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Thread: Load- or line side tie?

  1. #11
    Join Date
    Jan 2012
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    CA
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    Thanks Golddigger,
    Yes, the issue is that the 200 and 30 can add, thus exceeding the 200A (E) feeder wire's ampacity.
    Re. upgrading the feeder wire...it's 4/0 SE cable (the heavy romex type stuff) inside walls, up several stories.....no way!

    Thanks Smartmoney,
    Yes, replacing the short and tightly bent conductors from meter to line side of main breaker would physically work (to allow tap) ...........it gets into violating the listing of the combination meter/main, etc. Stuff I do not know much about - but the inspector does....
    Yeah, you are right pulling the meter is no problem - and exactly what i would do in order to tap line-side.

    Thanks JaggedBen,
    Yeah, replacing conductors as above may be an option in the future. I do seriously doubt any mfctr would say yes, though. Why would they, they could only stand to lose.
    On the other hand: Let's put it this way, if there were no AHJ, i would do it in a heartbeat: i know my work and would use the right wire. Come to think of it, w/o the photo above....who would know there hadn't always been nice big, pig-tailed loops on the SE conductors...???
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    I've learned a lot for future reference, that 'll be mighty handy!

    Right now i think i got it:
    I heard of a 200 AMP branch circuit breaker that i can add to a 200 amp panel!
    Turns out, Square D makes it in both HOM and QO. Takes 4 spaces (instead of 2).
    This'll plug onto any HOM or QO busbar. So i'll take the (E) 4/0 sub-panel feeder conductors from the (E) 200A main breaker and feed them off of this. Place this (N) 200A breaker in a new subpanel (in the middle of the busbar somehwere) and plug my (N) 2p30A PV Breaker on the bottom.
    That should meet 120% rule and "opposite feed" section of said rule.
    The things solar will make you do.........
    Last edited by Zee; 11-05-13 at 09:49 PM.

  2. #12
    Join Date
    Oct 2006
    Posts
    3,254
    Quote Originally Posted by Zee View Post
    Thanks Golddigger,
    Yes, the issue is that the 200 and 30 can add, thus exceeding the 200A (E) feeder wire's ampacity.
    Re. upgrading the feeder wire...it's 4/0 SE cable (the heavy romex type stuff) inside walls, up several stories.....no way!

    Thanks Smartmoney,
    Yes, replacing the short and tightly bent conductors from meter to line side of main breaker would physically work (to allow tap) ...........it gets into violating the listing of the combination meter/main, etc. Stuff I do not know much about - but the inspector does....
    Yeah, you are right pulling the meter is no problem - and exactly what i would do in order to tap line-side.

    Thanks JaggedBen,
    Yeah, replacing conductors as above may be an option in the future. I do seriously doubt any mfctr would say yes, though. Why would they, they could only stand to lose.
    On the other hand: Let's put it this way, if there were no AHJ, i would do it in a heartbeat: i know my work and would use the right wire. Come to think of it, w/o the photo above....who would know there hadn't always been nice big, pig-tailed loops on the SE conductors...???
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    I've learned a lot for future reference, that 'll be mighty handy!

    Right now i think i got it:
    I heard of a 200 AMP branch circuit breaker that i can add to a 200 amp panel!
    Turns out, Square D makes it in both HOM and QO. Takes 4 spaces (instead of 2).
    This'll plug onto any HOM or QO busbar. So i'll take the (E) 4/0 sub-panel feeder conductors from the (E) 200A main breaker and feed them off of this. Place this (N) 200A breaker in a new subpanel (in the middle of the busbar somehwere) and plug my (N) 2p30A PV Breaker on the bottom.
    That should meet 120% rule and "opposite feed" section of said rule.
    The things solar will make you do.........
    You could do a load calc and down size the main OCPD.

  3. #13
    Join Date
    Jun 2006
    Location
    Ohio
    Posts
    13,319
    Quote Originally Posted by Zee View Post
    ...

    Thanks Smartmoney,
    Yes, replacing the short and tightly bent conductors from meter to line side of main breaker would physically work (to allow tap) ...........it gets into violating the listing of the combination meter/main, etc. Stuff I do not know much about - but the inspector does....

