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Connecting #1gage to PCB

Discussion in 'Electronic Design' started by Boris Mohar, Mar 8, 2007.

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  1. Boris Mohar

    Boris Mohar Guest

    My customer desires to secure #0 or #1 gage stranded copper wire to a PCB.
    Other than striping the insulation, it is desirable that no other
    preparation of the wire is permitted. Is there some kind of approved
    transitional component that can be securely fastened to the PC board,
    provide a good interface to the copper pour on both sides and be capable of
    handling such heavy wire?



    Regards,

    Boris Mohar

    Got Knock? - see:
    Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

    void _-void-_ in the obvious place
     
  2. Tim Wescott

    Tim Wescott Guest

    There are compression terminal blocks that you can use in such cases.
    I've never seen one that goes up that big that's just stuck on a PC
    board -- from a purely mechanical perspective I would feel comfortable
    supporting a PC board with such a block, but doing it the other way
    around brings up an image of a seriously broken PC board to mind.

    Newark lists some standard ones that put the terminals on 5mm centers --
    you could probably go from there to the manufacturer to the part that
    you wanted.

    --

    Tim Wescott
    Wescott Design Services
    http://www.wescottdesign.com

    Posting from Google? See http://cfaj.freeshell.org/google/

    "Applied Control Theory for Embedded Systems" came out in April.
    See details at http://www.wescottdesign.com/actfes/actfes.html
     
  3. John Larkin

    John Larkin Guest

    Wire wrap it?

    Weidmuller may have something useful, but their web site is so bad
    that I'm not going to volunteer to find any links.

    John
     
  4. Look in the PV related DC terminal blocks. Compression fittings are the norm
    for NEC. You may end up with a block of copper screwed to the PCB, one hole
    for the wire and another for the compression allen screw.

    Cheers
     
  5. Robert Baer

    Robert Baer Guest

    There are (large) special terminals, with a hole for the wire and a
    screw (in the body) that clamp down on the wire.
    I think ther are some with PC mounting tabs that make them
    mechenacially acceptable, and flow soldering will take care of the rest.
    So far, what i have been able to find in the Mouser catalog, is a
    crimp-on ring, where a screw could go thru the hole and coresponding
    hole on a PCB.
    Hmm..look on page 1226 figures J and K which are close to what i
    first mentioned (no mounting stakes tho).
    Go to the Panduit site and search for the CX125-14-QY copper lug;
    very much like the items just mentioned, but with a very nice close-up
    photo.
    Download their 2-page PDF to see the variants that are available.
    Press-fit turret lugs are another possibility, i think that some have
    a hole large enough to accept such a large wire sise, and then it would
    have to be sweat-soldered in place.

    Be advised that the copper foil beneath the lug needs to be thick and
    rather wide to carry large currents.
     
  6. Boris Mohar

    Boris Mohar Guest


    Thank you very much. That is something that I was looking for. The
    copperpour will be 4 oz.



    Regards,

    Boris Mohar

    Got Knock? - see:
    Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

    void _-void-_ in the obvious place
     
  7. Why? If you want to measure current you can do a '4 wire' setup and avoid
    that sort of connection.
     
  8. Boris Mohar

    Boris Mohar Guest

    I do not need to measure the current. I need to deliver it to the PCB. This
    is for a electric furnace control board. The six elements will be switched
    with individual relays. It adds up.
     
  9. Rich Grise

    Rich Grise Guest

    I'd go to the trouble of providing a substantial physical (mechanical)
    mounting for the wire itself, such that it's positioned to hold the
    terminal in its "natural" position where it connects to the board.

    There's no way I'd depend on anything less than about 7/16 - 1/2"
    epoxy glass to secure a monster like that. Geez, just stand the wire
    up and screw the board to it! ;-)

    Anyway, let us know what you decide, and how it comes out, m'kay? :)

    Good Luck!
    Rich
     
  10. Rich Grise

    Rich Grise Guest

    Terminal blocks you say? ;-)
    http://www.curtisind.com/products/tblocks/S/serieshome.asp

    Cheers!
    Rich
     
  11. Use wire. Truly. The repair people will bless you.
     
  12. Cheap and effective or expensive and effective?

    Why would you want to stripe the insulation?

    Jim
     
  13. Strip presumably.
     
  14. That might be what your customer would like, but
    you might want to check local industrial cabling
    regulations first. I have worked on several jobs
    where stranded cables were required to be first
    secured inside a crimped ferrule. This is to
    prevent loose strands from accidentally shorting
    to another terminal.
    Bringing in multiple cables instead of one big one
    could make life a lot easier.
     
  15. D from BC

    D from BC Guest

    0 AWG = 8.2mm diameter
    There might be something at the electrical distributor...
    Here's one scrappy example...
    I'm not sure but I think I've seen a metal BX cable strain relief for
    electrical boxes that could act as a cheap wire clamp.
    Comes with ring like nut and can be fastened thru a hole in the PCB.
    It'll bridge the PCB sides. It probably can be soldered on.
    D from BC
     
  16. Fred Bartoli

    Fred Bartoli Guest

    Homer J Simpson a écrit :
    and the prod people will trash him every day...
     
