Wire size for 250' distance to garage?

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Frank Boettcher wrote:

BTW, forgot to ask.
Any chance you have access to the termination equipment for aluminum conductors (rent, barter, whatever)?
If so, #4 AWG aluminum should be very attractive.
Lew
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I have 30 years experience operating a small electrical contracting business. In that time, I've only observed a very few circuit breaker panels and breakers that are not designed for direct connection to aliminum conductors.
What kind of termination equipment, other than anti-oxidation paste, do you refer?
Gary Kasten Kasten Electric St. Peters, MO
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9.9 Fingers wrote:
> > I have 30 years experience operating a small electrical contracting > business. In that time, I've only observed a very few circuit breaker > panels and breakers that are not designed for direct connection to aliminum > conductors. > > What kind of termination equipment, other than anti-oxidation paste, do you > refer?
I'm dating myself, but way back when aluminum conductors first started appearing, it required a crimp connector to trap the sheep dip(Al-Nox, etc).
Appears thing have changed in Kansas City, as the old song goes.
How does a direct connect to a c'bkr lug trap the sheep dip and prevent oxidation?
Lew
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Lew,
The lugs, (part of the breaker where the wire is connected) are *made of aluminum*. Since there's no dissimilar metal problem to fight, coating the end of the aluminum with "mother-in-law juice", and then *properly* tightening down the screw on the breaker does a fine job of keeping the connection clear of oxidation.
The parts of the conductor that aren't trapped under the breaker screw or trapped against the back and sides of the lug aren't actually transferring current. Apparently, enough of the anti-ox is trapped and coats the wire and the lug at the points where contact is made to prevent problems.
Frequently, we remove metersockets and circuit panels that have been connected to aluminum since the mid 1960's; and as long as the connections were installed properly, the amount of failed connections are very few. This is in Missouri, where we have 4 seasons, at least one without much humidity. Can't say if this would hold true for the more humid parts of the US.
Gary Kasten Kasten Electric St. Peters, MO
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9.9 Fingers wrote:
> The lugs, (part of the breaker where the wire is connected) are *made of > aluminum*. Since there's no dissimilar metal problem to fight, coating the > end of the aluminum with "mother-in-law juice", and then *properly* > tightening down the screw on the breaker does a fine job of keeping the > connection clear of oxidation.
"Properly" tightening an aluminum lug has got to be a cute trick.
A little too much "properly", and you have a stripped lug.
Lew
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Yeah... Practice and PATIENCE are required. A good slug of anti-ox on the conductors and a little bit of electrical silicone on the lug's threads and snug it down. Wait 4,5,6 minutes while you pick up your tools, check other connections, BS with the customer,,,, whatever.
Snug it again.... Wait some more. Check it again. Usually the third time will give you very little (or no) rotation. After that... LEAVE IT ALONE!!!
Obviously, a 200 amp 4/0 aluminum connector takes more effort than a #2 aluminum. But the "third times the charm" technique works for most of the "common" sizes. Judging just how much rotational force takes either a LOT of practice or a torque wrench... (BOTH are good to have!) ;-)
GWK
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9.9 Fingers wrote:
> > Yeah... Practice and PATIENCE are required. A good slug of anti-ox on the > conductors and a little bit of electrical silicone on the lug's threads and > snug it down. Wait 4,5,6 minutes while you pick up your tools, check other > connections, BS with the customer,,,, whatever. > > Snug it again.... Wait some more. Check it again. Usually the third time > will give you very little (or no) rotation. After that... LEAVE IT ALONE!!! > > Obviously, a 200 amp 4/0 aluminum connector takes more effort than a #2 > aluminum. But the "third times the charm" technique works for most of the > "common" sizes. Judging just how much rotational force takes either a LOT > of practice or a torque wrench... (BOTH are good to have!) ;-)
The classic description of how to overcome the cold flow problem with aluminum conductors.
Now if you want to have some fun, do some work with low voltage marine DC wiring complete with terminals, sheep dip, shrink tubing and special crimp tools.
Lew
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On Wed, 18 Jul 2007 18:11:33 GMT, snipped-for-privacy@milmac.com (Doug Miller) wrote:

I'm confused here. All that I've found is rated at 55 amps. It seems that regardless of the insulation rating on the individual conducters in the cable that might take it to 75 or 90C, the rating reverts back to 60C which is 55 amps for any #6 "romex" cable. Not sure what the logic is there or even if I understand it fully.

Not much chance, I think. Breezeway is flat roof or actually a one way minor slope with roof sheathing on top and ceiling sheathing below the rafters. There is a 12/2 wg in there that was the original light cable for the carport, however, It would be too much to expect to have those holes though the rafters be large enough for the larger cable. Got a right angle turn in there also.

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Since there isn't any such thing as a 55A breaker, Code permits the conductors to be breakered at 60A. [2005 NEC, Articles 240.4 and 240.6, paraphrased]
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Regards,
Doug Miller (alphageek at milmac dot com)
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On Wed, 18 Jul 2007 22:47:13 GMT, snipped-for-privacy@milmac.com (Doug Miller) wrote:

Thanks. I didn't know that. That is the way I will go. Least cost and, since I am the labor, least amount of that in the attic.
Frank
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You're welcome. General rule, any time there isn't a standard breaker corresponding to the rated ampacity of the wire or cable you're using, you're permitted to go up to the next standard breaker. The entire NEC is online here at the URL below; consult Article 240.4(B) if you want all the gory details. Article 240.6(A) lists the standard ratings. http://nfpa-acs-01.gvpi.net:8080/rrserver/browser?title=/NFPASTD/7005SB
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Regards,
Doug Miller (alphageek at milmac dot com)
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