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  1. #1
    Join Date
    Feb 2010
    Location
    Long Beach, CA
    Posts
    105

    Default So, that's not a disconnect?

    The builder's electrician phoned me to complain that the detached home's (the city calls it a townhouse although the two houses on the property are free-standing) 100amp 120/240 disconnect at the back exterior wall of the garage does not require a grounding system because that happens at the branch panel within the garage. He calls the building's outdoor disconnect a switch for convenience only and that's the way he's done it for 35 years. So, the first picture is the outdoor disconnect with an unsecured back-fed breaker were the underground 4-wire laterals terminate. From there, 4-wires go to the garage branch panel where the neutral bar is bonded to the frame and grounding conductor (second photo), When I asked him how is it the outdoor disconnect shuts down all power but yet is not regarded as a disconnect and not provided a grounding conductor and how is it the garage branch panel can have bonded grounds and neutrals...he's comment was that '..it's bonded at the branch panel so it's taken care of. ' WOW. I asked him to email me supporting code references. Ahhhgrrrr.... Note: The meter and it's main disconnect are at the other home.

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  2. #2
    Join Date
    Aug 2008
    Location
    Maryland
    Posts
    1,898

    Default Re: So, that's not a disconnect?

    Based on your description I would say it is time for some continuing ed classes for the contractor.

    All answers based on unamended National Electrical codes.

  3. #3
    Join Date
    Apr 2008
    Location
    Western Massachusetts
    Posts
    536

    Default Re: So, that's not a disconnect?

    Has the code not changed in 35 years?


  4. #4
    Join Date
    Mar 2011
    Location
    Virginia Beach, VA
    Posts
    123

    Default Re: So, that's not a disconnect?

    Marc,

    Based on what I see in the photos, the electrician is incorrect.

    First, his statement regarding the switch as being, "For convenience only" is bogus since he has not provided a method to kill the main panelboard.

    (If as the electrician states, the switch is but a mere convenience, then) [added as PS], because there are more than six breakers, this panelboard cannot qualify as a Main Lug Only panelboard.

    Also, Since the main disconnect is outside, the grounding and bonding must originate at the Main Disconnect, furthermore that panelboard shown in the second picture is incorrect.

    Since this panelboard is downstream of the Main Disconnect, Ground and Neutral must be isolated from each other. Which of course means that anywhere in the panelboard where Neutrals and EGCs are present on the same bus, must be changed.

    Since this panelboard is downstream of the main cutoff, it is treated as a secondary panelboard, not a Main Panel board.

    Last edited by Donald Farrell; 10-11-2011 at 01:01 PM.

  5. #5
    Join Date
    Oct 2011
    Location
    Eastern Shore of MD, NEC 2008
    Posts
    94

    Default Re: So, that's not a disconnect?

    Quote Originally Posted by Donald Farrell View Post

    Also, because there are more than six breakers, this panelboard cannot qualify as a Main Lug Only panelboard.
    You want to clarify that?

    I hope you meant to say that a MLO panel board that serves as a service disconnecting means cannot have more than six breakers. Old split busses are a bit of an exception, but the upper buss cannot have more than six breakers as a service disconnecting means.

    Since this panel is not the service disconnecting means the MLO panel board can stay, but the other issues must be addressed.


  6. #6
    Join Date
    Mar 2011
    Location
    Virginia Beach, VA
    Posts
    123

    Default Re: So, that's not a disconnect?

    Sorry, I was being "Tongue-in-cheek". I'll go back and re-do the comment in a minute. Thank you for pointing out the error.

    However, since this installation is in fact a Main Disconnect, there must be a four wire feed from the Switch to the panelboard and the Neutral and Ground buses must be isolated from each other, agreed?


  7. #7
    Join Date
    Oct 2011
    Location
    Eastern Shore of MD, NEC 2008
    Posts
    94

    Default Re: So, that's not a disconnect?

    Quote Originally Posted by Donald Farrell View Post
    Sorry, I was being "Tongue-in-cheek". I'll go back and re-do the comment in a minute. Thank you for pointing out the error.

    However, since this installation is in fact a Main Disconnect, there must be a four wire feed from the Switch to the panelboard and the Neutral and Ground buses must be isolated from each other, agreed?
    Yep. And the GES must be established at the switch as you stated.

    I felt that you were just a little unclear in the post on the MLO panel and that you actually knew the rules. Everything was spot on correct except that slightly muddled part.


  8. #8
    Join Date
    Feb 2010
    Location
    Long Beach, CA
    Posts
    105

    Default Re: So, that's not a disconnect?

    It's just outrageous that I even had this discussion with a licensed electrical contractor. No doubt that within the scope of his trade, his knowledge base is way deeper that I can appreciate...but seriously--a 'convenience switch'?. Of course he has not followed up with any code references proving his point so that's one more exchange I've dodged where he talks in circles and I keep repeating "Where in the code is that allowed?"
    Thanks Jim, Corn, Donald & Derek for the input.


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