  17. Ross Herbert

    Ross Herbert Guest


    I would agree with you Rich.

    For making cable connections to a PCB using such a large gauge it is
    better to have the wires ends mounted in substantial brass terminal
    blocks which are in permanent fixed positions. When the PCB is mounted
    in its final position the brass terminal blocks are then secured to
    the PCB pads with appropriate sized screws and locking washers. You
    certainly don't want cables coming from a cable form or some-such
    arrangement and then trying to secure the flying ends to the boards.
    Fix the cables solidly in place and then bolt on the PCB as though you
    were using solid copper bus-bar instead of flexible cable.
     
  18. MassiveProng

    MassiveProng Guest

    I would certainly use .090" PCB construct form factor to start.

    Two methods. The industry standard is to crimp a lug on the cable
    end and either solder the flat lug to the PCB or clamp it through a
    plated hole with a copper stud/screw/nut. The wire then need a huge
    strain relief clamp directly after the connection within the first few
    inches of the board. That way both the PCB and the connection never
    sees any mechanical stress. If the cable has to be free all the way
    up to the board, you are asking for a failure mode.

    To do it with no crimped lug, I would still us .090", and place a
    good 2,25 sq inch (1.5x1.5) unmasked area on the board with a series
    (array) of at least .200" plated holes in the area. Un furl the cable
    strands, and make a series of "dredlocks" to place into the holes.
    For vertical, perpendicular entry, you fan out the dredlocks, fit them
    through the holes, and commence solder operations after using liberal
    amounts of externally applied flux. For a horizontal, co-planer (as
    it were) entry method, the same dred locks can be used, but would need
    to be longer. In BOTH cases stantioning/fixturing of a cable that
    large is required

    You need a huge iron and tip for this, and I would recommend s good
    ACTIVE flux, and the cable must be new copper.

    A third way would be to maybe make a small 0.090" inch PCB not much
    bigger than the cable diameter... say 0.250 or 0.375 apron bigger that
    you would fit onto the end of the cable, and then mate it to a hole in
    a 0.090" "main board" that is the rest of your layout. The cable end
    PCB would then get SMD mounted to the main PCB.

    All cases require very good fixturing on both the PCB and cable as a
    single immobile pair respective to each other. A cable that big may
    not break free from the pcb, but it may well tear up the PCB
    surrounding elements through flexure. That's why I suggested the
    0.090" material.

    You can strengthen the board by adding layers inside too, but then
    cost goes up.

    A fourth way would be to solder the dread locks onto some 0.040" or
    0.050" (or more!) copper sheet square or round cut with holes drilled
    in it, and SMD that onto the PCB. You could even give it rows of
    perimeter teeth that way

    That would be:

    Holey slab-o-copper with toothy apron, 0.2 inches bigger than the wire
    dia. with 0.200 long teeth which get bent down 90 degrees all around
    (square is easier but round is doable).

    A PCB with your circuit or feeds to it, and a square plated hole
    pattern to match the teeth (like 24 teeth a couple mm wide each) and a
    big through hole in the middle to clear the big wire array.

    The solder flow makes perfect standard through hole solder joints on
    all the teeth, and a nice SMD fill on the part of the copper plate
    that overlaps the PCB on th top side, VERY strong method, but a
    custom part. But hey, so is the PCB!

    The apron on the PCB which accepts the SMD fillet(s), the through
    holes, and even an extended area can be fitted with an array of plated
    VIAs that allow for better thermal handling, and likely add some
    strength and ampacity.

    You could make a strain relief in the form of a bunch of solid copper
    (tinned of course) wires that go from this attachment PCB over to your
    main PCB at like a two inch vault. Like 15 or twenty 18 Ga pieces.

    Bend a slight S shape in the center of each. That separates your
    main board from any flexure problems and makes the whole thing more
    serviceable.

    Any way one looks at it, such a big cable is not an easy attachment.

    Fanning it out into the "dred lock" thing will give it some flexure
    capacity too as long as you do not let the solder wick up into them
    too far (not easy).

    The crimp method is actually far more serviceable, needs no soldering,
    and is only one additional part, and a hug crimper away.

    All the VME chassis us 0.090" PCB media. They clamp copper bars to
    the board, and the tie the wire terminal lugs onto that via studs.

    You could do that too. Make the bar/PCB combo fit your rules of
    attachment to both sides via the clamping methods used, and either
    stud it, or drill and tap it for a bolt and crimp a ring lug on the
    wire and viola!

    OR you could make the bar/PCB combo, and add a CLAMPING bar to the
    top of that, that you fit the wire into. Two tightened bolts later,
    and she's clamped!

    That one is likely the most serviceable. Make sure to use
    antioxidant on that one though.
     
  19. MassiveProng

    MassiveProng Guest

    If it is green, a yellow helical stripe is common. :-]
     
  20. MassiveProng

    MassiveProng Guest


    Nickel plated copper bars.
     
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