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Gate Sensor?

Discussion in 'Security Alarms' started by Steve, Nov 14, 2009.

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  1. Steve

    Steve Guest

    RV storage area with two 15ft gates mounted to metal gate posts not attached
    to the main building. Looking to put a contact on it. Anything readily off
    the shelf?

    GRI makes 3/4 and 1 inch contacts for metal doors. Anybody make 1/2 inch

  2. G. Morgan

    G. Morgan Guest

    I'd use an overhead door contact, for the durability and the extra "gap"
    you'll need for a gate.
  3. Steve

    Steve Guest

    How should I get from the gate into the post? Some sort of flexible look I
    would think, but not sure where to find it.

  4. G. Morgan

    G. Morgan Guest

    A picture would help.

    Generally you can fish the wire through the insides of the gate's tubing. It's
    best to use "armored" cable for coming out of the tubes, and as a flexible
    conduit for transitions to boxes, etc... You can buy the small empty cable
    armor at ADI, and just run a 22/4 thru it. (It's the same size that comes with
    the OH contacts. Don't know the part # off hand).

    Or you can use PVC conduit, and boxes mounted right to the gate, but it won't
    look as pretty.
  5. motley me

    motley me Guest

    How bout this:

    Part Number 8450-2 Gate Mounting Kit Consists of:
    1 S4402-A SPDT Switch
    1 M-4400 Magnet
    2 S-202 Brackets
    4 #6-32 x 5/16 Zinc Hex Nuts
    4 #6 External Lock Washers
    4 #6-32 x 3/4 Phillips Machine Screws
    2 #8 x 1 Self Tap Combo Panhead Type A Screws

    GRI contact for gates.
  6. CH®IS

    CH®IS Guest kits.htm
    ....These ones?

    There is one complaint I've had regarding these gate contacts... changing
    seasons is not kind to them.

    Every six months or so we get calls from whereever we have these installed
    to come out and fix them. Turns out that the gates and fences move so much
    that the contacts won't line up to the magnets anymore. Eventually the
    fence post has dozens of extra holes in it.

    Also, do not use the supplied bolts to secure anything to anything. They
    will break halfway through installation.

    The pull apart switch may be a good solution for you...

    I haven't installed one of these yet, but have built something similar with
    good success. We've had one floating around in the office for at least the
    past five years (the 4704-A by the looks of it), mixed in with a random
    assortment of odd contacts and switches. Looking at how it's designed
    though, it looks like it would work very well. In case someone's thinking
    of just unscrewing it off the post, it has that covered already. Remove the
    four obvious screws and you'll find that you need to disconnect the switch
    in order to remove the hidden screw. Too late though, the zone is already

    - Chris
  7. motley me

    motley me Guest

    Amen to that
    I'm not the OP, but you might bet right, especially if it is a walk thru
  8. alarman

    alarman Guest

    I have used unistrut channel to mount the contacts. If adjustments are
    necessary later, you can usually move the channel without re drilling. It
    also gives you a more stable mounting surface for the contact and magnet,
    and facillitates allignment.
  9. CH®IS

    CH®IS Guest

    Very true. It comes down to a matter of getting them to get their staff
    into the habit of using them. Other people aren't a concern, these are
    always gates that are only closed when the business is closed... and are
    Do you have a link for these contacts? It's been awhile since I've had to
    play with one of these gate contacts but I don't believe they get close to
    3" of a reliable gap.
    Connecticut winters? I spent a couple minutes on google trying to figure
    out if those exist. I'm quite sure they don't.

    Speaking of winters though, the other problem we have is with beam systems.
    The posts are always moving around with the weather. Turns out the best way
    to protect something is to remove the fence and build a wall.

    - Chris
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