600 KCM THHN

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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
how much is red tank a gallon there?

i bought #2 diesel here today at $3.99, and that is the lowest for 25 miles.
a 100 hp diesel engine uses fuel at a pretty good clip.

Diesel fuel 0.048 gal/hr per horsepower.

at $3.50 a gallon, it's $16.80 an hour.
figuring $3.00 for fuel, and .50 per hour
for maintenance and fueling.

That includes motor fuel taxes that are not required to be paid if you are using it for irrigation purposes. My guess is that even so the net cost of using electricity versus diesel these days makes it cost effective to run power a long way.

personally, I do not understand why people are not going with more medium voltage stuff for these longer runs. it would seem to be more cost effective, even if you have to install a transformer at the end.
 
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iwire

Moderator
Staff member
Location
Massachusetts
it also gets weird above 500 MCM....
what usually drives it is copper weight, but infrequently used
sizes cost more, and above 500 is infrequently used.


Likely an area thing, we install a lot of 600 copper THHN and XHHW.



i'm not fond of aluminum wire, unless the terminations are
hypressed. set screw lugs loosen up, unless retorqued
periodically,

You really can't 're-torque' you would have to remove, cut, strip and reinstall.

I see very few AL failures in real life.
 

kwired

Electron manager
Location
NE Nebraska
That includes motor fuel taxes that are not required to be paid if you are using it for irrigation purposes. My guess is that even so the net cost of using electricity versus diesel these days makes it cost effective to run power a long way.

personally, I do not understand why people are not going with more medium voltage stuff for these longer runs. it would seem to be more cost effective, even if you have to install a transformer at the end.

When he used the term "red tank" he was talking about dyed fuel that does not have road taxes on it.

I am sure that fuel cost is one reason so many are switching to electric wells. Maintenance of electric system is also much less.

Medium voltage makes sense, who is going to maintain it? If it is customer owned, POCO maintenance is not happening. It is bad enough that farmers play with the under 600 volt stuff and really make a mess of things, do we really want them to have acess to medium voltage equipment?

If these lines are POCO owned you realize how much more miles of line there is that they will be maintaining in area like where I am where you can't drive more than a mile or two without there being at least one irrigation system and in many cases every quarter section of land has one on it.

They made a positive step toward safety just by eliminating corner grounded delta systems. There used to be quite a few of them around here, now you will not find any. Nothing wrong with a corner ground delta, until the farmer starts doing his own installations and repairs.
 

ed downey

Senior Member
Location
Missouri
Fulthrotl, Have you seen any issues with the AA-8000 Series Aluminum conductors?
I have used these conductors in Hospitals, Data Centers and various other buildings for the last 18 years and have not heard of an issue with the conductor. We originally used compression lugs and the Bi-Pin compression connectors but I have not used that type of termination on most of the projects for the last 10 years.

As i-wire has said I have not seen any issues with the Aluminum Alloy conductors and would like to hear any true (first hand) stories about issues with the AA-8000 series conductors.
 

cdslotz

Senior Member
Yep


701ecmALUMpic1.jpg
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
They made a positive step toward safety just by eliminating corner grounded delta systems. There used to be quite a few of them around here, now you will not find any. Nothing wrong with a corner ground delta, until the farmer starts doing his own installations and repairs.

why would it be less safe to work on a corner grounded system?
 

Fulthrotl

~Autocorrect is My Worst Enema.~
why would it be less safe to work on a corner grounded system?

there's an informational note in 2011 nec about
the grounded conductor in a 3 phase delta not
being derated in size.... so i'm guessing there
have been problems with that in the field.... literally.

250.26 Conductor to Be Grounded — Alternating- Current Systems.
For ac premises wiring systems, the conductor to be grounded shall
be as specified in the following:
(1) Single-phase, 2-wire — one conductor
(2) Single-phase, 3-wire — the neutral conductor
(3) Multiphase systems having one wire common to all
phases — the common conductor
(4) Multiphase systems where one phase is grounded —
one phase conductor

(5) Multiphase systems in which one phase is used as in
(2) — the neutral conductor

i'm guessing that when creative farming gets into doing
stuff with this, the creative farmer uses a smaller conductor
for the grounded phase.... "cause it's just a ground... " :p
 

Fulthrotl

~Autocorrect is My Worst Enema.~
Fulthrotl, Have you seen any issues with the AA-8000 Series Aluminum conductors?
I have used these conductors in Hospitals, Data Centers and various other buildings for the last 18 years and have not heard of an issue with the conductor. We originally used compression lugs and the Bi-Pin compression connectors but I have not used that type of termination on most of the projects for the last 10 years.

