Aluminum SER

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dgrey

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Another contractor told me that the 2008 NEC effectively eliminated the use of aluminum SER within a dwelling unit to feed a sub panel or when used in a meter/main situation. (something about temperature rating?) I don't seem to find anything along these lines and was wondering if anyone had come to this same conclusion or heard of such a ruling.
 
infinity

infinity

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Well now you need to use much larger sized SER cable to feed subpanels, ovens etc due to the 60 degree restrictions in 334.80. Look at 338.10(B)(4)(a).
 
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dgrey

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So I take this to mean that I should use the 60 deg section of 310.16 to determine my SER size, which makes it either 300 mcm or 350mcm. Do they even make SER that size and is it readily available? This sort of stinks of the copper wire manufacturers getting something put into the code that benefits them but not nessecerally the installer or the final user. But I guess that would be the nature of business and the code is a business. So be it.
 
augie47

augie47

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from another thread:
"FYI, ALCAN is one manufacturer that makes it. It is currently being required in some areas of TN for 200 amp interior feeders and is locally stocked. That said, I undestand the requirement is debatable.
alcan.doc "
 
iwire

iwire

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dgrey said:
So I take this to mean that I should use the 60 deg section of 310.16 to determine my SER size, which makes it either 300 mcm or 350mcm. Do they even make SER that size and is it readily available? This sort of stinks of the copper wire manufacturers getting something put into the code that benefits them but not nessecerally the installer or the final user. But I guess that would be the nature of business and the code is a business. So be it.
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It has more to do with matching the rules for NM.

Essentially NM and SE are made the same and when they are used for the same purpose the rules should be the same.
 
infinity

infinity

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Copper or aluminum you still have to use the 60 degree ampacity. Under the 2005 and earlier code versions you could use the 75 degree ampacity.
 
electricmanscott

electricmanscott

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LarryFine said:
That's what he was saying. The options are use larger aluminum or (his point) switch to copper.
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But you still have to use larger copper too which is more expensive than AL so therefore you would use aluminum even though it is larger than you had to previously use it is less expensive than copper. WHEWW!


Obviously the code rule was brought about by the aluminum industry. :grin:
 
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dgrey

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I didn't think about it that way. I guess you would have to use the larger copper. Thats the way I roll lately, go off on a rant and then think it through. Sorry to the copper wire manufacturers out there. So the long and short of it is, whenever using SE/SER (copper or alum.) inside a dwelling it must be sized using the 60 degree column.(?)
 
PetrosA

PetrosA

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(rant/)
What bugs me is that this kind of costly change can get pushed through without any obvious kind of peer review. I want to see statistics. Let someone prove that SE cables installed to code were burning out between terminations, or the excess heat they gave off ignited surrounding materials, or that there really are a lot of places in homes that reach over 60? C on a regular basis (the hottest attic I've ever been in was 61? C and it was exceptionally hot due to inadequate ventilation) or even that the insulation broke down at a high enough rate to warrant the change. What's next, appliance circuits in #10, lighting in #12 and the demise of #14? I've never seen an SE cable indoors sized per the old methods damaged from anything other than a bad termination or something mechanical, but what do I know? I guess we just have too many natural resources laying around.

Here in PA we now have a so-called "Home Improvement Contractor" license that's a lot like this NEC change. It costs $35 per year and any contractor in any trade who does more than $5000 per year in residential renovation/service must buy it. All you need is a name and proof of insurance. The state Secretary General justified it by stating that in 2008 his office received 2100 phone calls from residents expressing some form of complaint about contractors. Out of 12.5 million residents, how statistically significant can 2100 phone calls be even if every single one was a valid complaint? Obviously significant enough to charge $35/yr. to every contractor in the state ;) Maybe these lawmakers took some ideas from the NEC...

(/rant)
 
George Stolz

George Stolz

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PetrosA said:
(rant/)
What bugs me is that this kind of costly change can get pushed through without any obvious kind of peer review.
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It was an openly made proposal, and the substantiation was just that simple. The manufacturer, the authority on cables, said that there was no difference in the insulation between NM and SER, and so they should abide by the same rules.

Let someone prove that SE cables installed to code were burning out between terminations, or the excess heat they gave off ignited surrounding materials, or ...
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I've seen bad terminations melt insulation of a #12 on a 20A. I have seen undamaged #14 on a 20A that had not been loaded heavily. Does that make it safe?

...that there really are a lot of places in homes that reach over 60? C on a regular basis (the hottest attic I've ever been in was 61? C and it was exceptionally hot due to inadequate ventilation) or even that the insulation broke down at a high enough rate to warrant the change.
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That's not the temperature rating of the conductor, that's the ambient temperature around the conductor. Look at the correction factors below 310.16. For a 60?C attic, you would need at least a 75?C-rated conductor and it would only be worth 58% of what it would be worth normally.

When you put 25A through a #14 NM or THHN conductor, the conductor is supposed to reach 90?C, and the insulation is supposed to withstand that. For NM, they have decided that we should not expose buildings to that temperature from that wiring method, and that the conductor should never exceed 60?.
 
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macmikeman

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electricmanscott said:
But you still have to use larger copper too which is more expensive than AL so therefore you would use aluminum even though it is larger than you had to previously use it is less expensive than copper. WHEWW!


Obviously the code rule was brought about by the aluminum industry. :grin:
Click to expand...

I think the code rule was brought about by the steroids and Tigers Milk industry, cause I have a hard time running 4/0 al ser with my little stick arms. The idea of trying to put a bend in 300 alum ser and get that thru a bored hole in a wood member by myself is unthinkable. Time to start visiting the jym while we are still on the 2005 around here.
 
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plate

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South East PA
Personally, I would still use the same SER cable as before, but reduce the feeder breaker size to 60A or 75A. Many times putting in a subpanel is a matter of additional (lightly loaded) circuits, not actual load.
 
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