has done many times.

The trick is to not make the argument a confrontation. Say something I believe you are mistaken as that section pertains to residential however that is not the section that is applicable. Section 240.4(B) would be applicable.
 

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Do you know what that might be in the 2017 NEC?
Thanks if you do.

It is 310.15(B)(7). My guess is the inspector sees this which will allow 4/0 for 200 amps for a dwelling but in the op's case 240.4 will allow it also. The only difference is the load cannot exceed 180 amps in the commercial job.

I did a job where the engineer speced 250kcm. The shop was very small and his calculation had it at 103 amps, I believe I asked if I could use 4/0 aluminum and he said no at first and then I showed him 240.4(B) and he had never seen that and said to go ahead as they will never load that space up to 180 amps

(7) Single-Phase Dwelling Services and Feeders. For one family
dwellings and the individual dwelling units of two-family
and multifamily dwellings, service and feeder conductors
supplied by a single-phase, 120/240-volt system shall be permitted
to be sized in accordance with 310.15(B)(7)(1) through
(4).
For one-family dwellings and the individual dwelling units of
two-family and multifamily dwellings, single-phase feeder
conductors consisting of 2 ungrounded conductors and the
neutral conductor from a 208Y/120 volt system shall be permitted
to be sized in accordance with 310.15(B)(7)(1) through
(3).
(1) For a service rated 100 through 400 amperes, the service
conductors supplying the entire load associated with a
one-family dwelling, or the service conductors supplying
the entire load associated with an individual dwelling unit
in a two-family or multifamily dwelling, shall be permitted
to have an ampacity not less than 83 percent of the service
rating.
(2) For a feeder rated 100 through 400 amperes, the feeder
conductors supplying the entire load associated with a
one-family dwelling, or the feeder conductors supplying
the entire load associated with an individual dwelling unit
in a two-family or multifamily dwelling, shall be permitted
to have an ampacity not less than 83 percent of the feeder
rating.
(3) In no case shall a feeder for an individual dwelling unit
be required to have an ampacity greater than that specified
in 310.15(B)(7)(1) or (2).
(4) Grounded conductors shall be permitted to be sized
smaller than the ungrounded conductors, if the requirements
of 220.61 and 230.42 for service conductors or the
requirements of 215.2 and 220.61 for feeder conductors
are met.
 

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Discussion Starter · #23 ·
It is 310.15(B)(7). My guess is the inspector sees this which will allow 4/0 for 200 amps for a dwelling but in the op's case 240.4 will allow it also. The only difference is the load cannot exceed 180 amps in the commercial job.

I did a job where the engineer speced 250kcm. The shop was very small and his calculation had it at 103 amps, I believe I asked if I could use 4/0 aluminum and he said no at first and then I showed him 240.4(B) and he had never seen that and said to go ahead as they will never load that space up to 180 amps
Where does it state it cant go above 180 amps
 

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Where does it state it cant go above 180 amps
The ampacity of 4/0 doesn't change so the load can only be what T 310.15(B)(7) states and that is 180 amps. 240.4(B) allows a 200 amp breaker but the load cannot be more than the ampacity of the wire.
 
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Discussion Starter · #25 ·
The ampacity of 4/0 doesn't change so the load can only be what T 310.15(B)(7) states and that is 180 amps. 240.4(B) allows a 200 amp breaker but the load cannot be more than the ampacity of the wire.
I see ...ok got it...thanks a bunch for all the imfo this weekend...also do they make a URD that is MULTI use...like USE and USE-2
 

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I see ...ok got it...thanks a bunch for all the imfo this weekend...also do they make a URD that is MULTI use...like USE and USE-2

That is all I can buy at my supplier. True URD is not compliant or listed in the nec. Check where you got it, my bet is it is use-2
 
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The ampacity of 4/0 doesn't change so the load can only be what T 310.15(B)(7) states and that is 180 amps. 240.4(B) allows a 200 amp breaker but the load cannot be more than the ampacity of the wire.
Okay, can you help me please.

When you type "T 310.15(B)(7)" I assume you are meaning a Table 310.15(B)(7) and not section 310.15(B)(7) (which is all verbal and does not state " T 310.15(B)(7) states and that is 180 amps".

My 2017 edition goes from T 310.15(B)(3)(a) on page 149 to no Tables on page 349 to T 31015(B)(16) on page 350. I do not see a T 310.15(B)(7). If someone will please either tell me where I'm thinking wrong or show me where this Table is?

Thanks.
 
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My bad, I should have looked... they changed the table number--- T 310.15(B)(16) is for ampacities but I thought you were asking about what the inspector was thinking about. My guess was he misunderstood section 310.15(B)(7). Does that help
 

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If it is USE-2 then it should also be marked Rhw, Rhw-2, Use-2 and Rhh, Rhw and the others are allowed inside a building. Use cannot be but Use-2 can be used inside, The following is from here but I am sure there are other sources
Well Well it happened again I talked to the inspector and he says that he will not allow USE-2 indoors I sent over the information I got from you about a year ago from South West wire when it failed. So I'm not sure how I can do this because I don't think that the code book shows that you can use USE- 2 Maybe I could have somebody from Southwest wire write me a letter stating that USE-2 is suitable for indoor and is a dual rated insulation... I like using the USE going from meter enclosure to panels .It's easier to work with since it's wound together...I'd like to win this...morg
 

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Well Well it happened again I talked to the inspector and he says that he will not allow USE-2 indoors I sent over the information I got from you about a year ago from South West wire when it failed. So I'm not sure how I can do this because I don't think that the code book shows that you can use USE- 2 Maybe I could have somebody from Southwest wire write me a letter stating that USE-2 is suitable for indoor and is a dual rated insulation... I like using the USE going from meter enclosure to panels .It's easier to work with since it's wound together...I'd like to win this...morg
Time to go over his head.
 

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That is not USE cable. USE cable has an overall outer jacket. It cannot be used indoors because that jacket is not flame-retardant.

What you have in your picture is just three USE-2 conductors twisted together. The 2020 NEC defines it as a “service conductor assembly” in 338.2. Please refer to the pics.
 

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I could I quess..just curious about the use-2 and its suitable for indoor use...morg

The old USE was not allowed to enter the house because they never did a vertical flame rating, however, USE-2 is either RHW or a blend of Xhhw and thwn or something along those lines. So why wouldn't he allow RHW in the house if it is installed in conduit. The guy is just wrong, IMO
 
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The old USE was not allowed to enter the house because they never did a vertical flame rating, however, USE-2 is either RHW or a blend of Xhhw and thwn or something along those lines. So why wouldn't he allow RHW in the house if it is installed in conduit. The guy is just wrong, IMO
we have been talking via emails he just plainly said that USE- 2 is not allowed inside I guess the information from the wire manufacturers was not enough to convince him...MORG
 

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we have been talking via emails he just plainly said that USE- 2 is not allowed inside I guess the information from the wire manufacturers was not enough to convince him...MORG
I had an inspector like this once in a small town. The manufactures info was enough to convince the state construction board to convince him. The “hadn’t got around to writing it in the code” so I didn’t get around to following it.
 
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