    ...
    Have you looked into double/dual lugs at the meter end of the conductors, or tapping the conductors on the meter side of the combo (such as with insulation-piercing tap connectors; not a fan, but if all else fails...)?

    Ultimately, have you actually asked the AHJ if there is a method to tap the service conductors that'll meet their approval?
    I'll never get there. No matter where I go, I'm always here.

  4. #14
    Join Date
    Jan 2012
    Location
    CA
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    278
    Quote Originally Posted by Smart $ View Post
    Have you looked into double/dual lugs at the meter end of the conductors, or tapping the conductors on the meter side of the combo (such as with insulation-piercing tap connectors; not a fan, but if all else fails...)?

    Ultimately, have you actually asked the AHJ if there is a method to tap the service conductors that'll meet their approval?
    Thanks,
    Nope, i assumed they would not allow me to do anything in the meter enclosure.
    I should ask them. Next time. The new sub-panel will work now.

  5. #15
    Join Date
    Jan 2012
    Location
    CA
    Posts
    278
    I'll be feeding 200Amps into this new 200A rated sub-panel.

    I'll be feeding it with 2 @ 3/0 hot wires from the main panel and a #6 EGC from the main panel - thru a 2" offset nipple.

    Can i run a single 3/0 NEUTRAL conductor from the (E) main panel's neutral bar to the neutral in the new sub-panel?
    (instead of running in and out with the neutral)

  6. #16
    Join Date
    May 2011
    Posts
    1,267
    Just to be clear, the hots are returning to the existing subfeed via the same nipple, right? So you're proposing that the wires through the nipple would be four hots (two in each direction) and one neutral, right?

    The code section at issue is 300.20.

    If not for the solar, I'd say 300.20 is satisfied if you do it as described above, because any hot currents flowing to the existing sub cancel out through the nipple, and you don't have a problem.

    However, since you're going to be adding the solar to the sub, that throws me for a bit of a loop. It's that whole thing of where the unbalanced current comes from and goes to with a utility interactive inverter. Until I see or draw out a diagram I can't say for certain that all the currents in the nipple would cancel out.

    And just to complicated it (maybe) ... ... should we assume it would be possible to have an additional load in the sub as well?

  7. #17
    Join Date
    Oct 2009
    Location
    Austin, TX, USA
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    3,453
    Quote Originally Posted by Zee View Post
    I'll be feeding 200Amps into this new 200A rated sub-panel.
    You know that the 200A in the subpanel counts toward the 120% rule in the main panel, don't you? The main needs to be 1000A if its OCPD and busbar ratings are the same.

  8. #18
    Join Date
    May 2011
    Posts
    1,267
    Quote Originally Posted by ggunn View Post
    You know that the 200A in the subpanel counts toward the 120% rule in the main panel, don't you? The main needs to be 1000A if its OCPD and busbar ratings are the same.
    I think you read too fast. The 200A is the utility feed. The inverter output is 22A.

  9. #19
    Join Date
    Jan 2012
    Location
    CA
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    278
    Thanks Jben,
    Quote Originally Posted by jaggedben View Post
    Just to be clear, the hots are returning to the existing subfeed via the same nipple, right? So you're proposing that the wires through the nipple would be four hots (two in each direction) and one neutral, right?
    Yes. (and a #6 egc of course)
    The code section at issue is 300.20.
    Oh, OK.
    If not for the solar, I'd say 300.20 is satisfied if you do it as described above, because any hot currents flowing to the existing sub cancel out through the nipple, and you don't have a problem.

    However, since you're going to be adding the solar to the sub, that throws me for a bit of a loop. It's that whole thing of where the unbalanced current comes from and goes to with a utility interactive inverter. Until I see or draw out a diagram I can't say for certain that all the currents in the nipple would cancel out.
    EXACTLY what i cannot get my head around.
    And just to complicated it (maybe) ... ... should we assume it would be possible to have an additional load in the sub as well?
    DEFINITELY. Good Q. This will be a big, 30 space panel. WIth a 200 A load breaker and a 30 A "load" aka PV breaker (22A @ 125%) - for starters.

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