User Tag List

Page 1 of 2 1 2 LastLast
Results 1 to 10 of 15

Thread: Connecting PV to an existing MLO service panel

  1. #1
    Join Date
    Oct 2014
    Location
    Los Angeles
    Posts
    162
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Connecting PV to an existing MLO service panel

    Hello All,
    (Under NEC 2014) Would a PV connection (via a PV breaker) to an existing MLO panel considered a supply side connection? (To me it's a load side connection because the PV breaker takes one of the MLO panel's feeder breaker slots)
    And if it's not a supply side connection, would this following configuration comply with 705.12(D)(2)(3)(a)?
    48A output inverter connects to a 100A MLO panel via a 60A PV breaker.
    125% x 48A + 0A <=100A.
    Assumptions:
    - Manufacturer cutsheet of that MLO panel allows PV system to connect to the panel via a PV breaker.
    - the total breakers (PV breaker plus all existing feeder breakers) are no greater than 6.

    Also, if it's a load side connection, is there any of the 705.12 section requires the service panel has to have a main breaker in order for the PV system to hook up? I see that NEC 2014 705.22 only requires a disconnect device at the main service panel, not a OCPD. Meaning an external disconnect ahead of the MLO panel would suffice.
    Thanks.
    Last edited by fandi; 01-08-19 at 05:43 PM.

  2. #2
    Join Date
    Jun 2004
    Location
    Cherry Valley NY, Seattle, WA
    Posts
    5,493
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Yes it is a supply side connection. It is a bit odd that the 120% rule doesnt apply in that situation. I wonder if that was an oversight by the code makers.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  3. #3
    Join Date
    Oct 2014
    Location
    Los Angeles
    Posts
    162
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by electrofelon View Post
    Yes it is a supply side connection. It is a bit odd that the 120% rule doesnt apply in that situation. I wonder if that was an oversight by the code makers.
    Can you explain why is that a supply side connection? Thx.

  4. #4
    Join Date
    Oct 2014
    Location
    Los Angeles
    Posts
    162
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I think anything ahead of the meter is considered supply side. And anything after the meter is considered load side.

  5. #5
    Join Date
    Jun 2004
    Location
    Cherry Valley NY, Seattle, WA
    Posts
    5,493
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by fandi View Post
    Can you explain why is that a supply side connection? Thx.
    Read 705.12(A), 230.82(6), and the article 100 definition of "service conductors".
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  6. #6
    Join Date
    Oct 2014
    Location
    Los Angeles
    Posts
    162
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by electrofelon View Post
    Read 705.12(A), 230.82(6), and the article 100 definition of "service conductors".
    So per this attached diagram, the only difference between supply side vs load side configurations is the presence of the main breaker? (because other than that, they're the same)
    Name:  Supply side vs Load side configurations.jpg
Views: 112
Size:  6.7 KB

  7. #7
    Join Date
    May 2011
    Posts
    5,151
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Simply, if there is no other disconnecting means between the service point and the PV disconnecting means, then it is not connected on the load side of a service disconnecting means. If it is not load side then it is supply-side.

    Meters have nothing to do with it as far as the NEC is concerned.

  8. #8
    Join Date
    Oct 2014
    Location
    Los Angeles
    Posts
    162
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by jaggedben View Post
    Simply, if there is no other disconnecting means between the service point and the PV disconnecting means, then it is not connected on the load side of a service disconnecting means. If it is not load side then it is supply-side.

    Meters have nothing to do with it as far as the NEC is concerned.
    I agree that meters have nothing to do in this case, but I try to find in the Art 100 about the definitions of 'supply side connection' and 'load side connection' and I can't find them. As you can see in my diagram, the PV connection point is still the same spot. So how do we know when will be supply side connection, and when will be load side connection? And just like your interpretation, the Code needs to make it clear in Art 100 that a connection of the load side of the main breaker is considered load side connection.
    Last edited by fandi; 01-08-19 at 07:58 PM.

  9. #9
    Join Date
    Jun 2004
    Location
    Cherry Valley NY, Seattle, WA
    Posts
    5,493
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by fandi View Post
    I agree that meters have nothing to do in this case, but I try to find in the Art 100 about the definitions of 'supply side connection' and 'load side connection' and I can't find them. As you can see in my diagram, the PV connection point is still the same spot. So how do we know when will be supply side connection, and when will be load side connection?
    I think Jaggadben explained it very clearly. Perhaps its a "small" difference having a main breaker in there, but that is the service disconnect and the Pv is on the load side of the service disconnect.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  10. #10
    Join Date
    Jun 2004
    Location
    Cherry Valley NY, Seattle, WA
    Posts
    5,493
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by fandi View Post
    I agree that meters have nothing to do in this case, but I try to find in the Art 100 about the definitions of 'supply side connection' and 'load side connection' and I can't find them. As you can see in my diagram, the PV connection point is still the same spot. So how do we know when will be supply side connection, and when will be load side connection? And just like your interpretation, the Code needs to make it clear in Art 100 that a connection of the load side of the main breaker is considered load side connection.
    see 705.12(A) and (D). I admit it is not very logically laid out.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •