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Service Drop Cable

Discussion in 'Electrical Engineering' started by Kissi Asiedu, Sep 12, 2005.

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  1. Guest


    Service drop is the utility overhead conductor. A service lateral
    would be the utility side of an underground service.
    They are also referred to service conductors.
    Service ENTRANCE conductors are the customerr side of the "service
    point" which is usually at the service head but it may be in the meter
    base with an underground service.
     
  2. Chris

    Chris Guest

    So when an old timer comes in and says he wants "knot knot" (or however it
    is spelled), you know were to send him? :)
    I am pretty sure on this side of the coast it is grey at HD. Might just be
    a sourcing thing, as they are heavy and they might have local sources for
    it.

    I know what you mean. Some customers tie up the damn clerks for a 1/2 hour
    asking them to design the whole circuit for them. All the while I am
    sitting there waiting to get some wire off the rack. Another reason I do
    not bother there.
     
  3. PCK

    PCK Guest

    pretty hard on the guy he has the right answers for the wrong reasons dont
    ya think
    better advice than alot in this newsgroup
     
  4. Chris

    Chris Guest

    True, and no offense to the guy. Just a lot of bad experiences with HD and
    anything electrical.

    I can at least give him an A for effort.
     
  5. John Gilmer

    John Gilmer Guest

    wire.

    Gad!

    Why not? (I understand not selling, say, #6 and small Al wire. But why no
    the BIG stuff?
     

  6. I don't really know the exact reasons. However I thought that Aluminum
    wire was not legal in the US.

    It would be nice if we had the large ones in Al, those spools of copper
    #2 weigh like 500 pounds!

    I suspect one other reason might be that it would be easy for the
    customers to become confused by the different types of wire, and choose
    the wrong one.
     
  7. Guest


    The only aluminum wire that is not legal for branch circuits and
    feeders in the US is the old 1350 alloy. The new AA8000 alloys are
    perfectly legal, and safe although the bad reputation still exists.
     

  8. Hmm, didn't know that. Ok, so is this 1350 alloy just a different
    formulation of aluminum for the wire? The AA8000 being the newer
    formulation and the 1350 being the fomulation used in the 50s, 60s or
    70s or whatever?

    For this new stuff, the AA8000, would you use the same gauge as you
    would with copper in any situation? Or would you use one gauge thicker
    than you would with copper?


    I know what a branch circuit is, but what is a feeder?
     
  9. Guest


    You still have to follow the aluminum ampacity table, which is
    generally one size larger but once you get to 70a (4ga copper) the
    aluminum slips another size.

    The old alloy was originally designed for overhead spans and breaks
    pretty easily if it is bent sharply. The newer alloy is designed to be
    harder to break from bending and the expansion characteristic is more
    in tune with the screws used in Cu/Al terminals. Used with CO/ALr
    devices it would probably be OK but nobody will actually try it. In
    larger sizes, using set screw terminals it has really never had
    problems. Since most lugs these days are an aluminum alloy it actually
    has a better expansion characteristic.

    Old legends die hard tho.
     
  10. Bud--

    Bud-- Guest

    For 15 and 20A branch circuits, the current alloy aluminum expansion
    characteristics may have been substanitally fixed. But it has the same
    oxidization problem as the old aluminum wire. On small branch this would
    produce the same safety problems in wire nuts, if nowhere else.

    Bud--
     
  11. Guest

    I suppose that is why they invented anyi-oxidants huh?
    Have you seen the Ideal 65 wirenut?
     
  12. Bud--

    Bud-- Guest

    A lot of information on aluminum wiring has been collected at
    http://www.inspect-ny.com/aluminum.htm
    which also includes web links. Information below is derived from this
    site. The best of the links is
    http://www.inspect-ny.com/aluminum/alreduce.htm
    which is based on information derived from extensive tests at the
    Wright-Malta Corp.


    IDEAL #65 TWISTER
    The Consumer Product Safety Commission (CPSC), reacting to fires caused
    by aluminum wiring connections, contracted with Wright-Malta Corp., an
    independent test laboratory, to do extensive testing. Some of this
    testing was done on the Ideal #65 Twister wire-nut. This wire nut
    appears to be a standard Ideal wire nut with antioxide paste inside. The
    testing found that the Ideal #65 was not better than other wire-nuts
    that were not listed for aluminum wire. (Information at
    http://www.inspect-ny.com/aluminum/alreduce.htm
    topic "D"). In addition to failing, the Ideal plastic shell and included
    antioxide paste burned. (There is a multipage slide show of a
    presentation to the CPSC from the Wright-Malta lab at:
    http://www.inspect-ny.com/aluminum/piclib02.htm
    This includes pictures of the Ideal #65 burning.) As a result of the
    laboratory tests, the CPSC requested that UL change its test procedures
    to be more realistic. Ideal told the CPSC that "the Ideal #65 was not
    intended for use for [pigtailing retrofit], but only for such
    applications as connecting lighting fixtures and ceiling fans. Ideal
    committed to CPSC to change its advertising and instructional
    information accordingly, but did not follow through on that commitment."

    WIRE-NUTS ON ALUMINUM WIRE
    The Wright-Malta Corp. tests found that because of surface oxide, there
    is poor initial wire-to-wire contact to aluminum wire(s). The steel
    spring in the wire-nut cuts through the oxide and makes contact, so
    initally about 60% of the current flows through the spring. Over time
    and use, the contact between the wires may be reduced, sometimes to
    zero. The contact from aluminum to spring may also be reduced so only a
    small part of the spring is carrying the current. However steel is not a
    good conductor. Tests found a 2 volt drop across the wire nut through
    the spring at 17 amps. This is only about 0.1 ohm resistance, but it is
    a 34 watt heater. At this current level the spring is red hot. In other
    tests, the spring is red hot at 12 amps. This destroys the insulation on
    the wires and the wire nut and can start a fire.

    THE NEW ALUMINUM ALLOY WIRE HAS THE SAME OXIDE PROBLEM AS THE OLD WIRE.

    The only fix recommended by the CPSC is the COPALUM compression sleeve
    that makes a cold weld to the wires.

    Note that
    http://www.inspect-ny.com/aluminum/alreduce.htm
    topic "C" and "A", gives a detailed procedure for using wire-nuts with
    aluminum wire. A critical part is applying antioxide paste to the
    stripped wire then abrading the wire to remove the oxide. Know anyone
    who does that, huh?

    Bud--
     
  13. John Gilmer

    John Gilmer Guest

    I have seen (and purchased but not yet use) those "poke in" connectors. I
    don't even know if they are rated for Al. But you seem to be saying that
    the ONLY way to go for the "little stuff" is a hard crimp! Screws just
    aren't "gud enuf."

    Should we start to worry about the "big stuff" used for electric stoves or
    from the meter to the service panel?

    EMWTK
     
  14. Bud--

    Bud-- Guest

    (I don't know what the "poke in conectors" are.)

    The only method recommended by the Consumer Product Safety Commission is
    the COPALUM high pressure crimp system. The crimps replace all wire nuts
    and a copper wire is pigtailed out at devices. They specifically advise
    against using wire nuts. (But see paper below for a wire-nut use.)

    Wire nuts, as well as connections to devices, have caused problems
    including fires. My understanding is the new alloy and CO/ALR devices
    solve the expansion problem but have the same oxide problems. Wire nuts
    with the new alloy should have the same oxide problem as before.

    The best information I have seen is at
    http://www.inspect-ny.com/aluminum/alreduce.htm
    which is a paper based on information derived from extensive tests at
    the Wright-Malta Corp. for the CPSC. I covers a WIDE RANGE OF OPTIONS.

    Anyone with an interest in aluminum wire 15 and 20 amp branch circuits
    you should look at the paper.

    Paper highlights:
    - information on the options to reduce aluminum wiring risk
    - information on COPALUM crimp connections (mentioned above)
    - DETAILED PROCEDURE TO USE WIRE-NUTS WITH ALUMINUM WIRE to pigtail a
    copper wire or to replace existing wire-nuts, including brands to use
    - description of how wire-nuts fail; existing wire-nuts should be
    replaced
    - discussion of problems with Ideal #65 wire-nuts (the only UL listed
    wire-nut for aluminum)
    - how to install Ideal #65 wire-nuts, if necessary
    - detailed procedure to connect aluminum wire to (CO/ALR) switches
    and receptacles
    - procedure to connect aluminum wire to circuit breakers
    - if not making the changes above, what to do with existing system
    - wiring installed after about 1971 with the new wire is more
    reliable (if installed correctly) at device connections, but it has
    essentially the same oxide problems as the old wire; this is
    particularly a problem at wire-nuts; the information above is applicable
    to the new wire
    - also other very useful information.
    I havn't heard of problems with service size and larger aluminum wire.
    The connection clamps have a large area and the procedures to use are
    well known to electricians.

    Stove size stuff I havn't heard of problems. I would use Al listed split
    bolts over wire-nuts and devices must be listed for aluiminum - along
    with antioxide paste. The device connection clamps are a lot better than
    the binding screws used on switches and receptacles. Are circuit
    breakers listed for aluminum wire? Could split bolt a copper pigtail.
    And I would think strongly about applying paste and then abrading the
    wire as described in the paper.

    Bud--
     
  15. Guest

    I don't know where you would even buy 12 or 10 ga aluminium.
    It is a moot point.
     
  16. Guest

    Bear in mind this is a "home inspector" site <insert home inspector
    joke here> It is not an opinion of any nationally recognized testing
    lab.
    Home inspectors live on FUD
     
  17. Bud--

    Bud-- Guest

    Perhaps you could talk about the errors you found at the link above
    insead of presumed problems with home inspectors which may or may not
    include the inspector running the base web site.

    As I clearly said in my last post, the information at the link above is
    the result of extensive experiments done by the Wright-Malta Corp. under
    contract from the CPSC. Or are they both suspect also. Papers on this
    subject, from the Wright-Malta employee (who is not a home inspector)
    that wrote the paper in the link above have been given at IEEE
    conferences and appeared in IEEE Transactions. Based on the tests at
    Wright-Malta, the CPSC requested UL change their standard for testing
    aluminum rated wire-nuts.

    From your other post - "it is a moot point"? 2 million homes are wired
    with old technology aluminum wire from about 1965 to 1973. You may find
    it hard to believe, but failed connections in those wiring systems have
    caused fires and killed people. Because of these problems, UL removed
    its listing on aluminum wire and devices in 1971. UL chaged its
    standards and started listing devices which are marked CO/ALR and the
    wire alloy was changed.

    Aluminum branch circuit wiring continues to be a hazard. The link above
    gives a number of options for handling the wiring in those homes.

    Your apparent disregard of science-based information indicates you may
    have a bright future in the Bush administration.

    Bud--
     
  18. Guest


    Bud this thread was about NEW installations not something during
    Watergate.

    I was referring to the aa8000 alloy


    It should be noted that most of the problems with the older wiring was
    sloppy installation or homeowner intervention. That is witnessed by
    the number that DIDN'T have any problems in the last 3 decades,

    BTW these are the Nationally Recognized Testing Labs
    (NFPA and OSHA)


    MET Laboratories, Inc. (MET)
    800-638-6057
    914 West Patapsco Avenue
    Baltimore, Maryland 21230


    Intertek Testing Services NA, Inc. (ITSNA)
    (formerly ETL, Inchcape)
    800-345-3851
    3933 U.S. Route 11
    Cortland, New York 13045


    Communication Certification Laboratory, Inc. (CCL)
    801-972-6146
    1940 West Alexander Street
    Salt Lake City, Utah 84119


    Canadian Standards Association (CSA)
    (also known as CSA International)
    416-747-4000
    178 Rexdale Boulevard
    Etobicoke (Toronto), Ontario M9W 1R3
    Canada


    SGS U. S. Testing Company, Inc. (SGSUS)
    (formerly U.S. Testing/California Division)
    973-575-5252
    291 Fairfield Avenue
    Fairfield, New Jersey 07004
    Email:


    Southwest Research Institute (SWRI)
    210-684-5111
    6220 Culebra Road
    Post Office Drawer 28510
    San Antonio, Texas 78228


    Wyle Laboratories, Inc. (WL)
    256-837-4411
    7800 Highway 20 West
    P.O. Box 077777
    Huntsville, Alabama 35807
    Email:


    Entela, Inc. (ENT)
    800-888-3787
    3033 Madison, S.E.
    Grand Rapids, Michigan 49548


    Underwriters Laboratories Inc. (UL)
    847-272-8800
    333 Pfingsten Road
    Northbrook, Illinois 60062


    FM Global Technologies LLC (FM)
    (also known as FM Approvals and formerly Factory Mutual Research
    Corporation)
    781-762-4300
    1151 Boston-Providence Turnpike
    P.O. Box 9102
    Norwood, Massachusetts 02062


    TUV Rheinland of North America, Inc. (TUV)
    203-426-0888
    12 Commerce Road
    Newtown, Connecticut 06470


    Electrical Reliability Services, Inc. (ERS)
    (also known as eti Conformity Services and formerly Electro-Test, Inc.
    (ETI))
    925-328-3400
    3470 Fostoria Way, Suite A
    San Ramon, California 94583
    Email:


    Applied Research Laboratories, Inc. (ARL)
    305-624-4800
    5371 NW 161st Street
    Miami, Florida 33014


    National Technical Systems, Inc. (NTS)
    978-263-2933
    1146 Massachusetts Avenue
    Boxborough, Massachusetts 01719
    Email:


    NSF International (NSF)
    800-673-6275
    789 Dixboro Road
    Ann Arbor, Michigan 48105
    Email:


    Curtis-Straus LLC (CSL)
    978-486-8880
    527 Great Road
    Littleton, Massachusetts 01460
    Email:


    TUV Product Services GmbH (TUVPSG)
    49-89-5008-4335
    Ridlerstrasse 65, D-80339
    Munich, Germany


    TUV America, Inc. (TUVAM)
    978-739-7000
    5 Cherry Hill Drive
    Danvers, Massachusetts 01923
     
  19. Bud--

    Bud-- Guest

    The National Fire Protection Association, in the NEC Digest, Spring
    2004, repeated CPSC findings on aluminum wire:
    "In 1974, the CPSC determined that hazards associated with aluminum wire
    systems present "an unreasonable risk of injury or death" and later
    filed suit against more than two dozen manufacturers of aluminum wire
    and devices used in these systems.
    "According to a report published by the CPSC, homes wired with aluminum
    wire manufactured before 1972 ("old technology" aluminum wire) are 55
    times more likely to have one or more connections reach Fire Hazard
    Conditions than is a home wired with copper."
    The NFPA, as you probably know, creates the National Electrical Code. In
    2004 they, along with the CPSC, seem to still feel that aluminum wiring
    poses a risk.
    From alreduce.htm: "The aluminum-wired connections that fail tend to
    progressively deteriorate at a slow rate, and after many years can reach
    very high temperature while still remaining electrically functional in
    the circuits."

    One of the most significant findings of Wright-Malta was that aluminum
    wire connections made in accordance with industry standards and
    manufacturer recomendations can fail, possibly resulting in a fire. That
    is why the CPSC moved to regulate the industry. "Sloppy installation" is
    not required. And "sloppy installation" as a cause remains at the level
    of opinion unless you have an investigative source.
    I have doubts the NFPA recognizes this list. From the 2003 NEC Style
    Manual: "Use of the terms "Nationally Recognized Testing Laboratory" or
    "NRTL" shall be avoided. .... [It] is an OSHA program for the
    accreditation of laboratories that test products for the workplace and
    is not to be applied generally in the NEC."

    I have no idea what the relevance of the list of laboratories unless it
    is to show that Wright-Malta isn't on it. But the list is of labs is
    those recognized by OSHA to qualify a product as meeting a standard -
    for electrical products it is typically a UL standard. That is not what
    Wright-Malta was doing.

    Incidentally, the longer story of of the CPSC involvement is that it was
    alarmed by fires from aluminum wiring systems (including deaths)
    contracted with Wright-Malta to make tests. Wright-Malta wound up doing
    extensive tests of aluminum connections (extensive: "in 1982, there were
    approximately 7,500 aluminum and aluminum-copper connections on
    long-term test, plus (for comparison purposes) a substantial number of
    copper-wired connections.") My understanding is that the CPSC
    recommended a recall of aluminum wire. In the obvious court case that
    resulted, the court ruled aluminum systems were not "consumer products"
    and thus the CPSC did not have perview.

    The CPSC must have considered the Wright-Malta test data to be extensive
    enough and have enough validity to initiate an action against the
    industry and withstand the court case that would obviously result.

    The paper at the web page contested before,
    http://www.inspect-ny.com/aluminum/alreduce.htm
    is based on the Wright-Malta test data extended to practical fixes for
    existing wiring. From section 1H of the paper (which is about the new
    alloy wire you are fond of):
    "[The new] alloy aluminum wire may have lower probability of overheating
    at the binding head screw connections. There is little improvement in
    the probability of overheating in other types of terminations, however.
    In particular, the alloy aluminum conductors show high failure rates in
    tests with twist-on connectors [aka wire-nuts].
    "The alloy wires have improved mechanical properties but may have
    essentially the same electrically-insulating oxide surface film. As with
    the "old technology" ("EC" grade) aluminum wire...."

    The point about wire nuts and oxides is the one I made in my original post.

    Bud--
     
  20. Guest


    I guess that is why you are supposed to torque the fitting to specs.
    That assures a gas tight connection. Since most lugs these days are an
    aluminum alloy and aluminum wire actually tests better than copper in
    one of them, some of this hysteria is misplaced.

    Read the topic title, this is NOT about 10ga and smaller wire. You
    would ber hard pressed to buy some, even if that was what we were
    talking about.

    I know folks love to cite the NY-Inspect site, but I have to bear in
    mind that is the same city that banned Romex for any application until
    very recently so some of this may be IBEW mantra.,
     
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