Results 1 to 10 of 10

Thread: Is Bottom Feeding Transformers Still Okay?

  1. #1
    Join Date
    Nov 2011
    Location
    California
    Posts
    39

    Is Bottom Feeding Transformers Still Okay?

    I overheard someone saying that transformers can't be bottom fed anymore. Something about rodent access. The most recent transformer submittal that I have seen shows a window that can be used to bottom feed. Is there a new code preventing this? Would this be a manufacturer requirement or code requirement?

  2. #2
    Join Date
    Aug 2004
    Location
    Northern illinois
    Posts
    16,506
    Quote Originally Posted by krist003 View Post
    I overheard someone saying that transformers can't be bottom fed anymore. Something about rodent access. The most recent transformer submittal that I have seen shows a window that can be used to bottom feed. Is there a new code preventing this? Would this be a manufacturer requirement or code requirement?
    I have seen some transformers that came with instructions showing where you should bring in the conduits. I have no idea why. I have only seen it a few times (maybe only once). I don't know if it is mandatory or just a suggestion. It was conveneint for us to follow the guidelines in the instructions so that is what we did without really thinking much more about it.
    Bob

  3. #3
    Join Date
    Jun 2004
    Location
    Cherry Valley NY, Seattle, WA
    Posts
    4,219
    Quote Originally Posted by krist003 View Post
    I overheard someone saying that transformers can't be bottom fed anymore. Something about rodent access. The most recent transformer submittal that I have seen shows a window that can be used to bottom feed. Is there a new code preventing this? Would this be a manufacturer requirement or code requirement?
    Hogwash
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

  4. #4
    Join Date
    Aug 2004
    Location
    Northern illinois
    Posts
    16,506
    https://hubbellcdn.com/technicaldraw...L_DRAWINGS.pdf

    This drawing shows that conduit should come in the side or along the edges of the bottom on this unit. I think the bottom is screened for ventilation.
    Bob

  5. #5
    Join Date
    Nov 2011
    Location
    California
    Posts
    39
    I would understand if this was a manufacturing thing and perhaps certain special transformers do not have a provision for bottom feed for whatever reason, but I was a little taken back when someone suggested that you can no longer bottom feed transformers at all. I doubt that is the case, but when I hear things like this I like to get the full scoop.

  6. #6
    Join Date
    Aug 2004
    Location
    Northern illinois
    Posts
    16,506
    Quote Originally Posted by krist003 View Post
    I would understand if this was a manufacturing thing and perhaps certain special transformers do not have a provision for bottom feed for whatever reason, but I was a little taken back when someone suggested that you can no longer bottom feed transformers at all. I doubt that is the case, but when I hear things like this I like to get the full scoop.
    you should ask whomever it was you heard it from why he thinks this.
    Bob

  7. #7
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    36,198
    If rodent access is the issue - typical dry type transformers usually don't have an open bottom, some have ventilation openings in the bottom, but small enough they are not a rodent access issue. Your conductors will enter via raceway/cable fittings - still not a rodent issue if done properly.

    Pad mount type transformers typically have open bottom design and conductors don't enter via a "bottom wall" But rodent access is an issue with those even if you don't bring conductors into the bottom - cause it is open anyway.

    Ask a rural POCO guy about opening a padmount and finding not only rodents but other animals like skunks, raccoons, snakes, etc. getting into such transformer wiring cabinets from time to time when a burrowing critter happens to burrow into the space under the transformer. Skunks won't burrow but will invade an existing burrow dug by some other critter.
    I live for today, I'm just a day behind.

  8. #8
    Join Date
    Nov 2011
    Location
    California
    Posts
    39
    I agree with your reasoning. I wish I would have asked where he got this info from, but didn't think much of it at the time. Glad to hear I am not missing out on some commonly known issue.

  9. #9
    Join Date
    Mar 2016
    Location
    The Motor City, Michigan USA
    Posts
    691
    Quote Originally Posted by kwired View Post
    ... rodents ... skunks, raccoons, snakes, ...
    So a pad-mount base should include a rat wall?

  10. #10
    Join Date
    Oct 2009
    Location
    Austin, TX, USA
    Posts
    9,288
    Quote Originally Posted by drcampbell View Post
    So a pad-mount base should include a rat wall?
    Remember Crispy Critters?

Posting Permissions

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