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Thread: Does Tesla powerwall have to comply with NEC 2014 702.4.(B)(2)?

  1. #1
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    Does Tesla powerwall have to comply with NEC 2014 702.4.(B)(2)?

    Hello,
    Section 702 is not just about prime movers. Reading 702.2 definition, this section applies to Energy Storage Systems. Does Tesla powerwall have to comply with NEC 2014 702.4.(B)(2)? Can it connect to the main panel and feeds bunch of loads of the main panel? I don't see load management/load shedding strategy here given that fact that a powerwall can only output 7kW at 240V. Tesla says they have an mobile app to turn on/off specific loads but how is it possible if the contractor connects the single powewall directly to the main panel?

    Thanks.
    Last edited by fandi; 06-13-18 at 10:56 AM.

  2. #2
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    Quote Originally Posted by fandi View Post
    Hello,
    Section 702 is not just about prime movers. Reading 702.2 definition, this section applies to Energy Storage Systems. Does Tesla powerwall have to comply with NEC 2014 702.4.(B)(2)? Can it connect to the main panel and feeds bunch of loads of the main panel? I don't see load management/load shedding strategy here given that fact that a powerwall can only output 7kW at 240V. Tesla says they have an mobile app to turn on/off specific loads but how is it possible if the contractor connects the single powewall directly to the main panel?

    Thanks.
    702.4 Capacity and Rating.
    (A) Available Short-Circuit Current. Optional standby system
    equipment shall be suitable for the maximum available shortcircuit
    current at its terminals.
    (B) System Capacity. The calculations of load on the standby
    source shall be made in accordance with Article 220 or by
    another approved method.
    (1) Manual Transfer Equipment. Where manual transfer
    equipment is used, an optional standby system shall have
    adequate capacity and rating for the supply of all equipment
    intended to be operated at one time. The user of the optional
    standby system shall be permitted to select the load connected
    to the system.
    it seems to me the app idea would be compliant with 702.4 (B)(1) so 702.4 (B)(2) would not apply. Also the user could select what loads to use by turning on/off circuit breakers.
    Bob

  3. #3
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    Quote Originally Posted by petersonra View Post
    it seems to me the app idea would be compliant with 702.4 (B)(1) so 702.4 (B)(2) would not apply. Also the user could select what loads to use by turning on/off circuit breakers.
    Thanks, Bob.

  4. #4
    Join Date
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    The Powerwall system does not use a manual transfer method. I don't think one can invoke that section.
    Last edited by jaggedben; 06-13-18 at 07:26 PM.

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