Fitting electric door strike

Discussion in 'Electricians' Talk' started by mitch2801, Nov 16, 2007.

  1. mitch2801

    mitch2801 New Member

    Hi, Looking for some help.

    I have bought a video intercom system for my parents house for Christmas. However it has no ability to fit a door strike to remotely open the door from upstairs as it is getting a bit difficult for them healthwise.

    My question is....... I have also just bought a 12v electric door strike as their door lock is suitable and plan to install this while fitting the intercom. What would the best type of switch be for them to release the lock and where could I get it? Also if you don't mind, how best to wire the strike? Intercom came with 4 core cable but plan to use some cat6 instead as I have a few boxes at home

    Thanks

    Davie
  2. Rabbit Rabbit

    Rabbit Rabbit New Member

    Gawd knows (and someone will on here). One thing is for sure CAT5 won't be suitable for the strike, it will take a fair amount of current at 12V and will need something like 1.5 t/e. But best wait for someone to come along on here who has fitted one, I haven't.
  3. Badger001

    Badger001 New Member

    i have in the past ran 1.omm 2 core flex for the 12 volt supply, cat 5 is used for the rs485/rs232 or the data line.. and any video signals.
    but under no circumstances should the cat 5 or 6 be used to carry 12 v dc at that amount of current.
  4. oliver1234

    oliver1234 New Member

    i have in the past ran 1.omm 2 core flex for the 12
    volt supply, cat 5 is used for the rs485/rs232 or the
    data line.. and any video signals.
    but under no circumstances should the cat 5 or 6 be
    used to carry 12 v dc at that amount of current.

    It really does depend on the door strike you are going to fit.

    If it's one of those ones that work with a Yale type latch then cat5 will be fine, they use very little current and are usually configured to open when the current is supplied. (as opposed to mag locks which need current to keep them locked).

    Can you give more detail on the type of strike you are using?
  5. Rabbit Rabbit

    Rabbit Rabbit New Member

    Well there ya have it CAT5 may well do the job just as I said lmao!!

    Knew someone would come along eventually.
  6. oliver1234

    oliver1234 New Member

    We used to fit a lot of those cheap door entry kits in the 80s and 90s in flats and suchlike.

    The strikes just had a very small electromagnet in them and only drew about 75ma so we used 8 core alarm cable which did the speach and everything.

    Mag locks can draw a lot more though (though not as much as you might think)and volytage drop can be an issue in which case you would need to look at the cable size.
  7. mitch2801

    mitch2801 New Member

    Thanks for the info lads. Below is the link to the one I bought.....
    http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=120182430954&ssPageName=STRK:MEWA:IT&ih=002

    Had not planned on using the Cat6 for the strike. Intercom came with only 15m of thin ribbon cable which is not long enough, need about 25m, so planned on using cat6 for the intercom and some advice from you guys for the strike. Also after advice on best place to get a push switch to release the door, obviously one which springs back out again. I have emailed the guy I bought it from to ask the ampage on the 12v supply I need to get.

    Once again thanks for your help and advice
  8. oliver1234

    oliver1234 New Member

    From looking at your link it is impossible to say whether the strike is designed for AC or DC, they are available for both.

    Either way the cable requirements are minimal, standard alarm cable or CAT5 will be fine for this type of strike.

    As the strike is configured in the picture it is for a "yale" type rim latch but with the other part fitted it will work with a mortice latch.

    Most of these type latches are configured as fail locked which means you have to apply power to unlock it in which case you could use a normal bell push at 12 volts.

    If it is fail locked which some are you will need a retractive double pole switch (ask at an electrical wholesaler)

    As regards the power supply you really need to ask the supplier the following: 1 Is it AC or DC (if it's designed for ac and you use a dc supply it will overheat)

    You also need to know whether it fails locked or open.

    I know it may seem a waste of money but it might be easier to get a complete kit and just use the bits ytou need.
  9. Bando

    Bando New Member

    Just buy a door bell transformer in ac or dc to suit ur strike. Thats what usually comes in the intercom kits. Any push to make switch will do. I did one with 1 of the cheap Makro video intercom's a few weeks ago. It was supposed to have the ability to power a door strike. However it does not produce enough current. It can work if u use a second transformer and relay.
  10. mitch2801

    mitch2801 New Member

    Thanks for the replys guys.

    Phoned the seller up and he is sending me the 12v supply and the release button so that part is sorted now.

    Only other thing I need is a wiring diagram for the strike to the switch if you don't mind. I am using Cat6 to run the Intercom so will have 2 pairs spare and plan on using 2 of these. The strike stays closed on no power and open with power.

    Thanks once again
  11. oliver1234

    oliver1234 New Member

    If your strike is DC it may have a diode across it to stop back emf in which case it is polarity conscious.

    This just means you need to be aware that you connect the positive of the transformer to the positive of the strike.

    1- Connect the negative of the transformer to the negative of the strike.

    2- Connect the positive of the transformer to either connection on the release button.

    3- Connect the other side of the release button to the positive of the strike.

    If it is an AC strike connect as above but ignore references to positive and negative.

    The strike you describe will be fine with cat5, it only draws current whilst the button is pushed and even then it is very minimal current.

    by the way, if it is an AC strike it will buzz as you open it, this is normal.

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