JDB3
Senior Member
- Location
- San Antonio, Texas
Having a discussion, what is the permissible capacity of 1/0 SER Al. feeding a sub-panel when passing through insulation in a residence? :?
1/0 SER Al.
- Thread starter JDB3
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jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
338.10(A)(4) Installation Methods for Branch Circuits and Feeders.
(a) Interior Installations. In addition to the provisions
of this article, Type SE service-entrance cable used for interior
wiring shall comply with the installation requirements
of Part II of Article 334, excluding 334.80.
Where installed in thermal insulation, the ampacity shall
be in accordance with the 60?C (140?F) conductor temperature
rating. The maximum conductor temperature rating
shall be permitted to be used for ampacity adjustment and
correction purposes, if the final derated ampacity does not
exceed that for a 60?C (140?F) rated conductor.
(a) Interior Installations. In addition to the provisions
of this article, Type SE service-entrance cable used for interior
wiring shall comply with the installation requirements
of Part II of Article 334, excluding 334.80.
Where installed in thermal insulation, the ampacity shall
be in accordance with the 60?C (140?F) conductor temperature
rating. The maximum conductor temperature rating
shall be permitted to be used for ampacity adjustment and
correction purposes, if the final derated ampacity does not
exceed that for a 60?C (140?F) rated conductor.
JDB3
Senior Member
- Location
- San Antonio, Texas
By the 2014 code, is there still something about if the wire is on a 100 amp or larger breaker/over current device and terminates on device listed for 75 or 90 degrees, then you may use the 75 degree column? :?
jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
I do not have a 2014, but I do not think that is correct. I have not heard that statement for the 2014.
jumper
Senior Member
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You may perhaps thinking of 110.14(C)(1), but that is not gonna be any help for this install.
jxofaltrds
Inspector Mike®
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- Mike P. Columbus Ohio
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- ESI, PI, RBO
Please note that this applies (in your example) even if you are using 310.15(B)(7)
JDB3
Senior Member
- Location
- San Antonio, Texas
:huh: Are you saying that 110.14 (c) (1) (b) (1) does not apply? Sorry,,I do not understand why it would not? :?
jxofaltrds
Inspector Mike®
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jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
I did not say it did not apply, I said it ain't gonna help.
All your terminations could be 90c, or even 150C for that matter, but your SER is in thermal insulation so your final ampacity cannot exceed the 60C value.
MasterTheNEC
CEO and President of Electrical Code Academy, Inc.
- Location
- McKinney, Texas
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Well now...that's a bit of a loaded question to answer now isn't it.
1) Are you using 310.15(B)(7) allowances (correctly)
2) Have you applied 338.10(B)(4)(a) properly...and if so will 310.15(A)(2) help your situation. In other words, how much thermal insulation are you speaking about.
While I was at the IAEI Western Section event their seemed to be quite a bit of confusion regarding Section 338.10(B)(4)(a) and being installed in insulation. I got with a few of the individuals and explained that while 338.10(B)(4)(a) exempts the demands of 334.80, the reason it does so is because 338.10(B)(4) has it's own thermal insulation requirements that must be followed. The one HUGE difference is that in 334.80, the allowance in 310.15(A)(2) does not apply....this is not the case in 338.10(B)(4)(a) as a whole. Which for those working with SE Cable can be HUGE.
Anyway...those are my opinions and i'm sticking with it (unless someone makes me change it..lol...:angel
jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
. The one HUGE difference is that in 334.80, the allowance in 310.15(A)(2) does not apply....this is not the case in 338.10(B)(4)(a) as a whole. Which for those working with SE Cable can be HUGE.
Anyway...those are my opinions and i'm sticking with it (unless someone makes me change it..lol...:angel
Only one problem, 310.15(A)(2) ain't gonna work for SER in thermal insulation. You only have one final ampacity. No portion is higher or lessor. The 60C does not just apply to the portion in the insulation.
