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Thread: NEED LIGHTING CONTACTOR HELP

  1. #1
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    NEED LIGHTING CONTACTOR HELP

    Hi, my question is about lighting contactors. I have 3 lighting circuits 6,8,10 all fed from the same panel. Obviously I would like to put them on a shared neutral. The lighting in the building is controlled by a time clock and contactors. Is it allowable for these 3 ccts to share a neutral? I would need to have 3 separate contactors, correct? One cct per coil? Help is appreciated! Thanks!!

  2. #2
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    First are you feeding these circuits off of 3 separate breakers or off one 3 pole breaker?


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  3. #3
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    Casual, yes, you can share a neutral, and you can use a single 3-pole contactor. I'm not sure a 3p breaker is required.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  4. #4
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    Quote Originally Posted by LarryFine View Post
    I'm not sure a 3p breaker is required.
    I do not think so either, handle tie is okay.
    "Electricity is really just organized lightning." George Carlin


    Derek

  5. #5
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    My understanding is if you share a neutral with multiple circuits all ungrounded conductors have to be disconnected at the same time either by using a 3p breaker or handle ties


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  6. #6
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    Quote Originally Posted by ElectricMatt View Post
    My understanding is if you share a neutral with multiple circuits all ungrounded conductors have to be disconnected at the same time either by using a 3p breaker or handle ties


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    Correct.

    New for 2008 NEC 210.4 (B)

  7. #7
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    Quote Originally Posted by Casualsparky View Post
    Hi, my question is about lighting contactors. I have 3 lighting circuits 6,8,10 all fed from the same panel. Obviously I would like to put them on a shared neutral. The lighting in the building is controlled by a time clock and contactors. Is it allowable for these 3 ccts to share a neutral? I would need to have 3 separate contactors, correct? One cct per coil? Help is appreciated! Thanks!!
    I assume you have a 3PH 4 wire WYE power system.
    Just curious is the panel a 120/208V or 277/480V?

    You are wanting to control these 3 lighting circuits from an existing time clock. Circuits 6,8,10. All 3 loads on or all 3 loads off at the same set time.

    You are going to use a contactor ( 3 pole) or individual contactors that will be controlled from the time clock.

    Not sure why you think the 3 circuits need to share a common neutral.
    Circuits 6, 8, 10 may already be a 4 wire multi wire branch circuit or they may not. Maybe 2, 4, 6, is now a 4 wire multi wire branch circuit. Maybe circuit 8 is sharing a neutral with another circuit. Maybe 8, 10 or 8, 10, 12?

    Contacts of a contactor could care less about the neutral.

    Is the existing lighting time clock located next to, near, the panel, with circuits 6, 8, 10? Are other lighting circuits that are controlled by the time clock fed from the same panel? Therein there are other lighting contactors controlled by the time clock?

    Is there a common control circuit that feeds the coils of the other lighting contactors?
    Last edited by Jamesco; 02-17-18 at 03:54 PM.

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