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Modular house - intercoms won't work from front to back.

Discussion in 'General Electronics Discussion' started by MamaBear 2015, Nov 21, 2015.

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  1. MamaBear 2015

    MamaBear 2015

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    Nov 21, 2015
    Hi people. I just joined the forums here. I'm a former electronics R&D technician of 27 years - ASEET ( Associate in Science in Electronics Engineering Technology, from 1969 ), who hasn't worked in that field since the mid-90's when most of it went overseas.

    We bought this UBC ( universal building codes ) modular house about 10 years ago and the "builder" installed it on a foundation on the lot we bought. He said he would do it in 6 months and took 18, while we paid a construction loan, ripped us off for tens of thousands of dollars in the process, AND did his own plumbing and electrical, apparently paying licensed people for their signatures for city inspection purposes. ( we hope he rots in hell )

    The house came from the factory in two halves that were joined together on the foundation - the front and back halves. He hooked up the AC to everything.

    Anyway, since moving in, the AC has been weird between the front and back halves. A doorbell that had the transformer plugged in, in the laundry room in the back, wouldn't work right because the front door was in the front half.

    And we've tried using some Westinghouse power line intercoms but they only work if plugged into the respective half where the other one is, not across the halves.

    So this is kind of a mystery, but I'm suspecting that he may have run a common ground and fed each half with a separate phase of AC from a 120VAC transformer ( from the power line transformer out on the pole? ).

    I just don't know how to deal with this, without great expense.


    We really want our intercoms to work, especially since our area has had some bank robbers that the police have been doing a manhunt for, and they've been doing home invasions, and my sister's room is at the opposite end of this 80 foot long house, from mine.

    Any ideas on how we can solve this quickly and inexpensively?

    My first thought would be to put a large enough high voltage non-polarized capacitor between the hot lines of each half of the house, but the house has insulation in the crawl space down there and plastic sheeting over it, and I'm 68 years old and not good at crawling around in such an environment.

    Thanks.
     
  2. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    So sorry to hear about your luck.
    I'd try and pursue not only the builder but the licenced people who signed the permits.
    Anyway, I'm not sure but I suspect the intercom is not working because both transceivers are not on the same phase.
    Most houses (US) are fed with split phase, where the transformer has a mid-tap that devides 240v into two 120v sides with respect to a neutral common.
    The wiring can probably be altered at the main service panel so that the receptacle in your room and the one down the hall are on the same side (phase)
    I would verify that the intercom works firstly. You can experiment by plugging into different outlets to check.
    Then you can have an electrician swap a few wires for you.

    John
     
  3. MamaBear 2015

    MamaBear 2015

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    Nov 21, 2015
    Tha, this was 10 years ago when the house was built, so we cant do anything. The "builder" lost his license in this city, after doing our house but he had everything in his wife's name, so we couldn't sue him.

    Yes, I agree that it's probably wired that way, but it would cost a fortune to alter it now.

    I did verify that both intercoms work, by plugging them both in on the same side of the house.

    I just need an inexpensive solution to this, that doesn't require modifying wiring at this point.
     
  4. Bluejets

    Bluejets

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    Oct 5, 2014
    Run an extension lead.
     
  5. GPG

    GPG

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    Sep 18, 2015
    Have you got a single distribution panel?
     
  6. Alec_t

    Alec_t

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    Jul 7, 2015
    Use a wireles intercom?
     
  7. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    By modifying, its probably only necessary to move one wire up or down two inches to the next circuit breaker (on opposite phase.)
    An Electrician can do this in a minute or so.

    As far as how you got scammed, I'd at least consult a lawyer on the matter.
     
  8. MamaBear 2015

    MamaBear 2015

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    Nov 21, 2015
    Yes.
     
  9. MamaBear 2015

    MamaBear 2015

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    Nov 21, 2015
    We have 4 of these Westinghouse intercoms here, from trying this a few years ago. Just had forgotten about it, but we need to be able to talk the length of the house, in case of emergencies, a break-in or whatever.
     