As i-wire has said I have not seen any issues with the Aluminum Alloy conductors and would like to hear any true (first hand) stories about issues with the AA-8000 series conductors.

not i, said the little red hen... but i've not installed aluminum feeders.
i have checked setscrews on aluminum feeders in dry type transformers,
and found the setscrews loose, and the lugs quite hot... over 100 degrees
over the winding temperature.

but they were working....

there is obviously a lot of prejudice against aluminum wiring, and i freely
admit to having some myself, but i'm ok with aluminum wiring provided
it's done with hypress lugs instead setscrew lugs... but that's me, not the NEC.

setscrew lugs, if listed as approved for AL connections, are approved.
 

kwired

Electron manager
Location
NE Nebraska
why would it be less safe to work on a corner grounded system?

For qualified people that understand it, and use safe work practices - not really a lot of difference. For the farmer that doesn't know a lot, but is willing to keep trying something else until it works - big difference. 480 volts to ground is not very forgiving if you get in the way, 277 is bad enough. With a 277/480 system you have a 4th conductor that they do understand somewhat better is a grounded conductor with a three wire corner grounded system they don't quite get it, and will not isolate grounded from grounding beyond the service equipment.

One time we had a guy that had underground problems call us out to check it out. It was 480 volt corner ground system. Was common practice for POCO to install a 3 pole fused disconnect on the service pole and put a slug in place of the fuse in the grounded phase. This guy kept blowing one of the fuses, so he thought a solution may be to switch the slug into the fuseholder that kept blowing fuse. He said there was a fire at top of pole (transformers were there) and he shut it off and put the fuses back in right places before calling POCO. Is that enough to convince a person that unqualified not only shouldn't play with electricity, but especially something not quite so common to non electricians like a corner grounded delta.
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
UL does not allow its use in a UL508a panel though.

UL508a is a listed industrial control panel. I don't know why they don't allow AL conductors.



Field wiring can be either Cu or AL though.

Most everybody now is putting a disconnect outside the panels to get around the 70E requirement of PPE due to voltage still in the enclosure even though the internal disconnect is off. So it would be feasible to run aluminum to the external disconnect, then change over to copper into the panel.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Most everybody now is putting a disconnect outside the panels to get around the 70E requirement of PPE due to voltage still in the enclosure even though the internal disconnect is off. So it would be feasible to run aluminum to the external disconnect, then change over to copper into the panel.

UL does not prohibit landing AL conductors on field terminals inside of UL listed control panels. They only prohibit the use of AL conductors that are wholely contained within the control panel.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Most everybody now is putting a disconnect outside the panels to get around the 70E requirement of PPE due to voltage still in the enclosure even though the internal disconnect is off. So it would be feasible to run aluminum to the external disconnect, then change over to copper into the panel.

I have often wondered if one could not just make some kind of shroud to put around the incoming terminals that would prevent contact with the live wires there to deal with this problem.

Most panel mounted MCCBs either come with or offer such an option.
 

twoelk

Member
Location
USA, West Coast
I about fell out of my chair when I got the price back on some 600 THHN. Almost $12 a foot - the stuff is like gold these days. I know it is mostly set by the price of copper, and is pretty much fixed to that, but do any of you guys know any place that is consistently less expensive? maybe some online seller? Even 5% on a larger order is a good chunk of change.

Even 350 was almost $7 a foot.

I can see why AL wire has become so popular.

I think you should shop around.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
any suggestions as to where? our purchasing guy is pretty good at finding wire at better prices than what our local electrical distributors are willing to sell it at.

copper is nuts right now. my wholesale house gets quotes from their suppliers
that are good till end of business that day. not even 24 hours.

quotes i made 3 months ago, the wire has gone up 60%.
my quotes that are heavy on wire have a two week shelf life.
they want to go after that, i look at the wire prices and adjust the quote to reflect
the change in copper price.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
Most everybody now is putting a disconnect outside the panels to get around the 70E requirement of PPE due to voltage still in the enclosure even though the internal disconnect is off. So it would be feasible to run aluminum to the external disconnect, then change over to copper into the panel.

i understand the logic, but if you are killing the feeder, why not just lock it out at the OCPD supplying the feeder?
in an industrial application, i can see where the convenience of having the disconnect right at hand might very
well be worth the price of the switch.
 
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