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Thread: Nameplate Rating Bussing

  1. #11
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    Quote Originally Posted by ggunn View Post
    I have never drilled a hole in a bus to land PV connection terminals. I have found open holes just like the ones the service conductor terminals are landed on and gotten the OK from the switchgear manufacturer to use them for PV interconnection.
    I've talked to many switchboard manufacturers and have never found one that will approve landing at an unused hole that is not marked for taps. What manufacturers have you worked with who have approved it? Did they send you an approval letter or was it over the phone? I'd like to know who to work with.

  2. #12
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    I've always thought that when 705.12(B)(2)(3) on busbar rating referred only to panelboards that it was just a typo since (B) says the provisions apply to all distribution equipment. But I've been asking around and someone on CMP4 told me that it was intended to only apply to panelboards because they have more restriction on loading than switchgear. I was also told that in 2020 this will be made more clear by stating that interconnections to switchboards and switchgear will require engineering supervision just as 705.12(B)(2)(3)(e) requires for multi-ampacity busbars. That's great on one hand since it removes all the busbar rule of thumb restrictions in (B)(2)(3), but requires an engineer to decide how much can be back fed.

  3. #13
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    Quote Originally Posted by pv_n00b View Post
    I've talked to many switchboard manufacturers and have never found one that will approve landing at an unused hole that is not marked for taps. What manufacturers have you worked with who have approved it? Did they send you an approval letter or was it over the phone? I'd like to know who to work with.
    One was, I believe, GE, who sent over a rep and gave me a letter. The other I don't remember who it was. They were unresponsive for a long time, but finally one of their engineers told me over the phone "Of course you can; the holes are there for parallel sets, and if they aren't all filled you can use the open ones for PV." He kind of acted like I was asking a dumb question. The AHJ wanted it in writing; they accepted an email from the engineer.

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