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  1. #1
    Join Date
    Jul 2010
    Location
    Haw River, NC
    Posts
    30

    Should I use a two-pole contactor on a single-phase 240V motor?

    I also asked this question on mikeholt.com, but I wanted to see what HVAC-talk thinks.

    I was asked recently why I was using a two-pole contactor to control a 1 240V motor (versus a marginally cheaper single-pole contactor).

    Not using a two-pole contactor feels wrong to me, and from a safety perspective I don't want to not switch any ungrounded conductors--that's the same to me as switching a neutral in a hot-to-neutral circuit.

    Is this (not switching all ungrounded conductors) a bad idea?

  2. #2
    Join Date
    Aug 2012
    Location
    North Dakota
    Posts
    518
    Yes I'm with you on that though it is comonly done anywhere to save a dime

  3. #3
    Join Date
    Sep 2005
    Location
    Atlanta GA area
    Posts
    21,278
    Something to think about:

    Any time we alter the factory design (regardless of what anyone thinks, or what the facts are), we put ourselves in a position of liability.

    If the factory built the unit with a single pole contactor, then to change it to a two pole (regardless of safety) will place the tech at liability for safety; because the UL certification has been altered.

    Yeah, that does not make a lick of sense... however when one is in a courtroom common sense is not the issue... whatever the law dictates IS the issue.

    If we can get rid of the lawyers... then we can operate common sense again... (not holding my breath).
    GA-HVAC-Tech

    Quality work at a fair price with excellent customer service!

    Romans Ch's 5-6-7-8

    2 Chronicles 7:14

  4. #4
    Join Date
    Aug 2012
    Location
    North Dakota
    Posts
    518
    yes that's a fine point there ga-tech dont want to marry any-thing

  5. #5
    Join Date
    Feb 2010
    Location
    Calgary, Alberta
    Posts
    1,115
    Aren't the single pole contractors used when the mfg is too cheap to put a real crank case heater in, and uses one compressor winding for that purpose?

  6. #6
    Join Date
    Apr 2012
    Location
    winnipeg
    Posts
    1,330
    man...... put a 2 pole contactor in.... no liability issues in Canada..... single pole is just wrong in my opinion....
    it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair

  7. #7
    Join Date
    Nov 2001
    Location
    Moose Jaw, Saskatchewan, Canada Occupation:Interprovincial Plumber, Commercial Gasfitter Interests:
    Posts
    2,412
    Quote Originally Posted by carmon View Post
    man...... put a 2 pole contactor in.... no liability issues in Canada..... single pole is just wrong in my opinion....
    Since when is there no liability?
    I love my job, but paydays Thursday

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