  10. MamaBear 2015

    MamaBear 2015

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    Nov 21, 2015
    Not sure what you mean. Like running the entire house on one phase? That's interesting - I'll check that out with an electrician. Thanks.

    10 years is WAY past the statute of limitations, but thanks.
     
  11. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    Not running the whole house, just moving that one circuit from from A side to B side (phase) of a different circuit breaker.
    Breaker panels usually have one phase on even number breakers and the other phase on odd numbers. So, the A phase is on 1,3,5,7,9,11... and the B phase would be on 2,4,6,8,10..... In other words, from top to bottom, every other breaker is on the same phase.
     
  12. Bluejets

    Bluejets

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    Oct 5, 2014
    Trouble with that is, most only have a couple of power circuits and as built should have been approxiately balanced over the 2 phases.
    Move one onto the other phase and all will more than likely be on one phase.
    It all depends on how it's been wired, and only a qualified lecky will be able to sort that out.
    Extension lead looks like the quick cheap fix.
     
  13. Tha fios agaibh

    Tha fios agaibh

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    Aug 11, 2014
    Right. Electrician will swap a similarly loaded circuit with the other, and all is well. Usually general lighting load circuits are comprised of mostly receptacle outlets. Balancing is an insignificant factor in these types of loads because most outlets are unused.

    Extension cord not a good idea because someone will end up tripping over it.
    Besides, they are for temporary use only.
     
  14. chopnhack

    chopnhack

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    Apr 28, 2014
    When X10 was popular, they used to make phase couplers for just this purpose. To tie the signals from both sides of the service together. Search the web for a phase coupler and you can see what they are. Do you have a model number for the intercom?
     
  15. MamaBear 2015

    MamaBear 2015

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    Nov 21, 2015
    Didn't know that. Well the whole house would need to be on the same phase, to use these intercoms anywhere in the house.
     
  16. MamaBear 2015

    MamaBear 2015

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    Nov 21, 2015
    Ahah! Yes! Sounds exactly like the high voltage non-polarized cap that I was thinking of!

    WHI-2C
    ...

    heh, look at what I just found!: http://www.ebay.com/itm/X10-Phase-C...208413?hash=item2547d939dd:g:F94AAMXQhpdRvhWP

    According to the calculator at http://www.sengpielaudio.com/calculator-RC.htm

    .015 uf at 60 Khz is 176 ohms reactive impedance, but at 60 Hz it's 176k. :)

    Oh wait, this is even better. The manual at http://phone.manualsonline.com/manuals/mfg/westinghouse/whi2c.html

    says they operate above 200 Khz. So... .015uf at 60 Hz is 177k but at 200 Khz is 53 ohms. Nice!
     
    Last edited: Nov 22, 2015
  17. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    The Westinghouse Powerline "wireless" intercoms use FM over the power lines on four channelized carrier frequencies (200kHz, 230kHz, 260kHz & 290kHz). You need a phase coupler installed in the breaker panel to pass the FM from one phase to the other. A low value capacitor with a 1000V rating should present a low impedance to the RF signal while passing minimal 60Hz energy. Some of the commercially available phase couplers such as the ones made for X10 systems may suffice. A home automation specialist could advise you.

    Edit: That 100nF capacitor might do it. It provides 8Ω impedance at 200kHz and almost 28k impedance at 60Hz. That's still 2W being dissipated in the capacitor. I'm not seeing 15nF anywhere.
     
    Last edited: Nov 22, 2015
  18. Bluejets

    Bluejets

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    Oct 5, 2014
    Balancing circuits for power is not done on the basis of what is plugged in although I tend to keep laundry and kitchen sections seperate.
    When a house is wired it is done on the basis of number of points.
    Attempting to balance light against power circuits is a waste of time given power at 1000w average and lighting (especially now LED ) at 60w per point.
    Better an extension lead than letting the op attack his sw board I would think.
     
  19. MamaBear 2015

    MamaBear 2015

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    Nov 21, 2015
    I found these in my old lab but don't recall why a non polar cap like that has a VDC rating. Can it be used for AC?

    [​IMG]
     
  20. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    Yes. The rating is for dielectric breakdown.
     
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