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
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
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
"Properly" tightening an aluminum lug has got to be a cute trick.
A little too much "properly", and you have a stripped lug.
Lew
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
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
Or electric resistance heat, as one fellow pointed out.
Gentlemen, no Kiln's although I've lived close to the town that goes by that name. Resistance heat? this is Mississippi, I rarely use any heat. And I steadfastly refuse to put AC in, relying on natural ventilation, fans, and those lovely shade trees. When the summer sun finally does get an angle on the shop, in late afternoon, it is the signal to quit for the day. Don't want that dripping sweat to rust the machines or stain the wood. :~)
The 60 will do just fine.
Frank
I wouldn't use a 125 amp box with a line that feeds 60A - it's asking for trouble, and is probably not code. that said, you could get away with it is you were REAL sure of the power being used.
shelly
I'm confused.
What is the problem?
It's done every day and does not violate code.
lew
Asking for trouble in what way? Why would it not meet Code? There's no violation here -- I suppose you're concerned that the 125A panel could pull much more current than the feeder is rated for, but that can't happen if the feeder is properly installed with a 60A double-pole breaker at its source. If the feeder is simply taken off the main lugs, with no overcurrent protection at the source, then there certainly *is* both a Code violation and a serious hazard -- but the violation and hazard consist in having feeder conductors with no overcurrent protection, and are unrelated to the rating of the equipment at the other end of the feeder.
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