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Thread: Utility power disconnect

  1. #1
    Join Date
    May 2013
    Location
    Tujunga, CA
    Posts
    442

    Utility power disconnect

    Hi
    I am wondering that,
    Why utility the local company (LADWP) cut the power at their power pole on this tenant????

    (supplying an existing warehouse doing welding with an existing 3 phase 1200A service, single meter)

    LADWP says "over loading"

    How do they knew it was over load ????

    note that, supplying conductors have 230A apoxim. sized base on previous tenant's demand load.

    Thank you

  2. #2
    Join Date
    Mar 2013
    Location
    Rutland, VT, USA
    Posts
    349
    There could be several reasons. Utility companies size the transformers based on the loads of the customer. For new customers, there is usually a load sheet that needs to be filled out when applying for service (commercial/industrial customers) and the transformer(s) sized to that. What can happen over time is that customers start adding load without notifying the utility. Typically the customers demand kw is known and if that increases to the point where it is more than the transformers capacity, the utility would notify the customer and start discussion on increasing the transformer size. There may also be a rate tariff issue here.

    If the load has dramatically increased it may have adverse affects on the distribution system supplying the customer so the utility may have shut the power off to that customer to protect the system and other customers.

  3. #3
    Join Date
    Nov 2015
    Location
    CA, USA
    Posts
    681
    The rating of service entrance equipment is not a guarantee that the utility is supplying a service with that rating. I've seen plenty of deviation in this area. The utility usually sizes the service based on what they plan your load to be, so if they think you need 200A and you put in a 1,000A SE panel you still get a 200A service. That might be the issue here. If there is an increase in load from a previous usage of the building then the utility needs to be contacted for a possible service upgrade.

    How do they know? They monitor power flow on the distribution system. If they noticed an increase on a line section then they look on that line to identify the specific customer.

  4. #4
    Join Date
    Feb 2016
    Location
    Illinois
    Posts
    1,094
    Quote Originally Posted by pv_n00b View Post

    How do they know?

    .
    Smart meters

  5. #5
    Join Date
    May 2018
    Location
    Jamaica and london
    Posts
    936
    Because of theft Utilities monitor at a lot more places so the idea of smart meters is pretty much part of it. They also have switching setups to find where they need loads, and all that is monitored in case they need to upgrade equipment or shift equipment... if they see something causing them problems they investigate further...
    Student of electrical codes. Please Take others advice first.

  6. #6
    Join Date
    Feb 2007
    Location
    USA
    Posts
    5,780
    They cut power without notification?

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