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Thread: Underground vs Overhead Service Connection

  1. #1
    Join Date
    Mar 2015
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    Underground vs Overhead Service Connection

    I notice that many site survey forms have a place where you check off if the service drop is overhead or underground. Why is this? What are some actions you can and cannot do based on an underground vs. overhead service drop? (with regards to solar)

    Regards,
    Andy

  2. #2
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    Oct 2009
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    Austin, TX, USA
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    Quote Originally Posted by andrew.tkelly View Post
    I notice that many site survey forms have a place where you check off if the service drop is overhead or underground. Why is this? What are some actions you can and cannot do based on an underground vs. overhead service drop? (with regards to solar)

    Regards,
    Andy
    I think it's more of a point of information to utilities/AHJ's so that they know what to expect when they get there to do an inspection. There is no difference that I know of between connecting to an overhead vs. underground service.

  3. #3
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    Mar 2015
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    Berkeley, CA
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    Could it affect anything when it comes to doing a panel upgrade/swap? Or if you have to move the main panel a little? For example, some main electrical panels here in California are located only a couple feet above the gas main. Not sure why. I wanted to do a panel swap, but the AHJ said I would have to move the panel at least 3-ft away from the gas main, therefore the main panel would have to be moved if we did a swap/upgrade.

    Andy

  4. #4
    Join Date
    May 2011
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    Very simply, upgrading an underground service is many thousands of dollars and if there is any possible need to do it then you need to stop right there and fully evaluate before moving forward.

    Examples of the kind of disasters you want to avoid:

    1) The underground service on a residence is 60 years old and only rated for 50A. The service panel is a piece of crap so you want to replace it but the minimum code requirement for a dwelling is 100A, so the inspector will not green-tag a new service panel unless the underground service conductors are upgraded.

    2) An owner has added a 100A car charging circuit to a 125A service, without a permit. The main breaker is not tripping or anything, but if you show this panel an inspector there's a good chance that no final inspection will get approved unless the service is upgraded to 200A.

    In either case, it's a disaster to put solar panels on the roof before you are sure either that the AHJ agrees not to require upgrading the underground service, or that the customer will pay for it.

  5. #5
    Join Date
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    Quote Originally Posted by jaggedben View Post
    Very simply, upgrading an underground service is many thousands of dollars and if there is any possible need to do it then you need to stop right there and fully evaluate before moving forward.

    Examples of the kind of disasters you want to avoid:

    1) The underground service on a residence is 60 years old and only rated for 50A. The service panel is a piece of crap so you want to replace it but the minimum code requirement for a dwelling is 100A, so the inspector will not green-tag a new service panel unless the underground service conductors are upgraded.

    2) An owner has added a 100A car charging circuit to a 125A service, without a permit. The main breaker is not tripping or anything, but if you show this panel an inspector there's a good chance that no final inspection will get approved unless the service is upgraded to 200A.

    In either case, it's a disaster to put solar panels on the roof before you are sure either that the AHJ agrees not to require upgrading the underground service, or that the customer will pay for it.
    That sort of thing hasn't been a problem for us. The most common service size we encounter is 200A and although we sometimes have to upgrade an MDP, we very seldom have to change out the service conductors. But your point is well taken; it's a very bad idea to start a project without knowing how it will end.

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