JDB3
Senior Member
- Location
- San Antonio, Texas
Might be incorrect (but not wrong), but isn't the insulation for SE Type XHHW or THWN ? These types of insulation are not listed under the 60 degree column, but are in the 90 degree? So how would the 60 degree apply? :? :huh: The more I get into this, the more I am getting confused (long day / short night)
MasterTheNEC
CEO and President of Electrical Code Academy, Inc.
- Location
- McKinney, Texas
- Occupation
- CEO
lol...well you better explain that to the IAEI as well....lol
Here is a direct quote from an article in May-June 2013 by CMP 6 Member John Stacey (remember he sits on the panel that discusses this..lol)
"The most commonly used wiring type for services and feeders to individual dwelling units are SE cable (SER or SEU). For services, SE cable is allowed to be used at its listed rating of 75?C. For interior branch circuits and feeders, Section 338.10(B)(4)(a) limits SE cable run through insulation to be limited to its ampacity in the 60?C column of Table 310.15(B)(16). Note that Section 310.15(A)(2) Exception allows up to 10 feet or 10% (whichever is less) to run through insulation without limiting the SE cable to 60?C. This applies to other wiring methods as well; if less than 10 feet or 10% runs through an area of lower ampacity, it is acceptable to use the higher ampacity for the entire run."
Here is the entire article...Enjoy.
http://iaeimagazine.org/magazine/2013/05/16/whats-happening-to-table-310-15b7/
More....
"What if our feeder is SE cable running through insulation? Section 338.10(B)(4) allows us to start our calculation using the rating of the conductor to do any correction or adjustments; however, the final ampacity cannot exceed the values in the 60?C column. Now we have to pick a conductor that has at least 83 amperes in the 60?C column. A 3 AWG copper or 1 AWG aluminum conductor having 85 amperes in the 60?C column would satisfy the 83-ampere requirement for a 100-ampere feeder that runs through insulation (for more than 10 feet or 10% of the length of the run, whichever is less)."
Remember.....he is on CMP 6 mind you.....
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jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Well, just because I am wrong, that does not mean I gotta agree...
Aw, phooey................
Aw, phooey................
MasterTheNEC
CEO and President of Electrical Code Academy, Inc.
- Location
- McKinney, Texas
- Occupation
- CEO
Well, just because I am wrong, that does not mean I gotta agree...
Aw, phooey................
Oh I hear ya....dang opinions are like.....well you get the picture.:thumbsup:
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Well now...that's a bit of a loaded question to answer now isn't it.
1) Are you using 310.15(B)(7) allowances (correctly)
2) Have you applied 338.10(B)(4)(a) properly...and if so will 310.15(A)(2) help your situation. In other words, how much thermal insulation are you speaking about.
While I was at the IAEI Western Section event their seemed to be quite a bit of confusion regarding Section 338.10(B)(4)(a) and being installed in insulation. I got with a few of the individuals and explained that while 338.10(B)(4)(a) exempts the demands of 334.80, the reason it does so is because 338.10(B)(4) has it's own thermal insulation requirements that must be followed. The one HUGE difference is that in 334.80, the allowance in 310.15(A)(2) does not apply....this is not the case in 338.10(B)(4)(a) as a whole. Which for those working with SE Cable can be HUGE.
Anyway...those are my opinions and i'm sticking with it (unless someone makes me change it..lol...:angel
I brought that up in another thread and I wrote an email to Dave Mercier. He does not agree with you. I mention how art. 338 does not excluded the 310.15(A)(2) and he never responded.
Here is his response-- I think he is incorrect- may be the intent but it is not what the code states
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
Is Dave Mercier a CMP member or IAEI or just works at Southwire? Just curious.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
CMP and it was he who got the seu dropped to 60C. Apparently his company (southwire) did a study on the cables in firecaulking and said under full load the wire was breaking down. Now we all know that you never have seu under full load especially in a residence
jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
Well, if he is is a CMP member and agrees with me, then he's gotta be correct......:angel:
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
LOL... I also edited my post and added a bit of commentary
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